Proposal Cover SheetNASA Research Announcement 99-OES-04

Proposal No. _____________________ (Leave Blank for NASA Use)LoI Reference No. 357

Satellite-Sunphotometer Studies of Aerosol, Water Vapor and Ozone Rolesin Climate-Chemistry-Biosphere Interactions

Principal Investigator:

Philip B. Russell DateAtmospheric Chemistry and Dynamics Branch

NASA Ames Research Center, MS 245-5Moffett Field, CA 94035-1000

prussell@mail.arc.nasa.gov, Phone: 650-604-5404. Fax: 650-604-6779

Co-Investigators:Beat Schmid, Bay Area Environmental Research Institute (Tel. 650-604-5933, bschmid@mail.arc.nasa.gov)

Jens Redemann, Bay Area Environmental Research Institute (Tel. 650-604-6259,jredemann@mail.arc.nasa.gov)

John M. Livingston, SRI International (Tel. 650-604-3386, jlivingston@mail.arc.nasa.gov)Robert W. Bergstrom, Bay Area Environmental Research Institute (Tel. 650-604-6261,

bergstro@sky.arc.nasa.gov)Kenneth J. Voss, University of Miami (Tel. 305-284-2323, voss@physics.miami.edu)

Didier Tanre, Universite des Sciences et Technologies de Lille (Tel. 33 (0)3 20 33 70 33,

Didier.Tanre@univ-lille1.fr)Jay R. Herman, NASA Goddard Space Flight Center (Tel. 301-614-6039, herman@tparty.gsfc.nasa.gov)

Budget:1st Year: $225K 2nd Year $267K 3rd Year: $309K 4th Year: Total: $800K

(OVWST Only)Program Element (select one or more)

____ Global Modeling and Analysis Program (GMAP)_X_ Atmospheric Chemistry Modeling and Analysis Program (ACMAP)____ Physical Oceanography Research and Analysis Program (PORAP)____ Ocean Vector Winds Science Team (OVWST)____ Pathfinder Data Set and Associated Science Program (PDSP)_X_ EOS Interdisciplinary Science Program (EOS/IDS)

Reviewed by: R. Stephen Hipskind Date

Authorizing Official: Estelle P. Condon, Chief DateEarth Science DivisionNASA Ames Research Center

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TABLE OF CONTENTS

Page

LIST OF TABLES AND ILLUSTRATIONS i

LIST OF ACRONYMS ii

ABSTRACT iii

PROGRAM RELEVANCE iii

1 OBJECTIVES, EXPECTED SIGNIFICANCE, AND GENERAL APPROACH 1

2 BACKGROUND: FIELD CAMPAIGNS AND EXPECTED ROLES OF SATELLITE AND

AIRBORNE SUNPHOTOMETER DATA PRODUCTS 2

2.1 SAFARI 2000 2

2.2 African Dust Plume and Water-Leaving Radiance Opportunities on SAFARI 2000 Transits 7

2.3 ACE Asia Survey and Evolution Component 7

2.4 Other Possible Experiments 10

3 PROPOSED RESEARCH 10

3.1 Year One: Tasks 1.1 Ð 1.6 10

3.2 Years Two and Three: Tasks 2.1 Ð 2.6 13

4 SCHEDULE 16

5 REFERENCES 16

6 BUDGET 22

7 STAFFING, RESPONSIBILITIES, AND VITAE 25

8 CURRENT SUPPORT 35

TABLE

1. Satellites, sensors, data products, and planned field campaigns relevant to this proposal 38

ILLUSTRATIONS

1. Latitude transects of aerosol optical depth and �ngstr�m exponent derived from the AATS-6sunphotometer aboard the UW C-131A, from ATSR-2, and from AVHRR.

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2. Aerosol optical thickness measured by sunphotometer (AATS-6) aboard the C-131A aircraftand derived from MAS data as a function of wavelength.

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3. Aerosol optical depths measured in ACE 2 by AATS-6 on the R/V Vodyanitskiy, AATS-14on the Pelican aircraft, and AVHRR on the NOAA-14 Satellite.

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4. Profiles of aerosol optical depth and extinction at selected AATS-14 wavelengths (380, 500,864 and 1558 nm) measured in ACE 2.

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5. Comparison of aerosol optical depth spectra for the marine boundary layer during a Pelicanflight in ACE 2.

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6. Marine boundary layer aerosol size distributions from in situ measurements and inverted fromAATS-14 extinction spectra measured on Pelican flight tf15 in ACE 2.

F6

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ILLUSTRATIONS (ContÕd) Page7. Profiles of the columnar water vapor and water vapor density measured in ACE 2 by AATS-

14 and in situ sensor.F7

8. Scatter diagram of columnar water vapor calculated from radiosonde measurements and fromAATS-6 measurements during ACE 2.

F8

9. Aerosol single-scattering albedo profiles determined for TARFOX flight 1728 (July 17, 1996)by two techniques.

F9

10. Comparison between aerosol-induced change in solar flux derived from C-130 pyranometermeasurements (data points) and calculations (curves).

F10

11. Aerosol-induced change in net shortwave flux at tropopause calculated from satellite maps ofaerosol optical depth and aerosol intensive properties from TARFOX.

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12. Channel wavelengths of Ames Airborne Tracking Sunphotometers (AATS-6 and AATS-14)in relation to atmospheric spectra.

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ACRONYMS

AA-SEC ACE Asia Survey and Evolution ComponentAATS-6 6-channel Ames Airborne Tracking SunphotometerAATS-14 14-channel Ames Airborne Tracking SunphotometerACE Aerosol Characterization ExperimentADEOS Advanced Earth Observing SatelliteASTER Advanced Spaceborne Thermal Emission and Reflection RadiometerATSR Along-Track Scanning RadiometerAVHRR Advanced Very High Resolution RadiometerBOREAS Boreal Ecosystem-Atmosphere StudyCERES Clouds and the EarthÕs Radiant Energy SystemEOS Earth Observing SystemFIFE First ISLSCP Field ExperimentGOES Geostationary Operational Environmental SatelliteHAPEX-Sahel Hydrologic-Atmospheric Pilot Experiment in the SahelISLSCP International Satellite Land Surface Climatology ProjectLITE Lidar In-space Technology ExperimentOES Office of Earth ScienceMAS MODIS Airborne SimulatorMISR Multi-angle Imaging Spectro-RadiometerMODIS Moderate-resolution Imaging SpectroradiometerMOPITT Measurements of Pollution in the TropospherePICASSO-CENA Pathfinder Instruments for Cloud and Aerosol Spaceborne Observations –

Climatologie Etendue des Nuages et des AerosolsPOLDER Polarization and Directionality of the EarthÕs ReflectancesSAFARI Southern African Fire-Atmosphere Regional Science InitiativeSAGE Stratospheric Aerosol and Gas ExperimentSCAR-B Smoke, Clouds And Radiation experiment in BrazilSeaWiFS Sea-viewing Wide-Field-of-view SensorSEC Survey and Evolution Component [of ACE Asia]SSFR Spectral Solar Flux RadiometerTARFOX Tropospheric Aerosol Radiative Forcing Observational ExperimentTOMS Total Ozone Mapping SpectrometerTRACE-A Transport and Chemistry Near the Equator-AtlanticTRACE-P Transport and Chemical Evolution over the Pacific

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Satellite-Sunphotometer Studies of Aerosol, Water Vapor and Ozone Rolesin Climate-Chemistry-Biosphere Interactions

ABSTRACT: We propose modeling and integrated analyses of suborbital and satellite data toaddress impacts of biomass smokes, Asian and African soil dust, and other tropospheric aerosols,water vapor, and ozone on the EarthÕs radiation budget and on remote measurements of ocean colorand terrestrial ecology. Research will focus on analysis of data from international multiplatformfield campaigns such as SAFARI 2000 and ACE Asia. Data from airborne sunphotometers and otherairborne and surface remote and in situ measurements will be combined in closure studies that testand improve models of complex multicomponent tropospheric aerosols and their interactions withwater vapor and radiation. Pre-campaign modeling and algorithm development will focus onproviding realtime analysis and display capabilities useful for studies of aerosol evolution and massbudgets, including flight planning and direction. During and after campaigns suborbital data andmodels will be used to validate satellite measurements of aerosols, water vapor, and ozone, plusatmospheric corrections of satellite ocean color and terrestrial measurements. They will then beused to supplement the satellite data with other information needed for studies of aerosolphysicochemical evolution and radiative-climatic effects. In particular, satellite maps of aerosolproperties will be combined with suborbital data in radiative transfer models to assess aerosol effectson radiation balance and heating rates, both at the surface and aloft.

PROGRAM RELEVANCE: This proposal is aimed primarily at the EOS Interdisciplinary ScienceProgram (EOS/IDS) and secondarily at the Atmospheric Chemistry Modeling and Analysis Program(ACMAP). It addresses three of the five priority research themes of NASAÕs Earth ScienceEnterprise cited in the NRA. Specifically, within the Climate Variability and Change theme, itaddresses understanding, modeling, and predicting climate change caused by three radiatively activeconstituents: aerosols, water vapor, and ozone; within the Atmospheric Chemistry theme it addressestropospheric pollution and its transport and transformations over regional-to-global scales; andwithin the Ecosystems and Global Carbon Cycle theme it addresses the remote measurement ofterrestrial and marine ecosystems via the removal of atmospheric effects from those measurements.The proposal also addresses several of the cross-disciplinary subjects listed in the EOS/IDS sectionof the NRA (Appendix A, Section 2.f): Atmospheric chemistry and climate (specifically,tropospheric aerosol effects on radiative balance), Land-climate feedback (specifically, the impact ofbiomass fires on biogeochemical cycling and remote measurements of ecosystem processes), andCoastal region processes (specifically, the impact of biomass burning and airborne soil dust oncoastal waters and their remote measurement). It will use data from such multi-national, multi-agency field campaigns as SAFARI-2000 and the Aerosol Characterization Experiment (ACE)Asian mission cited in the ACMAP section of the NRA (Appendix A, Section 2.b). The proposedresearch will combine airborne and surface-based measurements from those campaigns to validateand complement atmospheric, oceanic, and terrestrial data products from such satellites and sensorsas EOS Terra, TOMS, ADEOS II/POLDER, and SeaWiFS. The combined satellite and suborbitaldata will be used to drive models of aerosol and water vapor effects on radiation budgets and remotemeasurements and also to test and advance models of aerosol optical properties and their relation toaerosol chemical and physical processes.

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1 OBJECTIVES, EXPECTED SIGNIFICANCE, AND GENERAL APPROACH

The overall objective of the proposed research is to improve understanding of interactions between chemistry,climate and the biosphere, and to advance remote measurement science, by combining data from space,aircraft and the surface in innovative ways. Questions to be addressed include the impact of complextropospheric aerosols on radiative balance, the effects of water in vapor and condensed phases on radiationand aerosol properties, the role of biomass burning in land-climate interactions, and the effects of atmosphericproperties on remote measurements of ocean color, terrestrial ecosystems, and associated biogeochemicalprocesses. The research will stress analysis of data from multiagency field campaigns (e.g., SAFARI-2000,ACE Asia) that combine airborne sunphotometry of aerosols, water vapor and ozone with in situ, satellite,and other remote measurements.

Satellite measurement science is advancing rapidly (e.g., Kaufman et al., 1997; Gordon et al., 1997; King etal., 1999). Recently TOMS measurements, designed to monitor ozone, were shown to contain valuableinformation on aerosol geographical distributions (Herman et al., 1997) which have been used to find anincrease in biomass burning smoke in the African savanna regions during the 1990s (Hsu et al., 1999).SeaWiFS, developed to provide ocean color data products for the study of marine biogeochemical processes,produces an aerosol data product from its atmospheric correction algorithm, and it has been used to documenttransport of Asian dust plumes across the Pacific Ocean (Kuring et al., 1999). With the upcoming launch ofEOS Terra, new instruments like MODIS and MISR will provide improved measurement capabilities andunprecedented volumes of data on the atmosphere, land, ocean, and radiative processes (e.g., Tanre et al.,1997; Wanner et al., 1997). The launch of POLDER on ADEOS II will add more capabilities (e.g., Leroy etal., 1997). Extracting the full potential from these satellite data requires correlative suborbital data, not only tovalidate the satellite measurements (e.g., Clark et al., 1997; Fraser et al., 1997; Vermote et al., 1997), but tosupply information not obtainable from space.

Airborne sunphotometry, a desired component of planned multinational field campaigns, has the potential toplay a strong role in providing both these types of correlative data. The strength of airborne sunphotometry isits unique ability to measure four-dimensional fields of aerosol optical depth and extinction spectra (near UV- visible - near IR) and water vapor and ozone columns, all at times and locations chosen by the experimenter,including coincidences with satellite overpasses. Data from airborne sunphotometer transects over the ocean,the ocean-land interface, and other surfaces of varying reflectivities, as well as from transects across gradientsof aerosol, water vapor, and ozone columns, can be used to test satellite retrievals of aerosols, ocean color,and land surface properties under a wide range of conditions and degrees of difficulty. Furthermore, datafrom airborne sunphotometer vertical profiles show the relative altitudes of aerosol, water vapor, Rayleigh,and ozone extinction. When combined with simultaneous airborne measurements of radiative fluxes, suchsunphotometer vertical profile measurements can provide information on absorption by the ambient aerosol(undistorted by sampling processes), which can be compared to in situ measurements of aerosol scatteringand absorption, to judge their mutual consistency and assess potential artifacts of each measurementprocesses. Such vertical profile studies are important not only to aerosol effects on radiation budgets andclimate, but to atmospheric corrections of ocean color measurements (e.g., Clark et al., 1997), which areparticularly sensitive to aerosol vertical distribution when the aerosols are absorbing (e.g., in plumes ofsmoke, industrial haze, and/or soil dustÑsee, e.g., Nakajima and Higurashi, 1997; Nakajima et al., 1989).

This proposal requests funding for studies that will exploit the full potential of airborne sunphotometry bypermitting the interdisciplinary, multi-instrument analyses that typically do not fit within themission/measurement funding for such multinational campaigns. The potential is exemplified by thecontributions to a variety of disciplines made by previous measurements and analyses using the AmesAirborne Tracking Sunphotometers (AATS-6 and AATS-14). These contributions include:

¥ Atmospheric corrections in remote sensing of terrestrial ecosystems and biogeochemical processes duringstudies such as the International Satellite Land Surface Climatology Program (ISLSCP), the Hydrologic-Atmospheric Pilot Experiment in the Sahel (HAPEX-Sahel), and the Boreal Ecosystem-Atmosphere Study(BOREAS) (Spanner et al., 1990; Wrigley et al., 1992),

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¥ Validation of aerosol data products from SAGE II, AVHRR, GOES Imager, ATSR-2, and MODISAirborne Simulator (Russell et al., 1986; Livingston and Russell, 1989; Veefkind et al., 1999; Durkee et al.,1999; Tanre et al., 1999),

¥ Studies of oil- and forest-fire smokes and cirrus clouds (Pueschel et al., 1988; Pueschel and Livingston,1990),

¥ Studies of radiative and chemical effects of tropospheric and stratospheric aerosols (Bergstrom andRussell, 1999; Russell et al., 1993a,b; 1996, 1999; Toon et al., 1993),

¥ Apportionment of aerosol optical depth to aerosol chemical constituents (e.g., Hegg et al., 1997; Collins etal., 1999),

¥ Other closure studies to judge the mutual consistency of remote and in situ aerosol measurements and themodels that link them (e.g., Schmid et al., 1999; Livingston et al., 1999; Redemann et al., 1999a; Russelland Heintzenberg, 1999; Welton et al., 1999), and

¥ Intercomparisons of water vapor measurement techniques (e.g., Schmid et al., 1999a,b; Livingston et al.,1999).

The proposed work will include tests of satellite retrieval algorithms and studies of possible improvements byincorporating realistic models of complex aerosols, water vapor and ozone effects that are based on fieldcampaign measurements with both in situ and remote sensors. When appropriate, it will include generation ofnew, illustrative satellite data products using improved algorithms. It will also include regional and globalmodel calculations of radiative effects of realistic aerosols, water vapor, and ozone. These model calculationswill be based on integration of satellite, aircraft, and surface data, analogous to our approach in previousstudies (e.g., deriving North Atlantic regional aerosol radiative effects by combining AVHRR midvisibleoptical depth fields with intensive properties obtained from the sunphotometer and other correlative data;Bergstrom and Russell, 1999). More broadly, they will examine the relationship between atmosphericchemical change and climate change, e.g., by integrating and intercomparing satellite and other results fromsuch experiments as SAFARI-2000 and ACE Asia. These experiments are expected to provide many caseswhere airborne sunphotometer measurements are coordinated with satellite overpasses during biomassburning, continental plume transport over oceans, aerosol physico-chemical evolution, and oceanic processesrevealed by spaceborne color measurements. The proposed research will perform innovative analyses andimprove aerosol optical models to combine the resultant data sets in addressing the above questions.

2 BACKGROUND: PLANNED BIOGEOCHEMICAL FIELD CAMPAIGNS AND EXPECTEDROLES OF SATELLITE AND AIRBORNE SUNPHOTOMETER DATA PRODUCTS

2.1 SAFARI 2000

2.1.1 SAFARI 2000 Goals and Overall Approach. The Southern African Fire-Atmosphere RegionalScience Initiative (SAFARI 2000) is an international, interdisciplinary science initiative designed to increaseour understanding of the southern African ecological and climate system as a whole, as well as its relationshipto hemispheric and global climate (Swap et al., 1998a,b; Swap and Annegarn, 1999). Its goal is to understandthe key linkages between the physical, chemical and biological processes, including human impacts, essentialto the southern African biogeophysical system. Specific objectives of SAFARI 2000 are to:

1. Characterize and quantify the biogenic, pyrogenic and anthropogenic aerosol and trace gas sources andsinks in southern Africa;

2. Validate these observations using atmospheric transport and chemistry models, ground-based, air-borne,and satellite-based observations; and

3. Determine the climatic, hydrological, and ecosystem consequences of these biogeochemical processes.

SAFARI 2000 aims to exploit the unique environmental features of southern Africa, which include a semi-closed atmospheric circulation with clearly defined inflow and outflow regions, favorable to mass balance(Òbudget-closingÓ) experiments. This is especially so in austral winter, when anticyclonic circulation andassociated clear sky conditions favoring satellite and airborne remote sensing dominate the region on as manyas 80% of days. Within this context strong emissions of aerosols and trace gases from heavy industry and

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some of the worldÕs most extensive biomass burning combine to effect significant changes in thebiogeochemical cycling of the region, which includes significant natural biogenic emissions of volatileorganic carbon. Manifestations of these processes include not only strong regional hazes but alsoanomalously large concentrations of ozone in the middle and upper troposphere over the south Atlantic.

SAFARI 2000 addresses a list of scientific questions (Swap et al., 1998a,b; Swap and Annegarn, 1999).Those of greatest interest to this proposal are:

¥ What are the sources, magnitudes, locations and temporal pattern of aerosol and trace gas emissions into theatmosphere over Southern Africa?

¥ What urban, industrial and transport activities within Southern Africa are responsible for aerosol and tracegas emissions?

¥ What ecosystem processes are responsible for aerosol and trace gas emissions?¥ How do climate and other environmental conditions affect these processes?¥ What are the chemical properties of the aerosols emitted?¥ How are aerosols and trace gases chemically transformed and transported between the surface and the

atmosphere and within the southern African atmosphere?¥ How do complex mixtures of gases and aerosols interact in a sunny, dry environment, where they are often

contained within narrow stable layers?¥ How are these atmospheric constituents transported into and out of the region, and what quantity is

transported?¥ How might changes in atmospheric aerosols and trace gas concentrations affect the regional climate,

biogeochemistry and land use of Southern Africa?¥ How do changes in ecosystem functioning and land-surface processes affect emissions and thereby

atmospheric chemistry and radiative forcing of the southern African atmosphere?

To address these questions the SAFARI 2000 Science Plan (Swap and Annegarn, 1999) specifies a suite ofmeasurement and modelling activities, organized into core elements. Of greatest interest to this proposal areCore Elements 3-6 (Aerosols, Trace Gases, Clouds and Radiation, and Modelling). These include ground-based, airborne, and satellite measurements to characterize aerosol concentrations, size-resolved composition(including secondary organic aerosols), optical thickness, and direct and indirect radiative forcing; trace gascomposition, concentration, and optical and radiative properties; and changes in regional radiative transfer.Modeling activities include studies of ozone formation, modeling of aerosol physico-chemical-opticalproperties (including size-resolved composition, optical thickness, and scattering angular dependence), andmodeling of radiative transfer. The Modeling Core Element includes validation of satellite products.

SAFARI 2000 will be conducted over a three-year period, starting in 1999, with three intensive ground andflying field campaigns. This proposal focuses on modeling and data analysis associated with the thirdcampaign, scheduled for August-September 2000, during the dry season. This campaign will track themovement, transformations, and deposition of dry-season emissions from biomass burning and other sources.Ground measurements will include a relatively dense deployment of AERONET sun/skyphotometers (Holbenet al., 1998) plus core field site towers supporting a variety of radiometers to measure surface albedo, amongother properties. Aircraft expected to participate include the NASA ER-2 for remote measurements, theUniversity of Washington CV-580 for in-situ measurements of clouds, aerosols, trace gases, and radiation,and two Aero Commanders operated by African organizations.

2.1.2. Satellite Data Products Relevant to SAFARI 2000 and this Proposal. The EOS Terra platformwill carry the sensors MODIS, MISR, MOPITT, ASTER, and CERES. As shown in Table 1, each of these isexpected to produce data products relevant to SAFARI 2000 and this proposal. For example, MODIS andMISR will produce aerosol optical depth spectra that will be used to study aerosol spatial distributions,transport, evolution, and radiative forcing. MODIS will also produce column water vapor and column ozone.ASTERÕs fine spatial resolution is expected to help pinpoint fires and fine-scale land-cover change and use;however, ASTER will rely on MODIS and MISR aerosol, water vapor, and ozone products for atmosphericcorrections. MOPITT is expected to help resolve large-scale source, sink, and transport questions via itscarbon monoxide and methane measurements; however, possible impacts of strong vertical gradients (i.e.,

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stratified profiles) and dense smoke aerosols on those products need to be investigated. CERES will producedata products describing various radiances, albedos, and fluxes useful in radiative forcing studies. TOMSsensors on several platforms (e.g., Earth Probes, and the new GLI on ADEOS II) will provide regional mapsof both column ozone and aerosol index. POLDER on ADEOS II will provide aerosol measurements thatbenefit from its polarization sensing capability. SeaWiFS and MODIS data products will include both oceancolor and aerosols in regions impacted by African continental outflow over both the Atlantic and IndianOceans, with and without coastal stratus. All these satellite products will require validation over a wide rangeof conditions. SAFARI 2000Õs suborbital measurements will provide many opportunities for such validation.The suborbital measurements will also be essential in extending data outside the satellite overpass times andlocations.

2.1.3. Expected Role of Airborne Sunphotometry in SAFARI 2000. Planning documents for SAFARI2000 have listed airborne sunphotometry as a key measurement, and NASA Ames has requested funding toparticipate with one or both of the Ames Airborne Tracking Sunphotometers (AATS-6 and/or AATS-14; seeAppendix A and Russell, 1999). Furthermore, the University of Washington is funded to install a port in itsCV-580 (Section 2.1.1) to accommodate AATS-14, and Ames has held preliminary discussions with SouthAfrican scientists regarding flying AATS-6 on the South African Aero Commander. However, budgetsavailable within the NASA Radiation Sciences Program and EOS instrument teams (e.g., MODIS) are notadequate to cover the kinds of analyses described in this proposal. Indeed, those budgets, if available, canprobably cover only the costs of (1) essential pre- and/or post-mission AATS calibrations and minorinstrument upgrades, and (2) acquiring AATS transmission data on SAFARI flights and reducing a subset toaerosol/cloud optical depth spectra (0.38-1.02 µm or 0.38-1.56 µm). With proper quality control andancillary SAFARI 2000 data, that AATS data set would provide the raw material to address the science goalsof this proposal when used in the range of modeling, algorithm development, analysis, and validation studiesdescribed in Section 3. Therefore, this proposal requests funding from MDAR (EOS/IDS and/or ACMAP)for such studies. Here we sketch the measurements and analyses possible, with examples from recent studiesusing AATS-6 and Ð14 data.

Airborne sunphotometer measurements flown along transects near the land or ocean surface in SAFARI 2000can provide aerosol optical depth spectra useful for validating products from simultaneous satelliteoverflights. This is illustrated in Figure 1, which shows a comparison of airborne sunphotometer (AATS-6),AVHRR, and ATSR-2 data acquired in TARFOX over the Atlantic Ocean when the UW C-131A flew acrossa gradient of aerosol optical depth between latitudes 37-39 N (Veefkind et al., 1999). The flight path waschosen using half-hourly GOES images to locate the aerosol gradient. Comparing Figures 1a and 1b showsthat the ATSR-2 retrieval reproduces the sunphotometer-measured optical depth gradient better than theAVHRR retrieval. Comparing Figures 1c and 1d shows how the ATSR-2 retrieval also matches thesunphotometer-determined Angstrom exponent better than AVHRR.

Figure 2 shows other comparisons from TARFOX, when AATS-6 on the UW C-131A underflew the MODISAirborne Simulator (MAS) on the NASA ER-2 (Tanre et al., 1999). These comparisons focus on thewavelength dependence of optical depth and illustrate how the magnitude of optical depth affects the successof the MAS retrieval. Specifically, the good agreement in wavelength dependence and magnitude obtainedwhen optical depth is relatively large (>0.2 for λ<1 µm) degrades when optical depth decreases below ~0.05(causing MAS-measured radiance from the aerosol to decrease relative to that from the ocean surface).Establishing such limits and uncertainties is a major reason for validation studies. In SAFARI 2000 theycould be conducted for a variety of smoke and haze types and conditions, over different types of land surfaces(e.g., densely vs. sparsely vegetated), the ocean, and on transects spanning land and ocean.

Figure 3 illustrates how a change in aerosol type can affect the validity of satellite retrievals. Specifically,Figure 3a shows the good agreement between AVHRR and sunphotometer optical depths obtained frequentlyin ACE 2 when the aerosol was confined to the marine boundary layer; Figure 3b shows how this agreementdegrades when an elevated layer of Sahara dust is present. Possible reasons for this degradation includedifferences between the wavelength-dependent single scattering albedos and phase functions of the Saharadust and those assumed in the AVHRR retrieval (Durkee et al., 1999; Livingston et al., 1999; Schmid et al.,1999), plus the height of the absorbing dust aerosols (e.g., Quijano et al., 1999). In Safari 2000,

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sunphotometer underflights of different types of smoke and haze (e.g., biomass burning vs. industrialemissions) could provide analogous tests of the validity of satellite products as a function of aerosol type.Vertical profile flights by the sunphotometer aircraft (e.g., the UW CV-580) would provide simultaneous insitu data on aerosol physicochemical properties, helping to complete the picture.

Figure 4 illustrates the ability of the airborne sunphotometers to measure vertical profiles of multiwavelengthaerosol optical depth and extinction during such aircraft profiles. The case shown, obtained in ACE 2,documents an elevated layer of Sahara dust (~2-3.5 km asl) overlying a very clean layer (~1-2 km asl) and amoderately polluted marine boundary layer (<~1 km asl). Note that the wavelength dependence of extinctionis very different in the marine and Sahara layers, with extinction nearly independent of wavelength between380 and 864 nm in the Sahara layer, owing to the relatively large particles there. In SAFARI 2000 the strongatmospheric stratification associated with the South African anticyclonic gyre is expected to cause manyoccurrences of analogous layering, with different layers often having different sources and characteristics.Airborne sunphotometry combined with simultaneous in situ physicochemical-optical measurements willprovide a rich data set for modeling such diverse, vertically structured aerosols and understanding theirimpact on satellite retrievals.

Closure studies that examine the degree of consistency between sunphotometer measurements, in situmeasurements, and the models that link them are an important source of information on the strengths andweaknesses of the examined measurement and modeling techniques. A typical result from such a closurestudy is shown in Figure 5. The data were obtained in ACE 2 when the Pelican aircraft ascended through amarine boundary layer, carrying AATS-14 and a variety of in situ samplers. The optical depth spectrumlabeled ÒCaltech OPCÓ was obtained by combining in situ size spectra with refractive index models obtainedfrom size-resolved chemical composition measurements at a nearby surface site (which were consistent withsize-integrated chemistry measured on the aircraft). The optical depths labeled ÒNeph+PSAPÓ were obtainedby combining nephelometer measurements of aerosol light scattering (at 1 or 3 wavelengths) with absorptionmeasurements from an absorption photometer.

The result in Figure 5 is typical in that the optical depth spectrum measured by sunphotometer (AATS-14)exceeds that calculated from the in situ measurements. Although some of the error bars overlap (e.g., theOPC-derived optical depth bars with the others), the fact that sunphotometer-measured optical depths nearlyalways exceed in situ derived optical depths in ACE 2, TARFOX, and other comparisons (e.g., Clarke et al.,1996; Hegg et al., 1997; Hartley et al. 1999; Kato et al., 1999; Remer et al., 1997) points to a systematicphenomenon that bears explaining. Possible reasons include (1) loss of semivolatile aerosol material (e.g.,organics) during in situ sampling that is not accounted for in the in situ analyses (e.g., Eatough et al., 1996),and (2) light absorption by a gas on the sunphotometer viewing path that is not accounted for in thesunphotometer analyses (e.g., Halthore et al., 1998). Explaining this persistent difference could havefundamental implications for our understanding of aerosol properties and/or radiative transfer. SAFARI 2000should present excellent opportunities for studying this question, especially on the UW CV-580, which willcarry enhanced instrumentation for measuring organic aerosols (e.g., Eatough et al., 1996) and spectral fluxradiometers (Pilewskie et al., 1998) that can help to distinguish aerosol absorption from gas absorption.

Another type of closure study relating in situ and sunphotometer measurements compares in situ sizedistributions with those retrieved from sunphotometer optical depth spectra. Such a comparison is shown inFigure 6. Within the optically effective diameter range (~0.22 to 8 µm) the AATS-14 retrieved distributionreplicates the main features of the in situ distribution, although for some diameters (~0.7 to 3 µm) the AATS-14 retrieved distribution exceeds the in situ values. This exceedence is in accord with the systematicdifference between sunphotometer and in situ optical depth spectra noted above.

The size distribution retrieval in Figure 6 used a refractive index model based on ACE 2 marine boundarylayer aerosol chemistry, combined with the constrained linear inversion program of King et al. (1978). In theproposed research (Section 3) new aerosol optical models appropriate to the South African aerosols will bedeveloped and used both in the King inversion procedure and in a new procedure based on the recent resultsof Remer et al. (1998a) regarding persistent features of multimodal aerosols (see Sections 3.1.1 and 3.1.4).

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Water in both vapor and condensed phases has a strong influence on radiative transfer and on aerosol size andcomposition. Given the strong stratification present in the South African gyre, as well as the horizontalcontrast in water vapor sources among continental and marine parts of airmass trajectories, one can expectimportant variations in water vapor and associated aerosol changes in SAFARI 2000. The ability of AATS-6and AATS-14 to measure water vapor and aerosols simultaneously on a common viewing path should beuseful in this regard. This ability is illustrated in Figure 7, which compares an AATS-14 water vapor profileto simultaneous in situ measurements. Figure 8 shows a scatter plot comparing AATS-6 water vapor columnswith those obtained by integrating radiosonde profiles in ACE 2. The rms difference, 0.10 g cmÐ2 over arange of 1.5 to 3.3 g cmÐ2, is typical of other comparisons we have made. For example, in the fall 1997 WaterVapor Intensive Observation Period (IOP) of the Atmospheric Radiation Measurement (ARM) program,AATS-6 water vapor column retrievals agreed within 0.11 g cmÐ2 with results from the Global PositioningSystem (2 locations), 3 microwave radiometers, radiosondes, and two other sunphotometers. The range ofwater vapor column amounts during the IOP was 1 to 5 g cmÐ2.

SAFARI 2000 planning documents stress the importance of realtime or quick-turnaround data analyses andopen data access as means of maximizing the scientific return from the measurements. Both AATS-6 andAATS-14 have demonstrated this in previous campaigns like TARFOX and ACE 2, where they producedrealtime color plots of aerosol optical depth spectra that were used in flight direction and planning, as well asin daily science team meetings (which included comparisons to satellite products). With adequatepreparation, this capability could be extended in SAFARI 2000 to include realtime or quick-turnarounddisplays of water vapor and ozone overburdens, as well as of the effective radius, volume, and/or mass of theoverlying aerosol column. The latter would be useful for observing the evolution of aerosol size when, forexample, following a plume downwind, or for mapping cross-plume column masses. Acquiring analogousplume-integrated sizes and masses with in situ sensors would require time-consuming vertical profiling (thusreducing time available for horizontal surveys) and would subject the aerosols to the sampling challenges thatare especially difficult on a vertically profiling aircraft. Providing the above-described realtime displaysrequires the development and testing of algorithms before the campaign, as described in Sections 3.1.1-3.1.4.

SAFARI 2000 plans include an ER-2 lidar to measure vertical profiles of aerosol backscatter, sometimes incoordination with vertical profile flights by the UW CV-580. This will permit comparisons between AATS-14 extinction profiles (like those shown in Figure 4) and backscatter and/or extinction profiles from the lidar.Both AATS-6 and AATS-14 have participated in such comparisons previously. In ACE 2, for example,Schmid et al. (1999) and Welton et al. (1999) compared lidar and airborne sunphotometer profiles in a Saharadust layer over the Izana observatory in the Canary Islands. They got good agreement when the lidar analysisused a backscatter-to-extinction ratio derived from simultaneous ground-based sunphotometry. In TARFOX,Redemann et al. (1999a) derived best-fit complex refractive indices in aerosol layers by comparingsimultaneous profiles of backscatter from an ER-2 lidar profile with profiles of extinction and relative sizedistribution from AATS-6 and optical particle counters on the UW C-131A. By combining the best-fitcomplex refractive indices with the relative size distribution profiles, Redemann et al. (1999b) then producedprofiles of aerosol single scattering albedo (SSA). Figure 9 shows an example result, compared to the SSAprofile obtained by Hartley et al. (1999) using simultaneous measurements of aerosol scattering, absorption,and scattering humidification factor.

Combining airborne sunphotometer optical depth profiles with radiative flux profiles is a potentially powerfulway to determine the absorption properties (hence SSA) of the ambient aerosol, unperturbed by samplingprocesses. This is illustrated by the TARFOX results shown Figure 10 (Russell et al., 1999b). The datapoints show the aerosol-induced decrease in downwelling solar flux measured by pyranometers on the UK C-130 during two descents into aerosol layers over the Atlantic Ocean, plotted versus broadband aerosol opticaldepth derived from occulted pyranometer measurements. (The absorbing gas and Rayleigh components havebeen removed from both the flux change and the optical depth using, e.g., concurrent water vapormeasurements.) The curves show calculations of the expected flux change, based on aerosol sizedistributions retrieved from AATS-6 sunphotometer measurements on the UW C-131A, a real refractiveindex spectrum for aqueous sulfate, and a range of imaginary refractive indices giving the midvisible single-scattering albedos ω(550 nm) shown. Comparing the data points and curves shows that the best-fit value ofω(550 nm) is ~0.9; chi-square analyses using the error bars on the pyranometer optical depths and flux

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changes (the cross in Figure 10) yield ω(550 nm)=0.895±0.025 and 0.905±0.045 for July 25 and 27,respectively.

In SAFARI 2000 the UW CV-580 will be carrying Solar Spectral Flux Radiometers (SSFR, Pilewskie et al.,1998), which, together with the AATS-14 optical depth measurements (380-1558 nm), will permit muchimproved flux change studies. The spectral resolution of SSFR and AATS-14 will permit the type of fluxchange analysis shown in Figure 10 to be accomplished in a wide range of narrow (5 nm) spectral bands.This will permit, for example, solving for SSA as a function of wavelength. It will also aid in identifyingabsorption features that might be due to unknown gas spectroscopy, rather than aerosols. And it will help toidentify artifacts that might be caused by cloud fragments or surface albedo effects. The measurements inFigure 10 were made over the ocean during a cloud-free period to minimize such effects. This will be done inSAFARI 2000 also; however, the fine spectral resolution in the SSFR flux measurements may allow themeasurements to be extended over a uniform land surface, and may also allow some relaxation in the cloud-free criterion. This will be investigated. These types of measurements will also be carried out when anabsorbing aerosol is carried over a uniform stratus deck; the underlying cloud reflectivity maximizes aerosolabsorption in such a case. Biomass smoke outflow over Namibian coastal stratus in SAFARI 2000 couldprovide such an opportunity.

Figure 11 shows a final example of how our sunphotometer data have been combined with satellite data toestimate regional aerosol effects on radiation budgets, as could also be done in SAFARI 2000. The aerosol-induced flux changes shown in Figures 11a-e and 11g were obtained by combining seasonal maps ofmidvisible aerosol optical depth from AVHRR/NOAA (Husar et al., 1997) with aerosol intensive propertiesdetermined in TARFOX (specifically, a relative size distribution derived from a typical AATS-6 optical depthspectrum, an aqueous sulfate real refractive index (~1.38 at 550 nm) and an imaginary refractive index (-0.01)that yielded the best-fit single-scattering albedo of 0.9 in Figure 10). In Figures 11f and 11h a nonabsorbingaerosol is assumed, to show the sensitivity of the results to single scattering albedo. In SAFARI 2000analogous estimates of regional radiative flux changes could be calculated, but with considerably improvedcapabilities. MODIS, MISR, and POLDER optical depths, plus the TOMS aerosol index, should all beavailable over land (unlike the AVHRR optical depths which are restricted to the oceans). And improvedinformation on wavelength-dependent aerosol absorption should be available from the combination ofspectral fluxes and optical depths (SSFR and AATS-14) on the UW CV-580 mentioned above (not to mentionpotential improvements in the in situ measurements).

2.2 African Dust Plume and Water-Leaving Radiance Opportunities on SAFARI 2000 Transits

Transit flights by the UW CV-580 from the US to Africa and back before and after the August-September2000 SAFARI campaign can provide valuable opportunities for measuring the Sahara dust plume andstudying its effect on satellite-derived water-leaving radiance, as well as its relationship to TOMS aerosol andozone products. A stopover in the Cape Verde Islands (~16 N, 22 W), currently planned by UW, wouldprovide an excellent base for such measurements, since the islands are near the location of maximum dustoptical depth in the August-September season. Plume underflights across the gradient (cf. Figure 1), frommaximum to minimum optical depth, would provide a test of satellite atmospheric-correction algorithms overa wide range of difficulty. Vertical profiles through the layer (cf. Figure 4) would show the relative altitudesof attenuation by aerosols, Rayleigh, water vapor, and ozone. Flights within the elevated dust layer wouldprovide important in situ measurements for closure studies (cf. Figures 5 and 6) and detailed characterizationof the dust aerosols.

2.3 ACE Asia Survey and Evolution Component (AA-SEC)

2.3.1 ACE Asia Goals and Overall Approach. The Asian Pacific Regional Aerosol CharacterizationExperiment (ACE Asia) is the fourth in a series of aerosol characterization experiments organized by theInternational Global Atmospheric Chemistry Program (IGAC). Each ACE is designed to integrate suborbitaland satellite measurements and models so as to reduce the uncertainty in calculations of the climate forcingdue to aerosol particles (Huebert et al., 1999). ACE Asia focuses on aerosol outflow from Asia to the Pacificbasin because (1) Asian anthropogenic emissions and mineral dust are very different from the environments

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of previous ACE experiments, and (2) Expected increases in Asian emissions have the potential to cause largechanges in radiation budgets, cloud microphysics, and hydrological output over the coming decades.

The goals of ACE-Asia are to determine and understand the properties and controlling factors of the aerosolin the anthropogenically modified atmosphere of Eastern Asia and the Northwest Pacific and to assess theirrelevance for radiative forcing of climate (Huebert et al., 1999). Subsidiary objectives are to:

1. Determine the physical, chemical, and optical properties of the major aerosol types in the Asian Pacificregion, determine their state of mixing, and investigate the relationships among these properties.

2. Quantify the physical and chemical processes controlling the evolution of aerosols in the Asian Pacificregion and in particular their physical, chemical, and optical properties.

3. Evaluate numerical models which will extrapolate aerosol properties and processes from local to regionaland hemispheric scales, and assess the regional direct and indirect radiative forcing by aerosols in theAsian Pacific region.

ACE Asia will include a network of ground stations operated over the 2000-2004 timeframe, with intensive,multiplatform field studies to focus on specific objectives. The Survey and Evolution Component (AA-SEC)is the first of the ACE Asia intensive field studies, and the only one for which a written proposal (Huebert etal., 1999) has been developed. Planned for March-April 2001, AA-SEC is designed to answer a series ofquestions, which can be grouped as follows (Huebert et al., 1999):

Aerosol Survey (What are the vertical and regional distributions of aerosol concentrations and propertiesunder various meteorological conditions?)

A. What are the relative size-dependent contributions of sulfate, nitrate, carbonaceous material, sea salt,primary anthropogenic particles, and dust to the optical properties (absorption, total and angular scattering)of aerosols?

B. How do the interactions between these species (their state of mixing) affect their optical properties?C. How are the distributions affected by specific meteorological events?

Aerosol Evolution (How do aerosol properties evolve as they move offshore?)

D. How do aerosol properties and process rates evolve with time (distance) over the ocean?E. What are the lifetimes or removal rates of particles?F. What is the rate of exchange of particles and precursor gases between the free troposphere, buffer layer,

and boundary layer?

Aerosol Interactions with Gas-Phase Atmospheric Chemistry (What role does the atmospheric chemistry ofthe Asian-Pacific region play in influencing aerosol properties and evolution, and likewise, how does theAsian aerosol affect tropospheric chemistry in the region?)

G. How does mineral dust interact with atmospheric gas-phase chemistry?H. How does sea salt interact with gas-phase chemistry?I. How does the anthropogenic/urban aerosol interact with gas-phase chemistry?

The AA-SEC omnibus proposal to NSF (Huebert et al., 1999) describes a plan to address these questionsusing three US mobile platforms (the NCAR C-130, the CIRPAS Twin Otter, and a NOAA or UNOLS ship)and 1-2 enhanced ground stations working in coordination with ships, aircraft, lidars, and surface sites from avariety of nations (e.g., Japan, Korea, China, and Taiwan). The operations base will probably be located insouthern Japan. Satellites will be used both for experimental planning (such as locating dust layers) and forextrapolating results over larger scales. AA-SEC will survey concentrations and properties vs. altitude andlocation, and it will conduct Lagrangian experiments, in which repeated flights are made into a taggedairmass for 1-2 days, to improve process models, identify reaction pathways, and quantify rates. Efforts will

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be made to coordinate some AA-SEC flights with the NASA TRACE-P program, which will be focusing onphotochemistry in Asian outflow at about the same time, using measurements on the NASA DC-8 and P-3. Ifpossible AA-SEC will coordinate some observations with an airborne simulator for the PICASSO-CENAspaceborne lidar.

2.3.2 Satellite Data Products Relevant to AA-SEC. As in previous ACEs, satellite data products will beused both in realtime to plan and direct flights and for post-campaign analyses. For example, in AA-SECflights to study the plumes of desert dust emanating from Asia, satellite observations will be used to identifylocations of maximum dust concentrations and areas where concentration gradients can most easily bestudied. In Lagrangian experiments that study aerosol evolution, satellite observations of the decay ofbackscatter by the continental plume will be used to identify regions where removal mechanisms seemespecially effective. As in SAFARI 2000, the availability of MODIS, MISR, and MOPITT on EOS Terra willprovide new capabilities that will help address the goals of AA-SEC (e.g., Table 1); at the same time, AA-SEC will provide new conditions and data sets with which to validate Terra and other satellite data products.As an example of the latter, the yellowish soil dust aerosol layers emanating from Asia are known to havedifferent spectral absorption characteristics than the red-brown Sahara dust; however, these differences arenot well quantified. AA-SEC measurements during yellow dust plume events should provide important newvalidation data sets for TOMS aerosol and ozone products, and for water-leaving radiance products fromSeaWiFS as well as MODIS. Many of the other validation opportunities provided by AA-SEC are analogousto those described in Section 2.1.2 for SAFARI-2000 (albeit with different aerosols); for brevity the reader isreferred to Section 2.12.

2.3.3 Expected Role of Airborne Sunphotometry in AA-SEC. The AA-SEC Science and ImplementationPlan (Huebert et al., 1999) specifies aerosol optical depth measurements as part of the minimum requirementfor both surface and airborne platforms, and it includes an Ames tracking sunphotometer as part of theÒHighest Priority Ð EssentialÓ payload for the NCAR C-130 and part of the recommended payload for theTwin Otter. Some of the reasons for these inclusions are summarized below. However, it is important to notethat the one budget identified so far for possible support of the AA-SEC airborne sunphotometermeasurements (the NOAA Global Aerosols Program) is inadequate to support the type of interdisciplinary,integrated analyses described in Section 3 of this proposal. The NOAA budget, if obtained, would probablycover only the costs of (1) essential pre- and/or post-mission AATS calibrations and upgrades, and (2)acquiring data on AA-SEC flights and reducing a subset to aerosol/cloud optical depth spectra. The Amessunphotometer team is ineligible for NSF funding. Therefore, this proposal requests MDAR funding for theintegrated modeling and analyses described in Section 3, based on the following expected role of airbornesunphotometry in AA-SEC.

The AA-SEC Science and Implementation Plan (Huebert et al., 1999) includes a variety of schematic C-130and Twin Otter fight plans, each designed to address specific questions from the list above. For example,they include flights at several altitudes across the edges of elevated dust layers and upwind and downwind ofurban-industrial plumes. Some flight patterns include legs with the Twin Otter flying near the surface under aplume while the C-130 overflies the plume with a downward-looking lidar. When such a leg spans thegradient from plume core to edge during a satellite overpass, AATS optical depth spectra measured from theTwin Otter would provide validation data for comparisons such as those in Figures 1-3. At the same time theAATS data could provide a test of the backscatter-to-extinction ratios and other assumptions used to deriveoptical depths from the C-130 lidar. Such comparisons could be a valuable precursor to validation flights forPICASSO-CENA conducted after its launch (scheduled for 2003). AA-SEC flight plans also call for theTwin Otter to ascend from near the surface through the aerosol layers aloft while collecting in situ data onaerosol size distribution, chemistry, light scattering and absorption. This would yield AATS vertical profilesof multiwavelength extinction (as in Figure 4) for comparison to lidar profiles (as was done, e.g., in ACE 2 bySchmid et al., 1999; and Welton et al., 1999). It would also yield the in situ measurements needed for closurestudies, such as those illustrated by the ACE 2 results in Figure 5. Comparisons of the profiles ofsunphotometer extinction, lidar backscatter, and in situ size distribution can yield best-fit values of complexrefractive index and single-scattering albedo for each sampled layer, as demonstrated by Redemann et al.(1998, 1999a,b) with PEM-West and TARFOX measurements. These values could be compared to singlescattering albedos from the in situ scattering and absorption measurements (e.g., Figure 10) and to complex

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refractive indices from the in situ chemistry measurements, taking into account the local humidity and effectsof aerosol hygroscopicity.

Sunphotometer-derived column or layer size distributions could be validated by comparisons to in situ datafrom profile flights (as, e.g., in Figure 6), and used when underflying plumes to document changes inoverlying aerosol effective radius, surface area, and mass. This information should be valuable in aerosolevolution studies (e.g., to see whether sedimentation modifies the dust size-distribution in a predictable way)and reduce the need for aircraft profiles, which take flight time away from horizontal legs. However, derivingaccurate information on aerosol size, surface area, and mass from sunphotometer optical depth spectrarequires algorithms that incorporate size-dependent effective refractive indices that are appropriate to theaerosol on the sunphotometer viewing path. Development of such algorithms is discussed in Section 3.Incorporation of simultaneous AATS data on water vapor will be investigated as a means of accounting forpossible humidification effects on refractive index (which will be different in sulfate layers and dust layers,for example).

2.4 Other Possible ExperimentsIn addition to SAFARI 2000, its transit flights, and ACE Asia, there are other experiments being consideredor planned for CY 2000 and 2001 in which our airborne sunphotometers may participate. If this occurs, theresulting data sets would be made available to the modeling and data analysis studies proposed here. Anexample of such a study is the Florida/Caribbean Dust study being considered for Summer 2000. This jointNavy/NASA study would investigate the African dust carried over the Caribbean and Florida by using acombination of aircraft, satellite and surface measurements. We have been approached about the possibilityof participating with AATS-6 or AATS-14 on the Navajo aircraft and are interested; however, thesemeasurements are not yet funded. Another possibility is operating AATS-6 or AATS-14 on the NASA P-3during the TRACE-P study of the impact of Asian emissions on atmospheric chemistry in the Pacific Basin.TRACE-P is planned for March and April 2001 and would thus coincide, and possibly coordinate with ACEAsia SEC. We are considering proposing to operate AATS-6 or AATS-14 on the P-3 in TRACE-P, toprovide satellite validation data and enhance aerosol chemical-physical-optical closure studies and trace gasphotochemical studies. However, our decision to propose will depend on the experiment definition in theTRACE-P NRA, the potential collaborations with other TRACE-P scientists, and available budgets.

3 PROPOSED RESEARCH

3.1 Year One

3.1.1 Task 1.1: Optical Modeling of Smokes and Other Aerosols Expected in SAFARI 2000. Theobjective of this task is to produce models that reflect the size-dependent chemical composition and mixingstate of the various SAFARI 2000 aerosols (e.g., biomass smokes, industrial and biogenic aerosols) and canbe used to forward-calculate single-particle extinction kernels and extinction spectra for specified sizedistributions. Such models are needed by algorithms that retrieve size distributions and other properties fromsunphotometer extinction or optical depth spectra (see Task 1.4 below). When extended to calculatescattering phase functions, they can also be used in algorithms that retrieve optical depth from satellite-measured radiances and in calculations of aerosol-induced radiative flux changes. In TARFOX relativelysimple models were developed for this purpose, assuming size-independent homogeneous internal mixturesof sulfate, organics, black carbon, and water (Hignett et al., 1999) or just sulfate, black carbon and water(Russell et al., 1999b). In ACE 2 ground-based measurements of size-resolved chemical composition(including three forms of sulfate, organic and elemental carbon, sea salt, water, and soil dust) were used todevelop models of boundary-layer and dust-layer aerosols that used a combination of internal and externalmixing, all assuming homogeneous spheres (Collins et al., 1999). Recently our group has begun using shell-and-core calculations to model black carbon inclusions in sulfate aerosols (Redemann et al., 1999c), includingthe effect of hygroscopic growth on light absorption and single scattering albedo. In this task we will extendour previous models to include biomass smoke aerosols and others expected and/or found in the SAFARI2000 area. Information on biomass smoke aerosols will be obtained from published results on Brazilianbiomass smokes measured in SCAR-B (e.g., Dubovik et al., 1998; Kaufman et al., 1998; Martins et al., 1998;

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Remer et al., 1996, 1998b; Reid et al., 1998a,b,c; Yamosoe et al., 1998), on African savanna smokesmeasured in SAFARI 92 (e.g., Andreae et al., 1998; Le Canut et al., 1996) and on both measured in TRACE-A (e.g., Anderson et al., 1996). This will include the shell-and-core and discrete diploe approximation resultsof Martins et al. (1998) used to represent soot inclusions and packed soot clusters.

3.1.2 Task 1.2: Ozone-Aerosol Separation Algorithm Refinement and Simulations. The objective of thistask is to optimize the AATS-14 ozone retrieval algorithm for the aerosol and ozone conditions expected inSAFARI 2000 and to simulate its performance under those conditions. Our current operational AATS-14ozone algorithm uses the Chappuis-band quadratic fitting technique described by King and Byrne (1976) andpreviously applied by one of us (B. Schmid) to the University of Bern 18-Channel Tracking Sunphotometer,as well as by Michalsky et al. (1995) to rotating shadowband radiometer measurements. We use this ozone-aerosol separation algorithm primarily to improve the accuracy of aerosol optical depth spectra in theChappuis-band region (~500-750 nm; cf. Figure 12) when ancillary data on ozone column contents (e.g., fromTOMS) are not available. However, in the proposed research it may prove useful to compare the TOMSaerosol index (obtained from measurements at 340-380 nm) and TOMS column ozone (obtained from theHartley-Huggins band, ~300-340 nm) to independently derived AATS-14 aerosol optical depth spectra (380-1558 nm, Figure 12) and column ozone (from Chappuis-band absorption). Also, when enhanced troposphericozone layers are present above strong aerosol layers in SAFARI 2000 (as observed, e.g., in TRACE-A byBrowell et al., 1996), sunphotometer ozone column retrievals obtained while flying transects above mostaerosol optical depth but below the tropospheric ozone peak may be able to reveal tropospheric ozone spatialstructure that has finer horizontal scale than the overlying stratospheric ozone. This may prove useful sincecurrent SAFARI 2000 plans do not include an airborne ozone lidar. Therefore, in this task we will investigatepossible refinements to our AATS-14 ozone retrieval algorithm, and we will simulate its performance withaerosol and ozone horizontal and vertical structures expected in SAFARI 2000, based on ozone and aerosolresults from SAFARI 92 and TRACE A (e.g., Anderson et al., 1996; Browell et al., 1996; Chatfield et al.,1996)

One possible refinement we will investigate is use of a SAGE III-like least squares technique (Russell et al.,1996; Cunnold et al., 1996) for ozone-aerosol separation. We recently compared our current algorithm to aSAGE III-like algorithm as part of our SAGE III Science Team research. The comparison used troposphericdata sets acquired with AATS-14 in the ACE-2 field campaign (Schmid et al., 1999). The algorithms werecompared for a range of aerosol optical depths (0.008 < τa(500 nm) < 0.4), sampled by flying AATS-14 ataltitudes from sea level to 3.6 km. Ozone column amounts were about 300 Dobson Units (DU), whichproduced an ozone optical depth of about 0.04 at the Chappuis peak near 600 nm. The least-squares techniqueuses a matrix-inversion structure like that used for SAGE II [i.e., Eqs. (17)-(19) of Chu et al. (1989)] andSAGE III [Eqs. (3.2.2.6)-(3.2.2.8) of Russell et al. (1996)], with transmissions measured at AATS-14wavelengths 380, 453, 500, 525, 605, 667, 779, 864, and 1558 nm (cf. Figure 12). Results to date show thatthe two algorithms produce ozone values that agree within about 5 DU for τa(500) < 0.01 and within 10 DUfor 0.01 <τa(500) < to 0.07. However, differences can approach or exceed 100 DU when τa(500) > 0.3.

Steele and Turco (1997) and Cox (1998) have shown that the accuracy of ozone-aerosol separation via least-squares techniques can be sensitive to the coefficients used to express aerosol extinction at an ozone-sensitivewavelength (e.g., 600 nm) in terms of aerosol extinction at ozone-insensitive or less-sensitive wavelengths(e.g., 1020 and 453 nm). They show how different choices of these coefficients are more or less appropriatedepending on the typical range of aerosol size distributions present during the measurements (e.g., theyconsider a wide range of prevolcanic and postvolcanic stratospheric sulfate aerosols). However, it is alsoimportant to consider the sensitivity of derived ozone and aerosol products to measurement error. Thissensitivity is also dependent on the choice of the above coefficients. Thus the choice of the ÒbestÓcoefficients must carefully consider both typical measurement errors at each wavelength and the typical rangeof aerosol characteristics (e.g., size distributions and compositions) likely to be encountered. This range isconsiderably wider in the troposphere than in the stratosphere. Therefore in this task we will use thetropospheric data sets from ACE 2, SCAR-B, SAFARI 92, and TRACE-A mentioned above, plus the aerosoloptical models developed in Task 1.1, to investigate the best forms of least-squares techniques for separatingozone and aerosols in AATS-14 data sets.

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A primary determinant of the accuracy of ozone-aerosol separation in the vicinity of 600 nm is the relativesize of ozone and aerosol line-of-sight optical depths there. For example, a typical stratospheric ozone opticaldepth at 600 nm is only ~0.05 (cf. Figure 12). Hence, when midvisible aerosol optical depths exceed about0.2, retrieved ozone amounts become very sensitive to aerosol extinction estimated at 600 nm from otherwavelengths; consequently, the retrieved ozone amounts have large uncertainties. These uncertainties can bemarkedly reduced by flying the sunphotometer to higher altitudes, where aerosol optical depth is less. Theusefulness of this approach in SAFARI 2000 for getting information on tropospheric ozone columns willdepend on whether there is significant tropospheric ozone above the strong aerosol layers. Therefore, in thistask we will use ozone and aerosol results from SAFARI 92 and TRACE A (e.g., Anderson et al., 1996;Browell et al., 1996) as inputs to simulations of AATS-14 ozone retrievals in vertical profiles from thesurface to the top of the tropospheric aerosol layers. The results of Browell et al. (1996) showing thatsometimes there are large tropospheric ozone concentrations above the tropospheric aerosols is encouraging.Nevertheless, the simulations may show that the frequency of occurrence of such conditions will not oftenlead to successful Chappuis-band retrievals of tropospheric ozone features with AATS-14 in SAFARI 2000.In this case we will also look at the desirability and feasibility of replacing some of the aerosol channels inAATS-14 with channels in the Hartley-Huggins ozone band.

3.1.3 Task 1.3: Water Vapor Retrieval Refinement. Schmid et al. (1996) reported a comparison ofmodeling (using LOWTRAN7, MODTRAN3, FACSODE3P and the Thomason (1985) Model) and empiricalapproaches to retrieve columnar water vapor from ground-based sunphotometers. More recently, Halthore etal. (1997) emphasized the improved performance achievable by using a bandwidth of 10 nm or less for the940-nm filter and by using MODTRAN3 for water vapor absorption calculations. And very recently, Giver etal. (1999) reported errors in the HITRAN data base (used by MODTRAN) for certain lines in the 940-nmband (cf. Figure 12), showing that the HITRAN line strengths are 14.4% too small. If this error applies to alllines in the 940-nm band, water vapor columns retrieved from measured band transmittances would be about14% too large. As noted in Section 2.1.2, previous comparisons of our AATS-6 and AATS-14 water vaporretrievals (which use MODTRAN 3.5 v 1.1) to results from radiosondes, airborne in situ measurements,Global Positioning System retrievals, microwave radiometers, and other sunphotometers under a wide rangeof water vapor columns (1 to 5 g cmÐ2) have yielded typical agreement within 0.1 g cmÐ2 (cf. Figures 7 and 8),which suggests that any systematic bias in our retrievals caused by erroneous line strengths is less than 14%.Nevertheless, the fact that AATS retrievals in the Fall 1997 Water Vapor Intensive Observation Period (IOP)were ÒwetterÓ than the average suggests that we perform a review of the latest spectroscopy available for the940-nm band and make any necessary revisions to our AATS water vapor retrieval algorithm. We will do soin this task.

3.1.4 Task 1.4: Aerosol Column Size Distribution and Mass Retrieval Algorithm Development. Theobjective of this task is to produce algorithms, tailored to the aerosols expected in SAFARI 2000, that retrieveaerosol column size distribution, effective radius, surface area, volume, and mass from AATS-6 and AATS-14 optical depth or extinction spectra (380-1020 nm and 380-1558 nm). An example of a size distributionretrieved from an AATS-14 extinction spectrum has been shown in Figure 6 (Section 2.1.3). That retrievalused the constrained linear inversion program of King et al. (1978) and assumed internally mixedhomogeneous spherical aerosols with a complex refractive index consistent with the chemical composition ofthe polluted marine boundary layer in the ACE 2 area. An advantage of the King et al. technique is that itmakes no assumption about the mathematical form of the retrieved size distribution. However, it usuallyrequires some human intervention in judging the best radius limits, smoothing parameter values, anditeration-averaging procedures, each of which is influenced by the nature of the aerosol extinction spectrumbeing inverted. Hence, it is not well suited to automated inversion of large volumes of data.

Recently, as part of TARFOX and ACE 2 analyses supported by NASAÕs Global Aerosol ClimatologyProgram (GACP), we developed a retrieval algorithm that is better suited to automated inversions and thatcan also accommodate aerosols with size-dependent chemical composition and, with some restrictions, shell-and-core structures and external or internal mixtures. The technique is based on the findings of Remer andKaufman (1998) that their very large set of Sun/sky radiometer measurements in the US Eastern seaboard fora wide range of aerosol optical depths (0.05 to 0.60 at 670 nm) can be well represented by a linearcombination of 5 lognormal modes, each with a fixed width and central radius value. Moreover, two of the

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modes, identified as coarse and stratospheric (Pinatubo volcanic), also had fixed amplitude (particle numberor volume). Thus, the variability of the best-fit size distribution model resulted entirely from variations in theamplitude of the remaining three modes (called accumulation-1, accumulation-2, and salt). Our new retrievalalgorithm assumes the 5 Remer/Kaufman modes (with the stratospheric mode currently set to zero) and variesthe amplitude of the 3 variable modes to obtain a best fit to our measured AATS-6 and AATS-14 opticaldepth and extinction spectra from TARFOX and ACE 2. Because the algorithm uses a precomputedextinction spectrum for each mode (assuming intensive optical properties from TARFOX and/or ACE 2),best-fit solutions are obtained in a single step via linear least squares, with no need for iteration or humanintervention. It is thus fast and lends itself well to automated retrievals for large volumes of data. To date ithas provided a good fit to all TARFOX or ACE 2 optical depth spectra tried.

Remer et al. (1996; 1998) have found analogous regularities in the multimodal size distributions retrievedfrom their Sun/sky measurements of biomass burning aerosol during SCAR-B in Brazil. Their dynamicaerosol model, which is based on the combined regularities found in Brazil and Eastern US aerosols, is nowused in the spaceborne MODIS algorithm to retrieve aerosol properties over land (Kaufman et al., 1997b;King et al., 1999). In this task we will extend our multimodal retrieval algorithm to include biomass burningaerosols and others expected in SAFARI 2000. The work will use the smoke size modes found by Remer etal. (1996; 1998) for Brazil biomass smokes and will also look at results from SAFARI 92 (cf. Task 1.1) forpossible differences in African smokes and other South African aerosols. Extinction spectra for each modewill be precalculated for a variety of size-dependent chemical compositions based on the SCAR-B andSAFARI 92 results, using refractive indices, shell-and-core structures, and discrete dipole approximationresults from Task 1.1. The resulting algorithms will be built into the AATS-6 and/or AATS-14 dataacquisition computers before the SAFARI 2000 deployment so that results can be displayed in realtimeduring flights or made available for postflight Science Team meetings. This task will also assess the potentialvalue to size distribution retrievals of extending AATS-14Õs longest wavelength from 1558 nm to about 2200nm, especially for the soil dust aerosols to be probed on SAFARI 2000 transit flights and in ACE Asia.

3.1.5 Task 1.5: Quick-Look Analyses and Comparisons to Satellite Data. This task will use the algorithmsdeveloped in Tasks 1.2-1.4 to display in realtime during the SAFARI 2000 deployment (August-September2000) the aerosol column size distribution, effective radius, surface area, volume, and mass, plus water vaporand ozone column amounts, retrieved from AATS-6 and/or AATS-14 optical depth and transmission spectra.The optical depth spectra and retrieved products will be made available in flight and during field ScienceTeam meetings for flight planning and direction. They will also be used for quick-look comparisons towhatever satellite data products are available in the field. In past experiments these have included aerosoloptical depths from AVHRR on NOAA 14, Imager on GOES, and a radiometer on Meteosat. Any analogousquick-look products from EOS Terra MODIS and MISR (including atmospheric corrections for ocean colorand land products), plus TOMS aerosol index and ozone, will be compared to the sunphotometer products inthe field.

3.1.6 Task 1.6: Preliminary Aerosol Radiative Effect Calculations. The goal of this task is to prepare forcalculating radiative effects of SAFARI 2000 aerosols over Africa and surrounding oceans by makingpreliminary calculations that combine pre-SAFARI 2000 satellite data (e.g., 1996-7 results from OCTS andPOLDER on ADEOS, or TOMS aerosol indices) with results from the mixed aerosol optical modelsdeveloped in Task 1.1. Our group has extensive experience in the application of radiative transfer models tothe calculation of aerosol-induced radiative flux changes. For example, Bergstrom and Russell [1999] used ageneralized two-stream model to derive North Atlantic regional aerosol radiative effects (by combiningAVHRR midvisible optical depth fields with intensive aerosol optical propertiesÑsee Figure 11), whileRedemann et al. [1999a] used the Fu-Liou broadband radiative transfer model [Fu and Liou, 1992; Fu andLiou, 1993] to investigate the vertical structure of the direct shortwave aerosol radiative forcing. Similarapproaches will be used in this task.

3.2 Years Two and Three

3.2.1 Task 2.1: Satellite Validation Studies. Extensive comparisons of the type shown in Figures 1-3 will bemade between satellite data products and airborne sunphotometer aerosol optical depth spectra, wavelength

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dependence parameters (e.g., the Angstrom exponent), and water vapor and ozone column contents. Satellitedata expected to be available for this purpose are listed in Table 1. Efforts will focus first on the SAFARI2000 data set (including data from Sahara dust measurements on transits) and later on the ACE-Asia data set.The degree of agreement or disagreement found will be quantified in terms of root-mean-square differencesand mean biases, all as functions of wavelength, aerosol type, and viewing condition (including surface typeand solar and satellite angles). The airborne sunphotometer data will be used to assess the degree ofvariability within satellite pixels (including variations between AERONET and other ground sunphotometersites), which may be particularly important near localized sources like small biomass fires or formeasurements in broken cloud fields. Aerosol models assumed in the satellite retrievals will be compared tothe aerosol models developed in Tasks 1.1 and 2.2, and also to aerosol properties determined from in situmeasurements in each campaign. Where significant differences in assumed and actual aerosol properties arefound, examples of adjusted satellite products will be produced, using the single scattering albedo and phasefunction of the actual aerosols. Possible shape effects for soil dust and sea salt aerosols will be investigated(e.g., Mishchenko et al., 1997; Kahn et al., 1997), as well as effects of the vertical distribution of absorbingand nonabsorbing aerosols (e.g., Clark et al., 1997; Quijano et al., 1999). Implications of these studies will beinvestigated not only for atmospheric products (e.g., aerosols, water vapor, and ozone), but also for oceancolor and land surface products as affected by atmospheric corrections.

3.2.2 Task 2.2: Update of Aerosol Optical Models, Including Mineral Dusts. The aerosol optical modelsdeveloped in Task 1.1 will be updated using the suborbital measurements (e.g., airborne sunphotometer,ground Sun/sky radiometer, air and ground lidar, and in situ chemical, physical and optical) made in SAFARI2000 and ACE Asia. Areas of emphasis will include quantifying characteristic differences between theAfrican (reddish-brown) and Asian (yellowish) soil dust aerosols (e.g., Sokolik and Toon, 1999; Sokolik,1999) and capturing changes that occur during downwind evolution of various aerosols (including dusts andsmokes) as a result of agglomeration of different particles (e.g., soot, sulfates, nitrates), condensation of waterand/or organic vapors, and photochemical reactions outside and inside of clouds. Particular emphasis will beplaced on quantifying the wavelength- and humidity-dependent single scattering albedo of realisticmulticomponent aerosols, since this parameter is so important in determining aerosol radiative impacts onclimate (including top-of-atmosphere forcing, surface forcing, stability changes, and cloud changes). Effectsof shape on scattering phase functions will also be investigated, including characteristic shape changes thatoccur during downwind evolution.

3.2.3 Task 2.3: Aerosol Evolution and Budget Studies. We will combine the algorithms developed in Task1.4 with airborne sunphotometer data acquired while underflying plumes and hazes in downwind andcrosswind transects to study how aerosol sizes and masses evolve during downwind transport, and howvarious sources contribute to regional mass budgets. Efforts will be made to use the airborne sunphotometerwater vapor measurements to estimate the condensed water content of overlying aerosols and thereby choosethe most appropriate aerosol optical property models to use in the algorithms that retrieve size distributionand mass from optical depth spectra. This work will be closely coordinated with modeling studies proposedto ACMAP by Dr. Robert Chatfield of NASA Ames. Those studies will examine the effects ofmeteorological processes (like dry boundary layer lifting and cumulonimbus clouds) in determining trace gasand aerosol budgets in the boundary layer and mid to upper troposphere using MM5 and the GRACES modeltogether with SAFARI 2000 data from MOPITT and lidars, among other sources.

3.2.4 Task 2.4: Aerosol Chemical-Physical-Optical Closure Studies. In addition to the satellite validationstudies in Task 2.1 we plan to conduct many closure studies that evaluate the mutual consistency of thesunphotometer data products, other remote, radiometric, and in situ measurements, and the models that linkthem. Examples include:

¥ Comparisons (as in Figure 5) between optical depth spectra measured by airborne sunphotometer andcalculated from in situ measurements of size distribution, chemical composition (including condensedwater), light scattering, and absorption on the same aircraft profile,

¥ Comparisons (as in Figure 6) between size distributions retrieved from airborne sunphotometer extinctionor optical depth spectra and obtained from in situ measurements (after correcting for such sampling effectsas evaporation, inlet size cutoffs, and composition-dependent calibration factors),

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¥ Comparisons between sunphotometer optical depths and those obtained from lidar profiles using thebackscatter-to-extinction values assumed in the lidar analyses. These backscatter-to-extinction ratios willalso be compared to those derived from in situ measurements and the aerosol models developed in Tasks1.1 and 2.2. Effects of nonsphericity in soil dust and seasalt aerosols will be considered, since lidarbackscatter is sensitive to nonsphericity. These results will be provided to the development of PICASSO-CENA retrieval algorithms.

¥ Comparisons between radiative flux changes measured by SSFRs (Pilewskie et al., 1998) and calculatedfrom simultaneously measured aerosol and gas properties. These comparisons will be analogous to those inFigure 10, with the advantage that both the flux changes (from SSFR) and the optical depths (from AATS-6or Ð14) will be available in narrow wavelength bands. Hence best-fit aerosol single scattering albedosderived from analyses like those in Figure 10 will also be available as a function of wavelength.

¥ Comparisons of aerosol single scattering albedos derived by a variety of techniques, including (1)comparing lidar backscatter, sunphotometer extinction, and in situ size distribution profiles (e.g., Redemannet al., 1999a), (2) combining in situ measurements of aerosol light scattering, absorption, andhygroscopicity (e.g., Hegg et al., 1997; Hartley et al., 1999), (3) flux-change comparisons (e.g., Russell etal., 1999b), and (4) the optical modeling in Tasks 1.1 and 2.2. A comparison of results from techniques (1)and (2) is illustrated in Figure 9.

The above examples are only illustrative. Our experience has been that participation in multiplatform,multiagency campaigns like SAFARI 2000 and ACE Asia presents many opportunities for comparisons andclosure studies, some of which, though very important, were not anticipated in advance. These closurestudies, which typically entail collaborations among several groups using disparate measurement andmodeling techniques, germinate during pre- and post-campaign science team meetings as well as during thecampaigns. We expect that this will be the case during the proposed research.

3.2.5 Task 2.5: Aerosol Radiative Effect Calculations. We will expand on the radiative transfer modelingcarried out in Task 1.6. by incorporating the aerosol optical properties actually measured by satellite duringthe field campaigns (e.g., SAFARI 2000 third campaign [Aug-Sep 2000], ACE Asia SEC [Mar-Apr 2001];see Table 1). In addition, aerosol parameters obtained from the multi-instrument closure studies in Task 2.4and those derived from the advanced mixed aerosol optical models outlined in Tasks 1.1 and 2.2 will be usedto drive the radiative transfer codes. In this manner, the uncertainties in the aerosol radiative effects willbecome smaller as the uncertainties in the aerosol optical properties will be reduced through mutualconsistency (closure) studies.

3.2.6 Task 2.6: Integrated Analyses and Assessments. We expect that these interdisciplinary investigationswill be carried out partly through collaborations among the CoIs and PI of this proposal and partly throughcollaborations with other participants in SAFARI 2000, ACE Asia, and MDAR (EOS/IDS and/or ACMAP).Here we sketch a few examples. The satellite validation studies in Task 2.1 that relate to atmosphericcorrection of ocean color data products will be tightly linked to the algorithms for such products and willentail close collaboration with CoI Kenneth Voss, who coauthored the Normalized Water-leaving Radiance(atmospheric correction) algorithm for MODIS. However, these studies would benefit from collaborationswith investigators who use the ocean color products to study ocean biogeochemical processes, and whotherefore see the biogeochemical implications of changes to ocean color products via revised atmosphericcorrections. Hence we will seek such collaborations through Dr. Voss and Science Team activities. Thesame is true regarding atmospheric correction of land surface products used to study, for example, terrestrialecosystems. Hence we will seek collaboration with concerned ecosystem scientists, e.g., on the MODIS landteam or the SAFARI 2000 team. Our results on smoke plume particle evolution and mass budgets obtainedfrom realtime and post-campaign sunphotometer flights on downwind and crosswind transects of plumes andregional hazes should be of interest to SAFARI 2000 fire scientists who conduct emission, evolution andmass budget studies (e.g., Scholes et al., 1996; Ward et al., 1991, 1993); hence we will seek suchcollaborations on the SAFARI 2000 team.

As noted in Task 2.4 above, not all the important collaborations can be anticipated in advance; nevertheless,the success of our previous collaborations with ecosystem scientists, atmospheric chemists, and others in, e.g.,ISLSCP, HAPEX-Sahel, BOREAS, AASE, TARFOX, and ACE 2 will inspire us to seek them out.

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4 SCHEDULE

CY 2000 CY 2001 CY 2002FY 2000 FY 2001 FY 2002 03Task

No.Task or Event

J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D

1.1 Optical modeling of smokes etc. for SAFARI1.2 Ozone-aerosol algorithm and simulations1.3 Water vapor retrieval refinement1.4 Aerosol column size distrib. & mass alg. devel.1.5 Quick-look analyses and comparisons

- Preparations- Field analyses and comparisons

1.6 Preliminary aerosol radiative effect calculationsSAFARI 2000

- Workshop- Third intensive air/ground campaign- Archiving, meeting presentations, journal specialissues

EOS/IDS plenary program review meetingEOS/IDS disciplinary or ACMAP meeting

2.1 Satellite validation studies2.2 Optical model updates, including mineral dusts2.3 Aerosol evolution and budget studies2.4 Aerosol chem-phys-optical closure studies2.5 Aerosol radiative effect calculations2.6 Integrated analyses and assessments

ACE Asia- Science Team meeting near ops center site- Survey & Evolution Component campaign- Data workshop/Science Team meeting- Archiving, meeting presentations, journal specialissues

J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D

CY 2000 CY 2001 CY 2002

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Quijano, A.L., I.N. Sokolik, and O.B. Toon, Influence of the aerosol vertical distribution on the retrievals of aerosoloptical depth from satellite radiance measurements, in Workshop on Mineral Dust, edited by I.N. Sokolik, Boulder,CO, 1999.

Redemann J., R. P. Turco, R. F. Pueschel, M. A. Fenn, E. V. Browell, W. B. Grant, A multi-instrument approach forcharacterizing the vertical structure of aerosol properties: case studies in the Pacific basin troposphere,J.Geophys.Res., 103, 23,287 - 23,298, 1998.

Redemann, J., R. Turco, Liou, Russell, Bergstrom, Schmid, Livingston, Hobbs, Hartley, Ismail, Ferrare, Browell,Retrieving the Vertical Structure of the Aerosol Complex Index of Refraction From Aerosol In Situ and RemoteSensing Measurements During TARFOX, J. Geophys. Res., (2nd Special Issue on TARFOX), submitted 1999a.

Redemann, J., R. Turco, Liou, Russell, Bergstrom, Hobbs, Browell, Case Studies of the Vertical Structure of the DirectAerosol Radiative Forcing During TARFOX, J. Geophys. Res., (2nd Special Issue on TARFOX), submitted 1999b.

Redemann, J., P. Russell, and P. Hamill, Measurements and modeling of aerosol absorption and single scattering albedoat ambient relative humidity, Fall Meeting, Amer. Geophys. Union, submitted, 1999c.

Reid, J. S., and P. V. Hobbs, Physical and optical properties of young smokes from individual biomass fires in Brazil, J.Geophys. Res., 103, 32,013-32,030, 1998a.

Reid, J. S., P. V. Hobbs, R. J. Ferek, D. R. Blake, J. V. Martins, M. R. Dunlap, and C. Liousse, Physical, chemical, andoptical properties of regional hazes dominated by smoke in Brazil, J. Geophys. Res., 103, 32,059-32,080, 1998b.

Reid, J. S., P. V. Hobbs, C. Liousse, J. V. Martins, R. E. Weiss, and T. F. Eck, Comparisons of techniques for measuringshortwave absorption and black carbon content of aerosols from biomass burning in Brazil, J. Geophys. Res., 103,32,031-32,040, 1998c.

Remer, L. A., Gass�, S., Hegg, D. A., Kaufman, Y. J. and Holben, B. N. 1997. Urban/industrial aerosol: Ground-basedSun/sky radiometer and airborne in situ measurements, J. Geophys. Res. 102, 16,849-16,859.

Remer, L. A., and Y. Kaufman, Dynamic aerosol model: Urban/industrial aerosol, J. Geophys. Res., 103, 13,859-13,871,1998a.

Remer, L. A., Y. Kaufman, and B. Holben, The size distribution of ambient aerosol particles: Smoke vs. urban/industrialaerosol. Global Biomass Burning, J. S. Levine, Ed., MIT Press, Cambridge, MA 519-530, 1996.

Remer, L. A., Y. Kaufman, B. Holben, A. M. Thompson, and D. McNamara, A model of tropical biomass burningsmoke aerosol size distribution, J. Geophys. Res., 103, 31,879-31,892, 1998b.

Russell, P. B., Airborne sunphotometry and integrated analyses of smoke and haze aerosols, thin clouds, water vapor,and ozone in SAFARI 2000, A Proposed Investigation Presented at NASA EOS SAFARI 2000 Workshop, Boulder,CO, 12-14 May, 1999. Cost estimate and schedule submitted to NASA EOS Program Science Office and NASARadiation Science Program Office, February 1999; available from the author, NASA Ames Research Center, MoffettField, CA 94035-1000.

Russell, P. B., et al., Measurements with an airborne, autotracking, external-head sunphotometer, Preprint Volume, SixthConference on Atmospheric Radiation, May 13-16, 1986, pp. 55-58, Amer. Meteor. Soc., Boston, MA, 1986.

Russell, P.B. et al., Pinatubo and pre-Pinatubo optical depth spectra: Mauna Loa measurements, comparisons, inferredparticle size distributions, radiative effects, and relationship to lidar data. J. Geophys. Res, 98, 22, 969-22,985,1993a.

Russell, P. B. , and J. Heintzenberg, An overview of the ACE 2 Clear Sky Column Closure Experiment(CLEARCOLUMN), Tellus, accepted, 1999.

Russell, P. B., P. V. Hobbs, and L. L. Stowe, Aerosol properties and radiative effects in the United States east coast hazeplume: An overview of the Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX), J.Geophys. Res., 104, 2213-2222, 1999a.

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Russell, P. B., J. M. Livingston, P. Hignett, S. Kinne, J. Wong, and P. V. Hobbs, Aerosol-induced radiative flux changesoff the United States Mid-Atlantic coast: Comparison of values calculated from sunphotometer and in situ data withthose measured by airborne pyranometer, J. Geophys. Res., 104, 2289-2307, 1999b.

Russell, P.B., J.M. Livingston, R.F. Pueschel, J.A. Reagan, E.V. Browell, G.C. Toon, P.A. Newman, M.R. Schoeberl,L.R. Lait, L. Pfister, Q. Gao, and B.M. Herman, Post-Pinatubo optical depth spectra vs. latitude and vortex structure:Airborne tracking sunphotometer measurements in AASE II. Geophys Res. Lett, 20, 2571-2574, 1993b.

Russell, P. B., J. M. Livingston, R. F. Pueschel, J. B. Pollack, S. L. Brooks, P. J. Hamill, J. J. Hughes, L. W. Thomason,L. L. Stowe, T. Deshler, E. G. Dutton, and R. W. Bergstrom. Global to microscale evolution of the Pinatubovolcanic aerosol, derived from diverse measurements and analyses. J. Geophys. Res., 101, 18,745-18,763, 1996.

Russell, P. B., M. P. McCormick, and the SAGE III Aerosol ATBD Team, SAGE III Algorithm Theoretical BasisDocument (ATBD): Aerosol Data Products, Version 1.0, NASA Langley Research Center, Hampton, VA,(http://eospso.gsfc.nasa.gov/atbd/sagetables.html) November 15, 1996c.

Schmid B., K. J. Thome, P. Demoulin, R. Peter, C. Mätzler, and J. Sekler. "Comparison of Modeled and EmpiricalApproaches for Retrieving Columnar Water Vapor from Solar Transmittance Measurements in the 0.94 MicronRegion". Journal of Geophysical Research , 101, 9345-9358, 1996.

Schmid, B., J. J. Michalsky, R. N. Halthore, M. C. Beauharnois, L. C. Harrison, J. M. Livingston, and P. B. Russell,Comparison of aerosol optical depth from four solar radiometers during the Fall 1997 ARM Intensive ObservationPeriod, Geophys. Res. Lett., 27, 2725-2728, 1999a.

Schmid, B., Livingston, J. M., Russell, P. B., Durkee, P. A., Collins, D. R., Flagan, R. C., Seinfeld, J. H., Gasso, S.,Hegg, D. A., Ostrom, E., Noone, K. J., Welton, E. J., Voss, K., Gordon, H. R., Formenti, P., and Andreae, M. O..Clear sky closure studies of lower tropospheric aerosol and water vapor during ACE 2 using airborne sunphotometer,airborne in-situ, space-borne, and ground-based measurements. Tellus accepted, 1999b.

Scholes, R.J., D.E. Ward and C.O. Justice: Emissions of trace gases and aerosol particles due to vegetation burning insouthern hemisphere Africa. J. Geophys. Res., 101, 23,677-23,682, 1996.

Sokolik I.N., and O.B. Toon, Incorporation of mineralogical composition into models of the radiative properties ofmineral aerosol from UV to IR wavelengths. J. Geophys. Res., 104, 9423-9444, 1999.

Sokolik I.N., Nuts and bolts of radiative forcing by mineral dust. IGACtivities Newsletter, Issue 17, 12-14, May 1999.Spanner, M.A., R.C. Wrigley, R.F. Pueschel, J.M. Livingston and D.S. Colburn, Determination of atmospheric optical

properties during the first international satellite land surface climatology project field experiment. J. Spacecraft andRockets, 27, 373-379, 1990.

Steele, H. M., and R. P. Turco, The measurement and prediction of aerosol extinction: implications for SAGE II ozoneconcentrations and trends, J. Geophys. Res., in press, 1997.

Swap, R. J., and H. J. Annegarn, Southern African Regional Science Initiative: SAFARI 2000: Science Plan (Draftavailable at http://safari.gecp.virginia.edu/schedule/ftptoc.html), 1999.

Swap, R., H. Annegarn, M. Scholes, and C. Justice, SAFARI-2000: A Southern African Regional Science Initiative,IGACtivities Newsletter 15, IGAC Core Project Office, Cambridge, MA, 1998a.

Swap, R., J. Privette, M. King, D. Starr, T. Suttles, H. Annegarn, M. Scholes, and C. Justice, SAFARI 2000: A SouthernAfrican Fire/Atmosphere Regional Science Initiative, Earth Observer 10, No. 6, 31-34, EOS Project Science Office,NASA Goddard Space Flight Center, Greenbelt, MD, 1998b.

Tanre, D., L. A. Remer, Y. J. Kaufman, S. Mattoo, P. V. Hobbs, J. M. Livingston, P. B. Russell, and A. Smirnov,Retrieval of aerosol optical thickness and size distribution over ocean from the MODIS airborne simulator duringTARFOX, J. Geophys. Res., 104, 2261-2278, 1999.

Thomason L. W., 1985: Extinction of near infrared solar radiation as a means for remote determination of atmosphericwater vapor. Ph. D. dissertation, University of Arizona Tucson. pp.Ê122.

Toon, O., E. Browell, B. Gary, L. Lait, J. Livingston, P. Newman, R. Pueschel, P. Russell, M. Schoeberl, G. Toon, W.Traub, F.P.J. Valero, H. Selkirk, J. Jordan, Heterogeneous reaction probabilities, solubilities, and the physical state ofcold volcanic aerosols, Science, 261, 1136-1140, 1993.

Veefkind, J. P., G. de Leeuw, P. A. Durkee, P. B. Russell, P. V. Hobbs, and J. M. Livingston, Aerosol optical depthretrieval using ATSR-2 and AVHRR data during TARFOX, J. Geophys. Res., 104, 2253-2260, 1999.

Vermote, E. F., et al., Atmospheric correction of visible to middle-infrared EOS-MODIS data over land surfaces:Background, operational algorithm and validation, J. Geophys. Res., 102, 17,131-17,142, 1997.

Wanner, W., et al., Global retrieval of bidirectional reflectance and albedo over land from EOS MODIS and MISR data:Theory and algorithm, J. Geophys. Res., 102, 17,143-17,162, 1997.

Ward, D. E., and C. C. Hardy, Smoke emissions from wildland fires, Environ. Int., 17, 117-134, 1991.Ward, D. E., and L. F. Radke, Emission measurements from vegetation fires: A comparative evaluation of methods and

results, in Fire in the Environment: The Ecological, Atmospheric and Climatic Importance of Vegetation Firesedited by P. J. Crutzen and J. G. Goldammer, John Wiley, Chichester, England, 1993.

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Welton, E.J., K.J. Voss, H.R. Gordon, H. Maring, A. Smirnov, B. Holben, B. Schmid, J.M. Livingston, P.B. Russell,P.A. Durkee, P. Formenti, M.O. Andrea, and O. Dobovik, Ground-based lidar measurements of aerosols during ACE2: Instrument description, results, and comparisons with other ground based and airborne measurements, Tellus,accepted, 1999.

Wrigley, R.C., M.A. Spanner, R.E.. Sly, R.F. Pueschel, and H.R. Aggarwal, Atmospheric correction of remotely sensedimage data by a simplified model. J. Geophys. Res., 97, 18797-18814, 1992.

Yamasoe, M. A., Y. J. Kaufman, O. Dubovik, L. A. Remer, B. N. Holben, and P. Artaxo, Retrieval of the real part of therefractive index of smoke particles from Sun/sky measurements during SCAR-B, J. Geophys. Res., 103, 31,893-31,902, 1998.

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6 BUDGET

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7 STAFFING, RESPONSIBILITIES, AND VITAE

Dr. Philip B. Russell will be Principal Investigator. As such, he will supervise the work, lead the planning,and participate in the modeling and analyses, as well as selected presentations and publications. He will beresponsible for the completion of the work within budget and schedule. John Livingston and Drs. BeatSchmid, Jens Redemann, and Robert Bergstrom will participate in the development and use of algorithms andmodels and will lead and/or participate in specified data analyses, presentations, and publications.Specifically, Drs. Russell and Redemann will co-lead Tasks 1.1 and 2.2, Dr. Schmid will lead Tasks 1.2, 1.3,and 2.4, Mr. Livingston will lead Tasks 1.4 and 1.5, Drs. Bergstrom and Redemann will co-lead Tasks 1.6and 2.5, and Dr. Russell will lead Tasks 2.1, 2.3, and 2.6.

Prof. Kenneth Voss, who coauthored the Algorithm Theoretical Basis Document for the MODIS NormalizedWater-leaving Radiance (atmospheric correction) data product will provide a link to the MODIS Ocean dataproduct algorithms, access to quick-look MODIS ocean data products, and advice and oversight on the use ofthe airborne sunphotometers in validating MODIS ocean algorithms and furnishing complementary data toMODIS ocean investigations. Dr. Didier Tanre, a member of the MODIS Atmosphere Science Team, willprovide a link to that team and will provide advice and oversight on the use of the airborne sunphotometers invalidating MODIS and MODIS Airborne Simulator (MAS) aerosol products and furnishing complementarydata to MODIS atmospheric investigations. Dr. TanreÕs institution, USTL, has endorsed his participation inNASA research projects, including development of MODIS algorithms and use of MODIS and MODISAirborne Simulator data in integrated satellite/aircraft/ground field experiments. He makes frequent trips tothe US for this purpose, and he will be available to interact with other team members and attend programreviews on these trips. Dr. Jay Herman, the PI for Meteor-3M/TOMS and for TOMS Aerosol/UV projects,will provide access to quick-look TOMS aerosol and ozone products, as well as advice and oversight on theuse of the airborne sunphotometers in validating TOMS aerosol and ozone products and furnishingcomplementary data to TOMS atmospheric investigations.

(a) Philip B. RussellVita

B.A., Physics, Wesleyan University (1965, Magna cum Laude; Highest Honors). M.S. and Ph.D., Physics, StanfordUniversity (1967 and 1971, Atomic Energy Commission Fellow). M.S., Management, Stanford University (1990,NASA Sloan Fellow).

Postdoctoral Appointee, National Center for Atmospheric Research (1971-72, at University of Chicago and NCAR).Physicist to Senior Physicist, Atmospheric Science Center, SRI International (1972-82). Chief, AtmosphericExperiments Branch (1982-89), Acting Chief and Acting Deputy Chief, Earth System Science Division (1988-89),Chief, Atmospheric Chemistry and Dynamics Branch (1989-95), Research Scientist (1995-present), NASA AmesResearch Center.

Currently, Co-coordinator for the CLEARCOLUMN component of the Second Aerosol Characterization Experiment(ACE 2) of the International Global Atmospheric Chemistry (IGAC) Project. Member, Science Team for Global AerosolClimatology Project (GACP; Investigation Title: Improved Exploitation of Field Data Sets to Address AerosolRadiative-Climatic Effects and Development of a Global Aerosol Climatology). Member, Science Teams for SAGE IIand SAGE III (satellite sensors of stratospheric aerosols, ozone, nitrogen dioxide, and water vapor). Primaryresponsibilities: analyses of volcanic aerosol properties and effects, development of the SAGE III Aerosol AlgorithmTheoretical Basis Document (ATBD), and experiment design and data analyses to validate the satellite measurements.

Previously, NASA Ames Associate Fellow (1995-96, awarded for excellence in atmospheric research).

Previously, Coordinator for IGACÕs Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX).Convenor of TARFOX Special Sessions, Spring 1997 Meeting, American Geophysical Union (AGU). Coordinator,TARFOX special issues of Journal of Geophysical Research (1998-99). Program Co-Chair, International SpecialtyConference on Visual Air Quality, Aerosols, and the Global Radiation Balance (Bartlett, New Hampshire, 10/1997).Member, Direct Aerosol Radiative Forcing Committee of IGAC Focus 8: Atmospheric Aerosols (1996-98).

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Previously, Editor (1993, 1996) and Editor-in-Chief (1994-95), Geophysical Research Letters; Member, Board ofEditors and Atmospheric Science Executive Committee, American Geophysical Union. Guest Editor, Journal ofGeophysical Research Special Issues on "Midlatitude Stratospheric Dynamics and Cross-Tropopause Exchange,""Tropical Stratosphere-Troposphere Exchange," and "SAGE II Aerosol and Ozone Data Validation and Initial Data Use"(1988-93). Convenor, Sessions on the Atmospheric Effects of 1991 Pinatubo Eruption, AGU Fall Meeting (1992).Organizer and/or report editor, Workshops on "Requirements for a Very-High-Altitude Aircraft for AtmosphericResearch," "Scientific Application of Remotely Piloted Aircraft Measurements of Radiation, Water Vapor, and TraceGases to Climate Studies," and "Mission Measurement Strategies for the Subsonic Assessment Program" (1989-94).Member, Interagency Task Group on Airborne Geoscience (1987-89), Member, American Institute of Aeronautics andAstronautics (AIAA) Losey Atmospheric Sciences Award Selection Committee, (1986-87), Member, AIAAAtmospheric Environment Technical Committee (1984-90), Invited Participant, World Meteorological OrganizationExperts Meeting on Aerosols and their Climatic Effects (1983), Invited Participant, NOAA Workshop on Global LargeAerosols (1982), Chair, American Meteorological Society International Committee on Laser Atmospheric Studies(1979-82, Member, 1978-82), Member, National Research Council Committee on Army Basic Research (1979-81),Member, American Meteorological Society Committee on Radiation Energy (1979-81).

Previously, Project Scientist, Small High-Altitude Science Aircraft (SHASA) Project to develop the Perseus A RemotelyPiloted Aircraft (RPA, 1992-94), Member, Science/Aeronautics Seam Team of NASA Ames Reorganization Team(1994), Member, Ad Hoc Committee on the NASA Environmental Research Aircraft and Sensor Technology (ERAST)Program (1993-4), Member, NASA Red Team on Remote Sensing and Environmental Monitoring of Planet Earth(1992-3), Leader, NASA Ames Earth Science Advanced Aircraft (ESAA) Team (1990-94), Member, National Aero-Space Plane (NASP) Committee on Natural Environment (1988-94), Member, NASA Ames Strategy and TacticsCommittee (1986-87), Chair, NASA Ames Atmospheric Science Strategy Review Team (1986-87), Manager, NASAStratosphere-Troposphere Exchange Project (STEP, 1983-93), Member, NASA Solar-Terrestrial Observatory ScienceStudy Group (1979-80), Member, NASA Atmospheric Lidar Working Group (1977-79) , Member, NASA Spacelab 2Investigations Review Panel (1977).

NASA Exceptional Service Medal (1988, for managing Stratosphere-Troposphere Exchange Project), NASA Space ActAward (1989, for invention of Airborne Autotracking Sunphotometer), and NASA Group Achievement Awards (1994,for Stratospheric Photochemistry, Aerosols and Dynamics Expedition; 1991, for Airborne Arctic StratosphericExpedition; and 1989, for Airborne Antarctic Ozone Experiment). Graham Prize (1965, outstanding undergraduate innatural science, Wesleyan University). Member, Phi Beta Kappa and Sigma Xi.

Patent, "Airborne Tracking Sunphotometer Apparatus and System" ( U.S. Pat. No. 4,710,618, awarded 1987)

PUBLICATIONS(Selected from 81 peer-reviewed publications)

Russell, P. B., and J. Heintzenberg, An overview of the ACE 2 Clear Sky Column Closure Experiment(CLEARCOLUMN), Tellus, accepted, 1999.

Bergstrom, R. W., and P. B. Russell, Estimation of aerosol radiative effects over the mid-latitude North Atlantic regionfrom satellite and in situ measurements. Geophys. Res. Lett., 26, 1731-1734, 1999.

Russell, P. B., P. V. Hobbs, and L. L. Stowe, Aerosol properties and radiative effects in the United States Mid-Atlantichaze plume: An overview of the Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX), J.Geophys. Res., 104, 2213-2222, 1999a.

Russell, P. B., J. M. Livingston, P. Hignett, S. Kinne, J. Wong, and P. V. Hobbs, Aerosol-induced radiative flux changesoff the United States Mid-Atlantic coast: Comparison of values calculated from sunphotometer and in situ data withthose measured by airborne pyranometer, J. Geophys. Res., 104, 2289-2307, 1999b.

Russell, P. B., S. Kinne and R. Bergstrom, "Aerosol Climate Effects: Local Radiative Forcing and Column ClosureExperiments," J. Geophys. Res., 102, 9397-9407, 1997.

Russell, P. B., J. M. Livingston, R. F. Pueschel, J. J. Bauman, J. B. Pollack, S. L. Brooks, P. Hamill, L. W. Thomason, L.L. Stowe, T. Deshler, E. G. Dutton, and R. W. Bergstrom. "Global to Microscale Evolution of the Pinatubo VolcanicAerosol, Derived from Diverse Measurements and Analyses." J. Geophys. Res., 101, 18,745-18,763, 1996a.

Russell, P.B., L. Pfister, and H.B. Selkirk. "The Tropical Experiment of the Stratosphere-Troposphere Exchange Project(STEP): Science Objectives, Operations, and Summary Findings." J. Geophys. Res., 98, 8563-8589, 1993.

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Russell, P.B., J. M. Livingston, R. F. Pueschel, J. A. Reagan, E.V. Browell, G. C. Toon, P.A. Newman, M.R. Schoeberl,L.R. Lait, L. Pfister, Q. Gao, and B. M. Herman. "Post-Pinatubo Optical Depth Spectra vs. Latitude and VortexStructure: Airborne Tracking Sunphotometer Measurements in AASE II." Geophys. Res. Lett., 20, 2571-2574, 1993.

Russell, P.B., and M.P. McCormick. "SAGE II Aerosol Data Validation and Initial Data Use: An Introduction andOverview." J. Geophys. Res., 94, 8335-8338, 1989.

Russell, P.B., M.P. McCormick, T.J. Swissler, J.M. Rosen, D.J. Hofmann, and L.R. McMaster. "Satellite andCorrelative Measurements of the Stratospheric Aerosol: III. Comparison of Measurements by SAM II, SAGE,Dustsondes, Filters, Impactors, and Lidar." J. Atmos. Sci., 41, 1791-1800, 1984.

Russell, P.B., T.J. Swissler, M.P. McCormick, W.P. Chu, J.M. Livingston, and T.J. Pepin. "Satellite and CorrelativeMeasurements of the Stratospheric Aerosol: I. An Optical Model for Data Conversions." J. Atmos. Sci., 38, 1270-1294, 1981.

Russell, P.B., J.M. Livingston, and E.E. Uthe. "Aerosol-Induced Albedo Change: Measurement and Modeling of anIncident." J. Atmos. Sci., 36, 1587-1608, 1979.

(b) Beat SchmidVita

Senior Research Scientist, Bay Area Environmental Research InstituteMS-245, NASA Ames Research Center, Moffett Field, CA 94035-1000

Phone: 650 604 5933 Fax: 650 604 3625, E-Mail: bschmid@mail.arc.nasa.gov

Relevant Education

¥Diploma, Physics (1991, Institute of Applied Physics, University of Bern, Switzerland. Thesis: "Monitoring VegetationDevelopment in Switzerland by Means of NOAA/AVHRR-Satellite Data")

¥Ph. D., Physics (1995, Institute of Applied Physics, University of Bern, Switzerland. Thesis: "Sun Photometry, a Toolfor Monitoring Atmospheric Parameters")

¥June 1995-April 1997: Research assistant, University of Bern, Institute of Applied Physics.

¥Oct. 1995 -Jan. 1996: Visiting scientist at University of Arizona, Optical Sciences Center, Tucson, AZ.

¥May 1997-Present: Senior Research Scientist, Bay Area Environmental Research Institute / NASA Ames ResearchCenter, Moffett Field, CA.

Qualifications Summary

¥ Expert in the field of ground-based and airborne sunphotometry

¥ Extensive experience in radiometric calibration

¥ Strong background in the measurement and the theory of atmospheric aerosol, gases and radiation

¥ Experience in Earth and atmospheric remote sensing from UV to micro-wave

¥ Excellent communication and public speaking skillsPublications

Schmid B., C. M�tzler C., and E. Schanda, 1991: Temporal Evolution of Vegetation Indices and Atmospheric Effects,Proceedings of the 11th EARSeL-Symposium, 3-5 July 1991, Graz, Austria, pp. 355-368.

Peter R., and B. Schmid, 1993, Comparison of Columnar Water Vapor Determined from Microwave Emission and SolarTransmission Measurements. Proceedings of Topical Symposium on Combined Optical-Microwave Earth andAtmosphere Sensing, March 22-25, Albuquerque, NM, pp. 193-197.

Schmid B., R. Peter R., and C. M�tzler, 1993: Intercomparisons of Columnar Water Vapor Retrievals Obtained with aSun photometer and a Microwave Radiometer, PIERS'93, July 12-16, Pasadena, CA.

Schmid B., and C. Wehrli, 1994: High Precision Calibration of a Sun Photometer Using Langley Plots Performed atJungfraujoch (3580 m) and Standard Irradiance Lamps. Proceedings of IGARSSÕ94, August 8-12, Pasadena, CA, pp.2Õ314-2Õ316.

Schmid B., and C. Wehrli, 1995: Comparison of Sun Photometer Calibration by Langley Technique and Standard Lamp.Applied Optics, Vol. 34, No. 21, 4500-4512.

Schmid B., K. J. Thome, P. Demoulin, R. Peter, C. M�tzler, and J. Sekler, 1996: Comparison of Modeled and EmpiricalApproaches for Retrieving Columnar Water Vapor from Solar Transmittance Measurements in the 0.94 MicronRegion. Journal of Geophysical Research, Vol. 101, No. D5, 9345-9358.

Demoulin P., B. Schmid, G. Roland and C. Servais, 1996: Vertical Column Abundance and Profile Retrievals of WaterVapor Above the Jungfraujoch. Atmospheric Spectroscopic Aplications Workshop, Reims, France, September 1996,pp. 131-134.

Schmid B., C. M�tzler, A. Heimo, and N. K�mpfer, 1997: Retrieval of Optical Depth and Size Distribution ofTropospheric and Stratospheric Aerosols by Means of Sun Photometry. IEEE Transactions on Geoscience andRemote Sensing, Vol 35, No.Ê1, 172-182.

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Schmid B., J.M. Livingston, P.B. Russell, and P.A. Durkee, 1997: "Three Dimensional Measurements of LowerTropospheric Aerosol Optical Depth Spectra and Water Vapor Amounts during ACE 2 by Means of AirborneSunphotometry." EOS Trans. Amer Geophys. Union, 78, F97, 1997.

Livingston J.M., V. Kapustin, B. Schmid, P.B. Russell, P.A. Durkee, T.S. Bates, and P.K. Quinn, 1997: "ShipboardSunphotometer Measurements of Aerosol Optical Depth Spectra During ACE 2." EOS Trans. Amer Geophys. Union,78, F97-98.

Schmid B., P.R. Spyak, S.F. Biggar, Ch. Wehrli, J. Sekler, T. Ingold, C. M�tzler, and N. K�mpfer, 1998: ÒEvaluation ofthe applicability of solar and lamp radiometric calibrations of a precision Sun photometer operating between 300 and1025 nm.Ó Appl. Opt., Vol 37, No. 18, 3923-3941.

(c) Jens RedemannVita

Research Scientist, Bay Area Environmental Research InstituteMS-245, NASA Ames Research Center, Moffett Field, CA 94035-1000

Phone: (650) 604-6259 Fax: (650) 604-3625, email: jredemann@mail.arc.nasa.gov

PROFESSIONAL EXPERIENCE

Research Scientist April 1999 to present

Bay Area Environmental Research Institute, San Francisco.

Research Assistant May 1995 to March 1999

University of California, Los Angeles, Department of Atmospheric Sciences.

Lecturer Jan. 1999 to March 1999

University of California, Los Angeles, Department of Atmospheric Sciences.

Tutor 1997 to 1998

Ivy West Educational Services, Marina Del Rey, CA.

Research Assistant June 1994 to April 1995

Free University of Berlin, Germany. Department of Physics.

Consultant July 1989 to August 1993

Zander Cleanroom Technology, Nuremberg, Germany.

EDUCATION

Ph.D. in Atmospheric Sciences. 1999

University of California, Los Angeles. Specialization: atmospheric physics and chemistry.

M.S. in Atmospheric Sciences. 1997

University of California, Los Angeles. Specialization: atmospheric physics and chemistry.

M.S. in Physics. 1995

Free University of Berlin, Germany. Specialization in experimental physics and mathematics.

RELEVANT RESEARCH EXPERIENCE

• Developed inversion algorithms (C and IDL) and data analysis tools for aircraft-based lidar andsunphotometer measurements during field experiments (PEM, TARFOX).

• Compared remotely sensed data to aerosol in situ measurements and devised techniques to retrieve thevertical structure of aerosol optical properties and radiative effects.

• Involved in the development of a multi-wavelength, ground-based lidar system at the Free University ofBerlin, Germany.

• Provided solutions to scientific and numerical problems pertaining to aerosol physics and performedvalidation measurements relevant to Clean Room Technology for the computer chip industry.

• Specialized course work in atmospheric sciences, geophysical fluid dynamics, cloud physics, radiativetransfer and remote sensing.

HONORS

Invited Speaker at the Atmospheric Chemistry Colloquium for Emerging Senior Scientists(ACCESS V).

June 1999

Outstanding Student Paper Award, American Geophysical Union - fall meeting. 1998

NASA Global Change Research Fellowship Awards. 1996-1998

UCLA Neiburger Award for excellence in the teaching of the atmospheric sciences. 1997

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ORGANIZATIONS

American Association for Aerosol Research, American Geophysical Union, Co-president of the UCLA - AtmosphericSciences Graduate Student Group.

SELECTED PUBLICATIONS

Redemann, J., R.P. Turco, K.N. Liou, P.B. Russell, R.F. Pueschel, E.V. Browell. Evidence of Positive Aerosol RadiativeForcing Events in the Pacific Basin Troposphere, 1999 (in preparation for GRL).

Redemann, J., R.P. Turco, K.N. Liou, P.B. Russell, R.W. Bergstrom, B. Schmid, J.M. Livingston, P.V. Hobbs, S. Ismail,E.V. Browell. Retrieving the Vertical Structure of the Aerosol Complex Index of Refraction From Aerosol InSitu and Remote Sensing Methods During TARFOX, 1999 (submitted, 2nd TARFOX JGR special issue).

Redemann, J., R.P. Turco, K.N. Liou, P.B. Russell, R.W.Bergstrom, P.V. Hobbs, E.V. Browell. Case Studies of theVertical Structure of the Aerosol Radiative Forcing During TARFOX, 1999 (submitted, 2nd TARFOX JGRspecial issue).

Redemann, J., R.P. Turco, R.F. Pueschel, M.A. Fenn, E.V. Browell and W.B. Grant. AÊMulti-Instrument Approach forCharacterizing the Vertical Structure of Aerosol Properties: Case Studies in the Pacific Basin Troposphere, J.Geophys. Res., 103, 23,287 - 23,298, 1998. (peer-reviewed)

Redemann, J., R.P. Turco, R.F. Pueschel, E.V. Browell, W.B. Grant. Combining Data From Lidar and In SituInstruments to Characterize the Vertical Structure of Aerosol Optical Properties, Presented at the NineteenthInternational Laser Radar Conference, Annapolis, MD, July 6-10, 1998, NASA/CP-1998-207671/PT1, pp.95-99, 1998.

Redemann, J., R.P. Turco, R.F. Pueschel, E.V. Browell, W.B. Grant. Comparison of Aerosol Measurements by Lidarand In Situ Methods in the Pacific Basin Troposphere, in ÔAdvances in Atmospheric Remote Sensing withLidarÕ, A.ÊAnsmann, R.Neuber, P.Rairoux, U.Wandinger (eds.), pp.55-58, Springer, Berlin, 1996. (peer-reviewed)

Pueschel, R.F.; D.A. Allen, C. Black, S. Faisant, G.V. Ferry, S.D. Howard, J.M.ÊLivingston, J. Redemann, C.E.Sorensen, S. Verma, Condensed Water in Tropical Cyclone ÒOliverÓ, 8 February 1993, Atmospheric Research,38, pp.297-313, 1995. (peer-reviewed)

(d) John LivingstonVita

Senior Research Meteorologist, Geoscience and Engineering Center, Advanced Development DivisionSRI International, Menlo Park, CA 94025

Specialized Professional CompetenceAtmospheric physics and meteorology; atmospheric radiometry; computer simulation of atmospheric remote sensing

systems; numerical analysis and inversion of in-situ and remotely sensed atmospheric data

Representative Research Assignments at SRI (Since 1978)Acquisition and analysis of spectral solar radiance measurements

Validation of satellite particulate extinction measurements (SAM II, SAGE I, and SAGE II), and corresponding

studies of the global distribution of stratospheric aerosols

Inversion of spectral extinction measurements to derive aerosol size-distribution parameters

Analysis of in situ measurements of stratospheric and tropospheric aerosols

Modeling and analysis of Differential Absorption Lidar measurements of tropospheric ozone

Simulation of passive sensor radiance measurements to infer range to an absorbing gas

Experimental study of aerosol effects on solar radiation using remote sensors

Error analysis and simulation of lidar aerosol measurements

Analysis of lidar propagation through fog, military smoke, and dust clouds

Evaluation of the lidar opacity method for enforcement of stationary source emission standards

Weather forecasting for large-scale air pollution field study

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Testing and evaluation of an offshore coastal dispersion computer model

Application of objective wind field and trajectory models to meteorological measurements

Other Professional ExperienceResearch assistant, University of Arizona Institute of Atmospheric Physics (1974-1977)

NASA Kennedy Space Center (1975-1976): participant in thunderstorm electrification studies

Academic BackgroundB.S. summa cum laude in geology (1974), University of Notre Dame

M.S. in atmospheric sciences (1977), University of Arizona

M.B.A. with highest honors (1992), Santa Clara University

University of Notre Dame Year-in-Japan Program (1971-1972), Sophia University, Tokyo

Professional Associations and HonorsAmerican Meteorological Society; American Geophysical Union

PublicationsAuthor or co-author of more than two dozen articles in refereed scientific journals, in addition to numerous

contributions in conference proceedings, and SRI reports

(e) Robert W. BergstromVita

B.S., Mechanical Engineering, Oregon State University (1968). M.S. and Ph.D., Mechanical Engineering, PurdueUniversity (1969 and 1972). J.D., Law, Stanford University (1983). Member of the California Bar (1983-present).

Post-Doctoral Fellow, Mainz University, Germany (1972-1973). National Research Associate, NASA Ames ResearchCenter (1974-1977) . Senior Scientist, Systems Application Inc., San Rafael CA (1997 Ð 1980). Associate, Law Firm ofMcCutchen, Doyle, Brown and Enersen, San Francisco (1983-1984). Assistant Regional Counsel, U.S. EPA, Region IX,San Francisco, (1984-1992).

Founder of the Bay Area Environmental Research Institute, San Francisco, CA (1992). Currently, Director of Research.Guest Investigator on the UARS Satellite Science Team using the satellite data to explore the effects of the Pinatuboaerosol on atmospheric radiation. Principal Investigator on several Cooperative Agreements with NASA Ames ResearchCenter. Currently investigating the effects of aerosols on atmospheric radiation during ACE 2.

Selected Publications

Bergstrom, R.W. and P.B. Russell, Estimation of aerosol radiative effects over the mid-latitude North Atlantic regionfrom satellite and in situ measurements, Geophys. Res. Lett., 26, 1731-1734, (1999).

Sokolik, I., O.B. Toon and R.W. Bergstrom, ÒModeling the Radiative Characteristics ofAirborne Mineral Aerosols at Infrared Wavelengths,Ó J. Geophys. Res., 103, 8813-8826, (1998).

Pilewskie, P. et al. (including R.W. Bergstrom), Observations of the spectral distribution of solar irradiance at theground During SUCCESS,Ó Geophys. Res. Lett., 25, 1141-1144, 1998.

Russell, P.B. S. Kinne and R.W. Bergstrom: ÒAerosol climate effects: Local radiative forcing and column closureexperiments,Ó J. Geophys.Res, 102, 9397, (1997)

Kinne, S. et al (including R.W. Bergstrom), "Cirrus Cloud Radiative and Microphysical Properties from GroundObservations during FIRE Ô91," J. Atmos. Sci., 54, 2320 (1997).

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Seiegnuer, C., et al (including R.W. Bergstrom), ÒFormulation of a Second-Generation Reactive Plume and VisibilityModel,Ó J. Air & Waste Man. Assoc., 47, 176 (1997)

Russell, P.B. et al (including R.W. Bergstrom), ÒGlobal to microscale evolution of the Pinatubo volcanic aerosol derivedfrom diverse measurement and analyses,Ó J. Geophys. Res., 101, 18,745 (1996)

Wu, X.H., S. Seignuer and R. W. Bergstrom ÒEvaluation of a sectional representation of aerosol size distributions forcalculations of optical properties,Ó J. Geophys. Res. 101, 19277, (1996)

Bergstrom, R.W., B.L. Babson and T.P. Ackerman, "Calculation of Multiply Scattered Radiation in CleanAtmospheres," Atmos. Environ., 15, 1821 (1981).

Bergstrom, R.W. and A.C. Cogley, "Scattering of Emitted Radiation from Inhomogeneous and Nonisothermal Layers,"J. Quant. Spect. Rad. Trans., 21, 279 (1979).

Cogley A.C. and R.W. Bergstrom, "Numerical Results for the Thermal Scattering Functions," J. Quant. Spect. Rad.Trans., 21, 263 (1979).

Bergstrom R.W. and J.T. Peterson, 'Comparison of Observed and Predicted Solar Radiation in an Urban Area," J. App.Met., 16, 1107 (1977).

Bergstrom, R.W. "Extinction and Absorption Coefficients of Atmospheric Aerosols as a Function of Particle Size,"Beitr�ge zur Physik der Atmosph�re, 46, 223 (1973).

Bergstrom, R.W. "Comments on the Estimation of the Absorption Coefficients of Atmospheric Aerosols," Beitr�ge zurPhysik der Atmosph�re, 46, 198 (1973).

Bergstrom, R.W. "Prediction of the Spectral Absorption and Extinction Coefficients of An Urban Air Pollution AerosolModel," Atmos. Environ., 6, 247 (1972).

(f) Kenneth J. VossVita

Professor, Department of PhysicsUniversity of Miami, Coral Gables Fl. 33124

Phone: (305) 284 2323 Fax: (305) 284 4222, email: voss@physics.miami.edu

B.S. Physics, Washington State University (1979), Ph. D., Physics, Texas A&M University, (1984).

Postgraduate Research Physicist (1984-1987, Visibility Laboratory, Scripps Institution of Oceanography, Univ. of Cal.San Diego). Assistant Research Optical Oceanographer, (1987-1989, Institute of Marine Resources, Scripps Institutionof Oceanography). Assistant Professor to Professor, University of Miami (1989-present).

Topical Editor for Applied Optics(1994 – present). Chairman, Atmospheric and Oceanic Optics Technical Group,Optical Society of America (1994-1995). Vice Chairman, Atmospheric and Oceanic Optics Technical Group, OpticalSociety of America (1993).

Recent Refereed journal articles (last 2 years):

C. Hu and K. J. Voss, “Measurement of solar stimulated fluorescence in natural waters”, 1998, Limnol. and Ocean., 43:1198 - 1206.

K J. Voss, W. M. Balch, K. A. Kilpatrick, Scattering and attenuation properties of Emiliania huxleyi cells and theirdetached coccoliths, 1998, Limnol. and Ocean., 43: 870-876.

K. D. Moore, K. J. Voss, and H. R. Gordon, “Spectral reflectance of Whitecaps: Instrumentation, calibration, andperformance in coastal waters”, 1998, J. Atm. and Ocean. Techn., 15: 496-509.

32 3:18 PM, 10/20/00

J. S. Bartlett, K. J. Voss, S. Sathyendranath, and A. Vodacek, “ Raman scattering by pure water and seawater”, 1998,Applied Optics, 37: 3324 - 3332.

Y. Liu and K. J. Voss, “Polarized radiance distribution measurements of skylight: II. experiment and data”, 1997,Applied Optics, 36: 8753 - 8764.

C. Hu and K. J. Voss, “In situ measurement of Raman scattering in clear ocean water”, 1997, Applied Optics, 36: 6962 -6967.

D. K. Clark, H. R. Gordon, K. J. Voss, Y. Ge, W. Broenkow, and C. Trees, “Validation of Atmospheric Correction overthe Oceans”, 1997, J. Geophys. Res., 102: 17,209-17,217.

K. J. Voss and Y. Liu, “Polarized radiance distribution measurements of skylight: I. system description andcharacterization.”, 1997, Applied Optics, 36 :6083-6094.

B. J. Frew and K. J. Voss, “Measurement of the Point Spread Function in a layered system”, 1997, Applied Optics, 36:3335-3337.

(g) Didier TanreVita

Education:M.Sc. in Physics in 1975 and Thèse de 3ème Cycle and Doctorat d'État in Atmospheric Physics in 1977and 1982, respectively; all from the Université des Sciences et Techniques de Lille, France.

Research and academic employment:Joined CNRS (Centre National de la Recherche Scientifique), collocated with the Laboratoire d'OptiqueAtmosphérique at the Université des Sciences et Techniques de Lille, Villeneuve d'Ascq, France, as aResearch Scientist in 1982.NRC Resident Research Associate at NASA Goddard Space Flight center from 1989 through 1991.

Research interestRemote sensing of aerosol from space,Experience in ground based-measurements (AERONET).Experience in radiative transfer theory (5S and 6S codes)

MembershipsMember of Earth Observing System - MODIS science team.Member of the POLDER Science Team on ADEOSMember of the GEWEX Radiation PanelChairman of the French Satellite Remote Sensing Program

Honors and AwardsTransactions Prize Paper Award (1993) from the IEEE Geoscience and Remote Sensing Society for bestpaper of the year in the IEEE Transactions on Geoscience and Remote Sensing.

Recent publications:

1997 :Bouffies S., Bréon F.M., Tanré D., Dubuisson P., Atmospheric Water Vapor Estimate by a Differential

absorption Technique with the POLDER Instrument, J. Geophys. Res., 102, 3831-3841, 1997.Cachorro V. E., Tanré D., The Correlation between Particle Mass Loading and Extinction: Application to

Desert Dust Aerosol Content Estimation, Rem. Sens. Environ., 60, 187-194, 1997.Liousse C., Dulac F., Cachier H., Tanré D., Remote Sensing of Carbonaceous Aerosol Production by African

Savanna Biomass Burning, J. Geophys. Res., 102, 5895-5911, 1997.

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Roujean J.L., Tanré D., Bréon F.M., Deuzé J.L., Retrieval of land surface parameters for GCM from POLDERbidirectional measurements during HAPEX-SAHEL, J. Geophys. Res., 102, 11201-11218, 1997.

Soufflet V., Tanré D., Royer A., O'neil N., Remote Sensing of aerosols over boreal forest and lake fromAVHRR/NOAA data, Rem. Sens. Environ., 60, 22-34, 1997.

Vermote E. F., Tanré D., Deuzé J.L, Herman M., Morcrette J.J., Second Simulation of the Satellite Signal in theSolar Spectrum: An Overview, IEEE Transactions on Geoscience and Remote Sensing, 35, 675-686, 1997.

1997: (JGR/Numéro Spécial: Passive remote sensing of tropospheric aerosols and atmospheric correctionsof the aerosol effect)

Bréon, F.M., J.L. Deuzé, D. Tanré, M. Herman, Validation of spaceborne estimates of aerosol loading fromsunphotometer measurements with emphasis on the polarization, J. Geophys. Res., 17187-17196, 1997.

Herman M., Deuzé J.L., Devaux C., Goloub P., Bréon F.M., Tanré D., Remote Sensing of Aerosols over LandSurfaces Including Polarization Measurements: Applications to POLDER Measurements, J. Geophys. Res.,17039-17050, 1997.

Kaufman Y.J., Tanré D., Gordon H.R., Nakajima T., Lenoble J., Frouin R., Grassl H., Herman B.M., King M.,Teillet P.M., Passive Remote Sensing of Tropospheric Aerosol and Atmospheric correction for the AerosolsEffects, J. Geophys. Res., 16815-16830, 1997.

Kaufman Y.J., Tanré D., Remer L., Vermote E., Holben B.N., Operational Remote Sensing of TroposphericAerosols over the Land from EOS-MODIS, J. Geophys. Res., 17051-17068, 1997.

Leroy, M., J.L. Deuzé, F.M. Bréon, O. Hautecoeur, M. Herman, J.C. Buriez, D. Tanré, S. Bouffiès, P. Chazette,And J.L. Roujean, Retrieval of Atmospheric Properties and Surface Bidirectional Reflectances Over theLand From POLDER/ADEOS, J. Geophys. Res., 17023-17038, 1997.

Tanré D, Kaufman Y.J., Herman M., Mattoo S., Remote sensing of aerosols properties over oceans using theMODIS/EOS spectral radiances, J. Geophys. Res., 16971-16988, 1997.

Vermote E., N. El. Saleous, C.O. Justice, Y.J. Kaufman, J.L. Privette, L. Remer, J.C. Roger, D. Tanré,Atmospheric corrections of visible to middle-infrared EOS-MODIS data over land surfaces: background,operational algorithm and validation, J. Geophys. Res., 17131-17142, 1997.

1998:Alpert P., Kaufman Y.J., Shay-El Y., Tanré D., Da Silva A., Schubert S., Joseph Y.H., Quantification of dust-

forced heating of the lower troposphere, Nature, 395, 367-370, 1998.Dubovik O., Holben B.N., Kaufman Y.J., Yamasoe M., Smirnov A., Tanré D., Slutsker I., Single-scattering

albedo of smoke retrieved from the sky-radiance and solar transmittance measured from the ground, J.Geophys. Res., 31903-31924 , 1998.

Holben B.N., Eck T.F., Slutsker I., Tanré D., Buis J.P. Setzer A., Vermote E., Reagan J.A., Kaufman Y.,Nakajima T., Lavenu F., Jankowiak I. AERONET-A Federated Instrument Network and Data Archive forAerosol Characterization, Rem. Sens. Environ., 66, 1-16, 1998.

Plana-Fattori A., Legrand M., Tanré D., Devaux C., Vermeulen A., Dubuisson P., Estimating of theAtmospheric Water Vapor Content from Sun Photometer Measurements, J. Appl. Meteor., 37, 790-804,1998.

Wald A., Kaufman Y. Tanré D., Gao B.C., Daytime and nighttime detection of mineral dust over desert usinginfrared spectral contrast, J. Geophys. Res., 103, 32307-32313, 1998.

1999:Deuzé J.L., M Herman, P. Goloub, D. Tanré, A. Marchand, Characterization of aerosols over ocean from

POLDER/ADEOS-1, Geophys. Res. Lett., 26, 1421-1424, 1999.Goloub P, D. Tanré, J.L. Deuzé, M. Herman, A. Marchand, F.M. Bréon, Validation of the first algorithm

applied for deriving the aerosol properties over the ocean using the POLDER/ADEOS measurements,IEEE Transactions on Geoscience and Remote Sensing, 37, 1586-1596, 1999.

Hsu N.C., J.R. Herman, O. Torres, B.N. Holben, D. Tanré, T.F. Eck, A. Smirnov, B. Chatenet, F. Lavenu,Comparison of the TOMS Aerosol Index with Sunphotometer Aerosol Optical Thickness: Results andApplications, J. Geophys. Res., 104, 6269-6279, 1999.

Tanré D., L.A. Remer, Y.J. Kaufman, S. Mattoo, P.V. Hobbs, J.M. Livingston, P.B. Russell, A. Smirnov,Retrieval of Aerosol Optical Thickness and Size Distribution Over Ocean from the MODIS AirborneSimulator during TARFOX, J. Geophys. Res., 104, 2261-2278, 1999.

Vesperini M., Bréon F.M., Tanré D., Atmospheric water vapor content from space-borne POLDERmeasurements, IEEE Transactions on Geoscience and Remote Sensing, 37, 1613-1619, 1999.

In pressChiapello I., P. Goloub, D. Tanré, J. Herman, O. Torres, A. Marchand, Aerosol detection by TOMS and

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POLDER over oceanic regions, J. Geophys. Res., accepté, 1999.Kaufman Y.J., A. Karnieli, D. Tanré, Detection of dust over deserts using satellite data in solar wavelengths,

IEEE Transactions on Geoscience and Remote Sensing, accepté, 1999.King M.D., Y. J. Kaufman, D. Tanré, and T. Nakajima, Remote Sensing of Tropospheric Aerosols from Space:

Past, Present, and Future, Bulletin of the American Meteorological Society, accepté, 1999.

(h) Jay R. HermanVita

RESEARCH AREA Ion chemistry, earth ionosphere, planetary ionospheres,EXPERIENCE: wave propagation in plasmas, stratospheric chemistry and modeling,

radiative transfer, atmospheric spectroscopy, uv solar flux measurements,ozone inversion algorithms, and long-term ozone trend analysis.

Recent Experience Instrument design for spaceflight (e.g., Triana spectroradiometer), UVradiation at the EarthÕs surface, aerosols, and cloud properties.

PRESENT POSITION: Project Scientist for Triana missionPrincipal Investigator for TOMS/Meteor project now in post-launchphase.Principal Investigator for FM-5 TOMS projectPrincipal Investigator for TOMS UV and aerosol projectsLead Scientist for TOMS Project Data Acquisition, Validation andAnalysis:

TOMS-SBUV/Nimbus-7 USTOMS/Meteor US/RussiaTOMS/Earth Probes USTOMS/ADEOS US/Japan

Atmospheric Chemistry and Dynamics Branch, NASA/Goddard SpaceFlight Center, Code 916.

EDUCATION: 1959 B.S. Physics with minor in mathematics, (obtained with highhonor) Clarkson College, Potsdam, New York

1963 M.S. Physics Penn. State Univ., State College, PA1965 Ph.D. Physics Penn. State Univ., State College, PA

Recent Publications (1997 to 1999)

1. ÒEarth Surface Reflectivity Climatology at 340 nm to 380 nm from TOMS DataÓ, J. R. Herman and E. A. Celarier,J. Geophys. Res.102, 28003-28011, 1997.

2. ÒGlobal Distribution of UV-Absorbing Aerosols From Nimbus-7/TOMS DataÓ, J.R. Herman, P.K. Bhartia,O.Torres, C. Hsu, C. Seftor, E. Celarier, J.Geophys. Res., 102, 16,911-16,922, 1997.

3. ÒDerivation of Aerosol Properties From Satellite Measurements of Backscattered Ultraviolet Radiation. TheoreticalBasisÓ, O. Torres, P.K. Bhartia, J.R.Herman, and Z. Ahmad, J.Geophys. Res., 103, 17099-17110, 1998.

4. ÒThe Meteor-3/total ozone mapping spectrometer version 7 data set: Cal;ibration and analysisÓ, C.J. Seftor, G.Jaross, J.R. Herman, X.Gu, L. Moy, S.L. Taylor,and C.G. Wellemeyer, J. Geophys. Res., 102, 19,247-19,256, 1997.

5. ÒSatellite estimation of spectral surface UV irradiance in the presence of tropospheric aerosols 1:Cloud free caseÓ,N.A. Krotkov, P.K. Bhartia, J.R. Herman, V. Fioletov, J. Kerr, J. Geophys. Res., 103, 8779-8793 1998.

6. Total ozone/UV-B monitoring and forecasting: Imapct of clouds and the horizontal resolution of satellite retrievalsÓ,J.R. Ziemke., J.R. Herman, J.L. Stanford, and P.K.Bhartia,, J. Geophys. Res., 103, 3865-3871, 1998.

7. ÒNew TOMS instrument measures ozone and aerosolsÓ J. Kaye, R.D. McPeters, J.R. Herman, P.K. Bhartia, and A.J.Krueger, EOS Transactions, AGU, 79, 57, 1998.

8. ÒNIMBUS-7/TOMS detection of mineral dust over the north Africa and the eastern north Atlantic OceanÓ, I.Chiapello, J.R.Herman, C. Hsu, J. Prospero, Accepted by J. Geophys. Res. 1999.

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9. ÒComparisons of the TOMS aerosol index with sun photometer aerosol optical thicknessÓ, N. Christina Hsu, Jay R.Herman, O.Torres, B.N. Holben,D. Tanre, T.F. Eck, A.Smirnov, B. Chatenet, and F. Lavenu, J. Geophys. Res. 104,6269-6279, 1999.

10. ÒThe Distribution of UV Radiation at the EarthÕs Surface From TOMS Measured UV-Backscattered RadiancesÓ,J.R. Herman, N. Krotkov,E. Celarier, D. Larko and G. Labow, J. Geophys. Res. 104, 12059-12076, 1999.

11. UV Radiation an the EarthÕs SurfaceÓ Chapter 9, J. R. Herman, McKenzie, S. Diaz, J. Kerr, S. Madronich, and G.Seckmeyer, WMO 1999, UNEP/WMO Scientific Assessment of Ozone Depletion: 1999, edited by D. L. Albritton,R. T. Watson, and P. J. Aucamp, WMO Global Ozone Res. and Monit. Proj., Geneva, 1999.

12. "Response of the Climatic Temperature to Dust Forcing, inferred from TOMS Aerosol Index and the NASAAssimilation Model", P. Alpert, J. Herman, Y. J. Kaufman and I. Carmona, Atmos. Res., 1999 (accepted).

13. ÒSatellite and ground-based study of 1997 Indonesian forest fire aerosolsÓ, Teruyuki, Nakajima, a. Higurashi, N.Takeuchi, and J.R. Herman, Accepted, Geophysical Research Letters26, 2421_2424, 1999.

14. ÒSatellite detection of smoke aerosols over a snow/ice surface by TOMSÓ, Hsu, N.C., J.R. Herman, J.F. Gleason, O.Torres., C.J. Seftor, Geophys. Res. Lett., 26, 1165-1168, 1999.

15. ÒRegional Changes in Global UV Reflectivity from Clouds and AerosolsÓ, J. R. Herman, D. Larko, and J. Ziemke,submitted to, J. Geophys. Res., 1999.

16. ÒComparison of daily UV doses estimated from Nimbus-7/TOMS measurements and ground-basedspectroradiometric dataÓ, Kalliskota, S., J. Kaurola, P. Taalas, J.R. Herman, E. Celarier, and N. Krotkov, accepted,J. Geophys. Res., 1999.

17. ÒDetermination of Radiative Forcing of Saharan Dust Using Combined TOMS and ERBE DataÓ, N. Christina Hsu,Herman, J.R., and Clark Weaver, submitted to J. Geophys. Res., 1999.

18. ÒSatellite estimation of spectral surface UV irradiance 2: Effect of horizontally homogeneous cloudsÓ, N. Krotkov,Herman, J.R., Bhartia, P.K., Ahmad, Z., Fioletov, V., submitted to J. Geophys. Res., 1999.

19. ÒErythemally weighted UV trends over northern latitudes derived from Nimbus 7 TOMS measurementsÓ, J.R.Ziemke, S. Chandra, J. Herman, and C. Varotsos, submitted to J. Geophys. Res., 1999.

20. ÒQuasi-biennial oscillation in UV-B solar irradiance at Thessaloniki and San Diego from ground-based and satellitemeasurementsÓ, C. Zerefor, M. Tsortziou, J. Herman, A. Bias, submitted to Geophys. Res. Lett, 1999.

8 CURRENT SUPPORT

As specified in Appendices B and A of the NRA, other projects being conducted by the Principal Investigator(PI) are identified by title, funding agency, and ending date, and other support for co-investigators is listed.For projects supported by NASAÕs Office of Earth Science, the subject is described, to distinguish it from theresearch proposed here.

8.1 Principal Investigator, Philip B. Russell

NASA RTOP 229-10-32-00, PI P. Russell. $125,000 in FY99, 10/95-9/00, 2 person-months/17% LoE per year.ÒSAGE III Science Team Activities.Ó Principal activities include developing the SAGE III Aerosol AlgorithmTheoretical Basis Document (ATBD), planning and preparing for validation/correlative measurements, using the new14-channel sunphotometer as a test-bed for SAGE III algorithm development (including ozone-aerosol separation), andinvestigating retrieval algorithms for aerosol particle surface area, volume, and effective radius.

NASA RTOP 622-44-10-10, PI P. Russell. $150,000 in FY99, 10/95-9/99, 3 person-months/25% LoE per year.ÒAerosol Radiative Effect Analyses for TARFOX and ACE 2.Ó Airborne sunphotometer and related data acquired inTARFOX and ACE 2 are analyzed to reduce uncertainties in aerosol effects on climate. PI also serves as InternationalGlobal Atmospheric Chemistry Project (IGAC) Coordinator for TARFOX.

NASA RTOP 622-44-75-10, PI P. Russell. $175,000 in FY99, 10/98-9/01, 3 person-months/25% LoE per year.ÒImproved Exploitation of Field Data Sets to Address Aerosol Radiative-Climatic Effects and Development of a GlobalAerosol Climatology.Ó Airborne sunphotometer and related data acquired in TARFOX and ACE 2 are analyzed toreduce uncertainties in aerosol effects on climate.

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NASA RTOP 621-45-51-10, PI P. Russell. $57,000 in FY99, 10/99-9/00, 2 person-months/17% LoE per year.ÒComposite Data Analyses for Pinatubo Volcanic Aerosols.Ó SAGE II, UARS, and other data are combined to developa composite data set describing the evolution of the Pinatubo volcanic aerosol.

NOAA Interagency Transfer of Funds NAAZ0000700110, PI P. Russell. $99,000 in FY99, 4/97-3/00, 2 person-months/17% LoE per year. ÒEvaluation of the Direct Effects of Anthropogenic Aerosols on the Radiation Balance of theAtmosphere.Ó The Ames 6-channel autotracking sunphotometer and two handheld instruments were installed on a shipfor measurements in ACE 2. Measurements are being analyzed with other data sets to improve understanding of theradiative/climatic effects of European and African aerosols. PI also serves as Co-coordinator for the CLEARCOLUMNcomponent of ACE 2.

8.2 Co-Investigators

8.2.1 Co-Investigators at NASA Ames

Agency/Task No.* Short Title EndDate

Person-Months per Year/ Level of Effort

J.Livingston

B.Schmid

J.Redemann

R.

BergstromNASA RTOP229-10-32-00

SAGE III Science Team 9/00 4/33% 5/42% 1/8%

NASA RTOP622-44-10-10

TARFOX/ACE 2Analyses

9/99 2/17% 2/25% 3/25% 4/33%

NASA RTOP622-44-75-10

TARFOX/ACE 2Analyses in GACP

9/01 2/17% 3/25% 6/50%

NASA RTOP621-45-51-10

SAGE II Science Team 9/00

NOAA InteragencyTransfer of FundsNAAZ0000700110

ACE 2 ShipSunphotometry &

Integrated Analyses

9/99 4/33% 2/17% 2/17% 2/16%

*PI, Award Amount, Period of Performance, Project Title, and Short Abstract are described in preceding Section 8.1.

8.2.2 Other Co-Investigators

Kenneth Voss

ONR (PI K. Voss) 0/1/98 - 9/30/00, $235,651, 2.5 person months/year. “Bi-Directional reflectancemeasurements in the coastal environment”.

NASA (PI Howard Gordon), 1/1/91-12/31/01, $14,648,439 4.5 person months/year. “Ocean observationwith EOS/Modis: Algorithm Development and Post Launch Studies”.

Didier Tanre

Dr. Tanre currently receives no funding from NASA, and no support for him is requested by this proposal.As noted in Section 7, Dr. Tanre’s institution, USTL, has endorsed his participation in NASA researchprojects, and he makes frequent trips to the US for this purpose. He will be available to interact with otherteam members and attend program reviews on these trips.

Jay Herman

37 3:18 PM, 10/20/00

As noted in his vita above, Dr. Herman is a civil servant at NASA GSFC, currently working as ProjectScientist for the Triana mission, Principal Investigator for the TOMS/Meteor project, Principal Investigatorfor the FM-5 TOMS project, Principal Investigator for TOMS UV and aerosol projects, and Lead Scientist forTOMS Project Data Acquisition, Validation and Analysis. This proposal requests no funding for Dr. Hermanpersonally; the time he contributes to the proposed effort (see Section 7) will be covered by his currentprojects at GSFC. To facilitate his contribution, this proposal requests salary and travel support for aprogrammer at GSFC, to provide quick access to TOMS aerosol and ozone data, and to travel to NASA Amesto collaborate with Ames team members regarding TOMS algorithms and validation.

8.3 Other Agencies to Which This Proposal, or Parts Thereof, Have Been Submitted.

No part of this proposal has been submitted to any other agency.

38 3:18 PM, 10/20/00

Table 1. Satellites, Sensors, Data Products, and Planned Field Campaigns Relevant to This Proposal

1 = Primary validation opportunity. 2 = Secondary validation opportunity.3 = Opportunity to investigate effects of strong vertical gradients and dense aerosols on retrievals.

SATELLITESAND

SENSORS

DATAPRODUCTS

FIELD CAMPAIGNS

EOS Terra

SAFARI 2000Third

Campaign,Aug-Sep 2000

African Dust Plume andWater-leaving Radiance

Opportunities on SAFARI2000 Transits, Aug & Sep

2000

ACE Asia Surveyand EvolutionComponent(AA-SEC),

Mar-Apr 2001Aerosol optical

depth spectra &Reff

1 1 1

Normalized water-leaving radiance(Atmos. Corr.)

2 1 1

Water vapor column 1 1 1

MODIS

Ozone column 1 1 1Aerosol optical

depth (4 λ) andtype

1 1 1MISR

Normalized water-leaving radiance(Atmos. Corr.)

2 1 1

CO profile 3 3 3MOPITTCH4 column

ASTER (Atmosphericcorrections useMODIS & MISRgases & aerosols)

2 2 2

CERES Radiances, Albedos,Fluxes

2 2 2

Earth ProbeOzone column 1 1 1TOMSAerosol index 1 1 1

ADEOS IIPOLDER Aerosol optical

depth spectra &Reff

1 1 1

SeaStar,OrbView 2

SeaWiFS Normalized water-leaving radiance(Atmos. Corr.)

2 1 1