BOREASExperiment Plan

Chapter 1Science Background and Objectives

May 1994 Version 3.0

Executive Summary

The good of BOREAS is to improve our understanding of the interactionsbetween the boreal forest biome and the atmosphere in order to clarify theirroles in global change. This document, the BOREAS Experiment Plan(EXPLAN) is the core reference for the field phase of BOREAS. The contentsof the plan are briefly summarized below.

Chapter 1: Science Background, Objectives

The scientific rationale for BOREAS is set out. The principle science issues atstake are the sensitivity of the boreal forest biome to changes in the physicalclimate system; the carbon cycle and biogeochemistry in the boreal forest; andbiophysical feedbacks on the physical climate system. The main objectives ofBOREAS are to:

(i) Improve the process models which describe the exchanges ofenergy, water, carbon and trace constituents between the borealforest and the atmosphere.

(ii) Develop methods for applying the process models over largespatial scales using remote sensing and other integrativemodeling techniques.

Some schematics of the different components of the project (Energy-Waterfluxes, hydrology, carbon cycle, trace gas biogeochemistry and remote sensingscience) are provided as a guide as to how different investigations support thescience.

Chapter 2: Experiment Design and Project Organization

A multiscale approach using a hierarchy of nested spatial scales, and the basisfor the overall experiment design: The experiment covers the followingscales:

Region: A 1000 x 1000 km area covering a largeportion of Saskatchewan and Manitoba.

Study Areas: Two large study areas are embedded in theregion, each of around 10000 km2. TheSouthern Study Area (SSA) located nearPrince Albert, Saskatchewan will focus onprocesses which limit vegetation activity

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near the southern boundary of the borealforest biome, principally soil moisture stressand fire; while the Northern Study Area(NSA) near Thompson, Manitoba will beused to study limiting processes near thenorthern boundary, which are mainly relatedto growing degree days. The NSA and SSAare about 500 km apart.

Transect: Area connecting and including the NSA andSSA.

Modeling Sub-Areas: Tenting ground for modeling activities andgridded data products. These areas have thehighest priority for remote sensing studiesand low-level airborne flux measurements.

Tower Flux Sites: These are sites within the study areas whereflux measurement towers operate. These TFsites are located in the center of areas ofaround 1 km2 of homogeneous vegetationand are expected to measure fluxes(including CO2) representative of the mostimportant vegetation types in the biome.Nine TF sites will operate during 1994.

Auxiliary and ProcessStudy Sites: Around 80 auxiliary and process study sites

are to be used for investigator studies or ascorrelative targets for remote sensinginvestigations.

Maps of the region and the study areas may be found in this chapter.

A monitoring program of meteorological measurements, satellite dataacquisition and some other work started in 1993 and will continue through1995 or 1996. Within the period August 1993 through September 1994, sixfield campaigns were scheduled, each of about 20 days duration, in which thebulk of the science teams will take field measurements. The twelve aircraftinvolved in BOREAS will be taking data over and between the study areasduring this time. The field campaign objectives and dates are summarized inTable 2.1.2 and Figure 2.1.2.

Background information on the vegetation and soil at each TF site may befound in section 2.2.2. Section 2.3 outlines the project organization.

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Chapter 3: Staff Support

BOREAS staff oversee the components of the project that require significantlogistical effort, extended and/or routine monitoring work, or work thatrequires the particular expertise and resources of one of the participatingagencies. The staff monitoring program (section 3.2) includes:

Automatic Meteorological Station NetworkUpper Air NetworkHydrology, snow and soil moistureAuxiliary site workBiometry and allometryRadiometric calibrationStandard gasses and gas calibrationThermal radiance intercomparisonGlobal and Positioning System (GPS) facilities

The satellite data and airborne remote sensing plans are summarized insection 3.2 -- note that this section covers airborne remote sensing instrumentand data processing, not flight operations which are covered in chapter 5. Sitelogistics and infrastructure (including laboratory facilities) are covered insection 3.4 and the BOREAS Information System (BORIS) is reviewed insection 3.5.

Chapter 4: Science Teams

Some 85 science teams are participating in BOREAS. These have beendivided into six disciplinary groups for easier organization doing the fieldphase. The objectives of these six science groups and the science goals of eachinvestigator team are written up in this chapter. The science groups are are asfollows:

Airborne Fluxes and Meteorology (AFM): Four aircraft will be used tomeasure turbulent fluxing, sounding lidars and radars will also be fielded.Several investigators will use mesoscale and global scale atmospheric modelsin their studies of surface-atmosphere interactions.

Tower Fluxes (TF): Nine TF towers will operate during the growing season of1994, measuring radiation, heat, water, CO2 and in some cases CH4 and othertrace gas fluxes. Two of the sites, one in the NSA and one in the SSA willoperate continuously from the fall of 1993 onwards. The layout of each TFsite is shown in Figures 4.2.3.2.

Terrestrial Ecology (TE): Over twenty teams will examine the biophysicalcontrols on carbon, nutrient, water and energy fluxes for the major

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ecosystems in the boreal landscape and will develop logic and algorithms toscale chamber measurements to stand, landscape, and regional scales. Animportant focus for the TE group will be on measuring the components of thecarbon cycle. A number of small towers will be installed in the study areas tofacilitate access to the vegetation canopy for chamber measurements.

Trace Gas Biogeochemistry (TGB): The ten TGB teams will use chambermeasurements and other techniques to characterize the flux of trace gasesbetween the soil and the atmosphere, including CO2, CH4 and NMHC's. TheB group will also measure the long-term accumulation of carbon in borealsoils.

Hydrology (HYD): The HYD group will focus on measurements of snowhydrology, components to support on remote sensing algorithmdevelopment initiative, and will also work on catchment hydrologicalprocesses in the SSA and NSA using precipitation gage networks, streamgagesand a rain radar (SSA only). The HYD group will also support soil moisturemeasurements at the TF sites.

Remote Sensing Science (RSS): The RSS group will develop linkagesbetween optical and microwave remote sensing and boreal zone biophysicalparameters at scales that include leaf, canopy and regional levels using field,aircraft and satellite-borne sensors and a range of radiative transfer models.

Chapter 5: Experiment Execution: The activities planned for the monitoringprogram and field campaigns over the period August 1993 through October1994 are reviewed. The procedures for making decisions and carrying themout are set out.

Section 5.1 covers the management of Experiment Operations. Section 5.2covers aircraft mission plans: a large number of figures and tables describethe details of individual aircraft missions. Figures 5.2.4 show the coverage ofthe region by Landsat and SPOT satellites.

Section 5.3 gives details on planned experiment operations for the fieldcampaigns. The objectives of each campaign are set out and the participatingaircraft and science teams are listed. Chapter 5 serves as the day-to-day guideto BOREAS Mission managers and study area managers in the field.

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Appendices: The titles of each appendix are listed below.

Appendix A: Investigator and Staff AddressesAppendix B: Investigation ProfileAppendix C: Measurement MethodologiesAppendix D: Satellite Overpass ScheduleAppendix E: AcronymsAppendix F: Customs and Shipping Information, Immigration

Formalities, Shipping Destinations, Importation ofPlant and Soil Samples

Appendix G: AccommodationsAppendix H: Traditional Land Use Map and CalendarAppendix I: Memorandum of UnderstandingAppendix J: BOREAS Guidelines for the Conduct of Investigators in

the Field for NSA and SSAAppendix K: BOREAS Check-In/Check-Out ProceduresAppendix L: BOREAS Inter-IFC Survival GuidesAppendix M: BOREAS Modeling ContributionsAppendix N: BOREAS Auxiliary Site DirectionsAppendix O: AES Surface Weather StationsAppendix P: BOREAS Emergency Procedures and Guidelines for SSA

and NSA

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Participating Canadian agencies include the Canada Centre for RemoteSensing, Environment Canada, Natural Sciences and Engineering Council,Agriculture Canada, National Research Council, and Canadian Forest Service.For the United States, the effort is being led by the National Aeronautics andSpace Administration's Mission to Planet Earth, with participation from theNational Oceanic and Atmospheric Administration, the National ScienceFoundation, the United States Geological Survey and the EnvironmentalProtection Agency. BOREAS contributes to both the U.S. and the CanadianGlobal Change Research Programs.

NOTE: BOREAS Investigators participating in field campaigns are required toread.

Section 5.1Appendix KAppendix O

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TABLE OF CONTENTSBOREAS EXPERIMENT PLAN

0.0 Executive Summary

1.0 Science Background, Objectives

1.1 Scientific Issues1.2 Objectives1.3 References

2.0 Experiment Design and Project Organization

2.1 Overview of Approach2.1.1 Multiscale Strategy

2.1.1.1 Hierarchy of Spatial Scales2.1.1.2 Study Area Locations and Mesometerological Network

2.1.2 Duration and Timing of Field Operations2.2 Study Areas and Tower Flux Sites

2.2.1 Sampling Strategy2.2.2 Study Areas

2.2.2.1 Northern Study Area (Thompson, Manitoba)2.2.2.2 Southern Study Area (Prince Albert, Saskatchewan)

2.2.3 Tower Flux Sites2.2.3.1 Northern Study Area Tower Flux Sites2.2.3.2 Southern Study Area Tower Flux Sites

2.3 Project Organization2.3.1 The BOREAS Coordinating Committee (BCC)2.3.2 The BOREAS Executive (BEX)2.3.3 The Science Teams2.3.4 Staff Science and Support

2.4 Overview of Project Resources

3.0 Staff Support

3.1 Overview of Staff Support3.2 Staff Monitoring Program

3.2.1 Automatic Meteorological Stations (AMS)3.2.1.1 AES Surface

3.2.2 Upper Air Network3.2.2.1 ECMWF Operational Products for BOREAS3.2.2.2 Products for BOREAS

3.2.3 Hydrology, Snow and Soil Properties3.2.3.1 Hydrology3.2.3.2 Snow Measurements

3.2.3.3 Soil Survey and Characterization3.2.3.4 Soil Moisture, Temperature and Soil Properties

3.2.4 Auxiliary Site Work3.2.4.1 Approach3.2.4.2 Requirements3.2.4.3 Stratification3.2.4.4 Site Selection3.2.4.5 Measurements

3.2.4.5.1 Tower flux annex sites3.2.4.5.2 Carbon budget modeling sites3.2.4.5.3 Radiative transfer study sites3.2.4.5.4 Carbon model evaluation sites3.2.4.5.5 Intensive allometry sites3.2.4.5.6 Remote sensing/modeling study sites

3.2.4.6 Hemispherical Photography3.2.4.7 Soil sampling at the auxiliary sites3.2.4.8 Schedule

3.2.5 Radiometric Calibration3.2.5.1 Aircraft and Remote Sensing Instrumentation

3.2.5.1.1 Radiometric Scale Realization3.2.5.1.2 On Site Radiometric and Spectral

Calibration Sources3.2.5.1.3 Diffuse Reflectance Reference Panels3.2.5.1.4 In-Flight Calibration and Comparison

of Aircraft Instrumentation (R. Green,NASA/JPL)

3.2.5.2 Satellite Sensors3.2.6 Standard Gasses and Gas Calibration3.2.7 BOREAS Thermal Radiance Measurement Intercomparison

Plan3.2.8 Global Positioning System (GPS)

3.3 Satellite and Airborne Remote Sensing3.3.1 Satellite Image Data Plan

3.3.1.1 Landsat and SPOT3.3.1.2 AVHRR-LAC3.3.1.3 ERS-13.3.1.4 GOES3.3.1.5 JERS-13.3.1.6 SIR-C/X-SAR

3.3.2 Airborne Sensor Data Plan3.3.2.1 C-130/MAS; Staff (Ungar)3.3.2.2 C-130/ASAS; RSS-2 (Irons)3.3.2.3 C-130/NS001-TMS, Staff (Angelici)3.3.2.4 C-130/ATSP; RSS-12 (Wrigley)3.3.2.5 CV-580/SAR; RSS (Ranson); Staff-CCRS (Cihlar/Hawkins)3.3.2.6 DC-8/AIRSAR; RSS-16 (Saatchi)

3.3.2.7 Twin Otter/AMMR; HYD-2 (Chang)3.3.2.8 ER-2/AVIRIS; RSS-18 (Green)3.3.2.9 ER-2/Airborne Ocean Color Imager/TE-15 (Bukata)3.3.2.10 ER-2/MAS; Staff (Ungar, D.K. Hall), Modland3.3.2.11 Piper Chieftain/CASI; RSS-19 (Miller)3.3.2.12 DC-3/MEIS II; Staff-CCRS (Gauthier)/RSS-7 (Chen)3.3.2.13 Helicopter/C-band Scat; Staff (Gogineni)3.3.2.14 Helicopter/SE-590; RSS-3 (Walthall), TE-18 (Hall)3.3.2.15 Aerocommander/Gamma Radiation: HYD-6 (Peck) HYD-4

(Goodison)3.4 Site Logistics and Infrastructure

3.4.1 Infrastructure for Tower Flux Sites3.4.2 Laboratory Facilities

3.5 The BOREAS Information System (BORIS)3.5.1 Role of BORIS3.5.2 The BORIS Working Group3.5.3 General Policies

3.5.3.1 Data Policy3.5.3.2 Data Documentation3.5.3.3 Data Quality Assurance3.5.3.4 Data Plans

3.5.3.4.1 Proposed AFM Data Plan3.5.3.4.2 Proposed TF Data Plan3.5.3.4.3 Proposed TE Data Plan3.5.3.4.4 Proposed TGB Data Plan3.5.3.4.5 Proposed HYD Data Plan3.5.3.4.6 Proposed RSS Data Plan

3.5.3.5 Data Delivery3.5.3.6 Data Standards

3.5.4 Mapping and Site Location3.5.4.1 BORIS Grid3.5.4.2 BOREAS Operational Grid

3.5.5 Gridded Data Products3.5.6 Data Access3.5.7 Satellite Image Data Products3.5.8 BOREAS Data Documentation Outline

4.0 Science Teams

4.1 Airborne Flux and Meteorology (AFM)4.1.1 Objectives4.1.2 Investigation Summaries4.1.3 Field Measurements

4.1.3.1 In-Situ Measurements4.1.3.1.1 Overview4.1.3.1.2 Strategies and priorities of aircraft flux

measurements4.1.3.1.3 Aircraft-tower comparisons4.1.3.1.4 Role and effects of lakes4.1.3.1.5 Possible impacts of abrupt land-use

and land-cover boundaries4.1.3.1.6 Importance of modeling studies4.1.3.1.7 Footprints and intrasite variability4.1.3.1.8 Candle Lake Modelling and Measurement

4.1.3.2 Data to be submitted to BORIS4.1.3.3 Special Concerns of AFM Field and Modeling Investigations

4.1.4 Supporting Measurements4.1.4.1 Needs from other groups4.1.4.2 Support and staff science needs identified by AFM

4.1.5 Internal Organization4.2 Tower Flux (TF)

4.2.1 Objectives4.2.2 Investigation Summaries4.2.3 Field Measurements

4.2.3.1 In-Situ Measurements4.2.3.2 Data to be submitted to BORIS

4.2.4 Supporting Measurements4.2.4.1 Needs from other groups4.2.4.2 Needs from staff science

4.2.5 Next Steps4.2.5.1 1993 and 1994 Activities4.2.5.2 TF Internal Organization

4.3 Terrestrial Ecology (TE)4.3.1 Objectives4.3.2 Investigation Summaries4.3.3 Field Measurements

4.3.3.1 In-Situ Measurements4.3.3.2 Biometry Measurements

4.3.3.2.1 Biometry Work Plan4.3.3.2.2 Allometry Measurements4.3.3.2.3 Aboveground Biomass and Net Primary

Production4.3.3.2.4 Biometry and Allometry Measurements to be

made at auxiliary sites4.3.3.3 Canopy Access and Destructive Sampling Needs

4.3.3.3.1 Canopy Access4.3.3.3.2 Destructive Sampling Needs

4.3.3.4 TE Investigators' Field Visits Schedules4.3.4 Experiment Protocols

4.3.4.1 Soil CO2 flux measurements at BOREAS

4.3.4.2 Procedures for measuring and reporting foliage area 4.3.5 TE Modelling, Scaling and Links to RS

4.3.5.1 Comparison between models and tower fluxes4.3.5.2 The auxiliary sites: testing light use efficiency models and

forest-BGC4.3.5.3 Landscape fluxes4.3.5.4 Regional fluxes4.3.5.5 Mixed stand4.3.5.6 Working group

4.3.6 Internal Organization4.4 Trace Gas Biogeochemistry (TGB)

4.4.1 Objectives4.4.2 Investigation Summaries4.4.3 Field Measurements

4.4.3.1 In-Situ Measurements4.4.3.2 Data to be submitted to BORIS

4.4.4 Supporting Measurements4.4.4.1 Needs from other groups4.4.4.2 Needs from staff science4.4.4.3 Minimal Ancillary Field Measurements to Accompany

Flux Measurements4.4.5 Internal Organization

4.5 Hydrology (HYD)4.5.1 Objectives4.5.2 Project Summaries4.5.3 Field Measurements

4.5.3.1 In-Situ Measurements4.5.3.1.1 Overview4.5.3.1.2 Summary of Project Data Collection Plans4.5.3.1.3 Study Gaps

4.5.3.2 Data to be submitted to BORIS4.5.4 Supporting Measurements

4.5.4.1 Needs from Other Groups or Core Measurements4.5.4.2 Additional Core Data Collection Needs

4.5.5 Coordination and Other Issues4.5.5.1 1993 Activities4.5.5.2 Coordination with other groups4.5.5.3 Interdisciplinary Working Groups

4.6 Remote Sensing Science (RSS)4.6.1 Objectives4.6.2 Investigation Summaries4.6.3 Field and Aircraft Measurements

4.6.3.1 Summary of Parameters to be Measured4.6.3.2 TE/RSS Gridded Parameter and Modeling Initiative4.6.3.3 Data to be Submitted to BORIS (Deliverables)

4.6.4 Supporting Measurements

4.6.4.1 RSS Group Data Needs4.6.4.2 RSS Group Infrastructure Needs

4.6.5 Next Steps4.6.5.1 1993 Activities4.6.5.2 Internal Organization

5.0 Experiment Execution5.1 Management of Experiment Operations

5.1.1 Overview5.1.2 Decision Making5.1.3 Operations Management Roles and Responsibilities

5.1.3.1 BOREAS Mission Manager (MM)5.1.3.2 Study Area Manager (SAM)5.1.3.3 Team Chairs/Representatives5.1.3.4 TF and TE Site Captains5.1.3.5 Field Liaison and Site Managers/Contacts5.1.3.6 Laboratory Chiefs5.1.3.7 Aircraft Managers5.1.3.8 Investigators5.1.3.9 Meteorological Forecaster

5.1.4 Meeting Schedules and Formats5.1.5 Aircraft Operations Protocols5.1.6 Communications

5.1.6.1 Aircraft Radio Net5.1.6.2 Ground Radio Net5.1.6.3 Telephone/Faxes

5.1.7 Emergency Procedures and Safety5.1.7.1 Emergency Procedures5.1.7.2 Safety

5.2 Mission Plans5.2.1 Individual Aircraft Mission Plans5.2.1c Reference Table for Decoding BOREAS Aircraft Mission Identifiers

5.2.1.1 C-130 (RC)5.2.1.1.1 RC-SN and RC-SS Snow Mission in FFC-T5.2.1.1.2 RC-TN and RC-TS: ASAS, POLDER, TMS

Mission Over TF Sites5.2.1.1.3 RC-MN and RC-MS: NSA and SSA Mapping:

TMS, POLDER, MAS5.2.1.1.4 RC-RT: Regional Transect; TMS, MAS

5.2.1.2 DC-8 (RD)5.2.1.3 CV-580 (RV)5.2.1.4 DH-6 (RT)

5.2.1.4.1 RT-SN: Snow Microwave, NSA5.2.1.4.2 RT-ST: Snow Microwave, Transect5.2.1.4.3 RT-SS: Snow Microwave, SSA

5.2.1.5 ER-2 (RE)5.2.1.5.1 RE-US: ER-2 MAS Snow Survey, SSA

5.2.1.5.2 RE-MS: Mapping of SSA5.2.1.5.3 RE-MN: Mapping of NSA, Transect5.2.1.5.4 RE-SS: Snow over flights of SSA during single

pass AVIRIS5.2.1.5.5 RE-SN: Snow over flights of NSA during FFC-T

5.2.1.6 Chieftain (RP)5.2.1.6.1 RP-TS: Tower/auxiliary sites, SSA5.2.1.6.2 RP-TN: Tower/auxiliary sites, NSA5.2.1.6.3 RP-SS Snow lines, SSA5.2.1.6.4 RP-SN: Snow lines, NSA5.2.1.6.5 RP-RT: Coverage of regional transect

5.2.1.7 DC-3 (RF)5.2.1.7.1 RF-TS: TF sites in SSA5.2.1.7.2 RF-TN: TF sites in NSA

5.2.1.8 Aerocommander (RA)5.2.1.8.1 RA-SN: Snow Survey, NSA5.2.1.8.2 RA-ST: Snow Survey, Transect5.2.1.8.3 RA-SS: Snow Survey, SSA5.2.1.8.4 RA-WT: Soil Moisture Survey, Transect5.2.1.8.5 RA-WS: Soil Moisture Survey, SSA

5.2.1.9 NASA Helicopter (RH)5.2.1.9.1 RH-TS or RH-TN: Passive Optical Mission (3

hours)5.2.1.9.2 RH-BS or RH-BN: Microwave Scatterometer

Data Collection (3 hours)5.2.1.10 Flight Plans for Flux Aircraft Operations in 1994 IFCs

5.2.1.10.1 Fx-CL: Candle Lake Runs5.2.1.10.2 Fx-TS, Fx-TN: Site-Specific, Short Passes5.2.1.10.3 FE-RT: Electra Transects5.2.1.10.4 Fx-MS, Fx-MN: Mini-/Meso-Scale Transects and

L-shaped patterns5.2.1.10.5 Fx-GS, Fx-GN: Grid and Stack5.2.1.10.6 Fx-PS, Fx-PN: Budget Box5.2.1.10.7 Fx-HS, Fx-HN: Stacks and Tees5.2.1.10.8 Fx-FS, Fx-FN: Flights-of-Two5.2.1.10.9 Fx-ZS: Low Level Routes

5.2.2 Mission Strategies5.2.3 Flight Hours and Basing5.2.4 Satellite Schedule

5.3 Experiment Operations5.3.1 IFC-935.3.2 FFC-W5.3.3 FFC-T5.3.4 IFC-15.3.5 IFC-25.3.6 IFC-3

APPENDICES

Appendix A: Investigator and Staff AddressesAppendix B: BOREAS Emergency Procedures and Guidelines for SSA

and NSAAppendix C: BOREAS Check-In/Check-Out ProceduresAppendix D: BOREAS Inter-IFC Survival GuidesAppendix E: Customs and Shipping Information, Immigration

Formalities, Shipping Destinations, Importation ofPlant and Soil Samples

Appendix F: Agreement between United States and CanadaAppendix G: AccommodationsAppendix H: BOREAS Guidelines for the Conduct of Investigators in

the Field for NSA and SSAAppendix I: BOREAS Auxiliary Site DirectionsAppendix J: BOREAS Modeling ContributionsAppendix K: Measurement MethodologiesAppendix L: AES Surface Weather StationsAppendix M: Traditional Land Use Map and CalendarAppendix N: Investigation ProfileAppendix O: Satellite Overpass ScheduleAppendix P: Acronyms

1.0 SCIENCE BACKGROUND, OBJECTIVES

The goal of BOREAS is to improve our understanding of the interactionsbetween the boreal forest biome and the atmosphere in order to clarify their rolesin global change.

1.1 Scientific Issues

The scientific issues at stake are as follows.

I. Sensitivity of the boreal forest biome to changes in the physical climatesystem. A number of simulation studies have been carried out to assessthe climatic impact of increasing atmospheric CO2, see the reviews ofSchlesinger and Mitchell (1987) and Harrington (1987). Many of thesestudies indicate that the greatest warming engendered by increasing CO2

will occur at higher (45oN-65oN) latitudes with the most marked effectswithin the continental interiors; for example, the doubled-CO2 experimentof Mitchell (1983) produced differences of 3K to 10K in the mean wintersurface temperature for much of the land surface area of this zone. Otherstudies have indicated that there may be significant warming and dryingin the summer months in the same region. Studies by Davis and Botkin(1985) and Solomon and Webb (1985) suggest that this warming and dryingcould modify the composition and functioning of the boreal forest, seeFigure 1.1

II. The carbon cycle and biogeochemistry in the boreal forest. The study ofTans et al. (1990) presents evidence for the existence of a large terrestrialsink for fossil fuel carbon in the mid latitudes of the NorthernHemisphere The exact mechanisms involved and the spatialcontributions to this sink are as yet unknown, but the implication is thatcarbon is being stored in either living tissue or in the soil. However, anysustained increase in surface temperature, combined with changes in soilmoisture, could result in changes in the cycling of nutrients in the soilswith associated releases of CO2, CH4 and other trace gases from the surface.If this occurs on a large enough spatial scale, the oxidative capacity of thelower atmosphere could be significantly altered. Additionally, changes inthe temperature and moisture regime could alter the biomes exposure andresponse to discontinuous disturbance, i.e. fire frequency, which couldsubstantially affect the carbon cycle within the biome. As yet, we do notknow enough about important processes within the region to be able topredict or even simulate the carbon source/sink dynamics there.

III. Biophysical feedbacks on the physical climate system. Research work hasindicated (See I. above) that changes in the ecological functioning of thebiome could be brought about by changes in the physical climate system. It

1-1

is anticipated that these may be accompanied by alterations in thebiophysical characteristics of the surface; namely albedo, surface roughnessand the biophysical control of evapotranspiration (surface and internalresistance). Any changes in these may have feedback effects on the near-surface climatology (temperature, humidity, precipitation and cloudinessfields), see Sato et al. (1989).

Further discussion of the larger scientific issues framing BOREAS may be foundin the BOREAS Science Plan (Sellers, et al; 1991).

The focus of BOREAS is a cooperative field experiment involving land surfaceclimatology, biogeochemistry and terrestrial ecology components with remotesensing playing a strong integrating role. A coordinated approach to theexperiment design and execution has been adopted from the outset to ensure themaximum benefit from each discipline's participation.

1.2 Objectives

The overall goal of BOREAS is to improve our understanding of the interactionsbetween the boreal forest biome and the atmosphere in order to clarify their rolesin global change.

The immediate experimental phase of BOREAS is planned to run for two tothree years. Obviously, this is too short a period for us to observe the effects ofglobal change directly but it will allow us to observe important processes under awide range of conditions so that we can develop and test key process models.The strategy of the experiment is specifically directed toward this: first,measurements will be taken throughout the year at a variety of 'representative'sites to characterize the meteorological regimes and ecophysiological conditionsto be found in the region. These measurements will be used initially to improveour process models. Second, remote sensing and integrative modellingtechniques will be used to apply these process models over large areas to see howwell we can describe the present situation. If this can be done convincingly overone or two annual cycles, then we will have more confidence in applying ourmodels as predictive tools to address the issues listed in Section 1.1. In addition,the knowledge gained should enable us to design a better, more cost-effectivelong-term monitoring program to track future changes in the biome andsubsequent interactions between the forest and the physical climate system. Thegoverning objectives of BOREAS can therefore be stated as follows:

(I) Improve the process models which describe the exchanges of energy,water, heat, carbon and trace constituents between the boreal forest and theatmosphere.

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This will be done by measuring fluxes over a wide range of spatial scalestogether with observations of the ecological, biogeochemical, andatmospheric conditions controlling them. The process models will bedeveloped and thoroughly tested before they can be applied to the 'globalchange' issues described above.

The initial focus will be on validation and improvement of local-scale(site to landscape) energy balance, mass balance and biophysical processmodels that operate at relatively short time scales (seconds to seasons) andwhich are amenable to measurement within a two year field program.The results of this effort will also be useful for the study of ecosystem leveldynamics and land surface/climate interactions at regional and local scalesover longer time periods (years to decades).

The necessary field observations include measurements of fluxes of thesequantities at the plot or leaf scale (chambers, porometers), the stand scale(tower mounted devices) and the mesoscale (airborne eddy correlation).These observations will be coordinated with a series of ecological,meteorological and edaphic measurements which will quantify the statevariables controlling the fluxes.

(II) Develop and test methods for applying the process models over largespatial scales using remote sensing and integrative modeling techniques.

This objective will be addressed by ensuring close coordination of theprocess studies described in (I) above with remote sensing investigationsusing satellite, airborne and surface-based instruments. These focusedremote sensing studies, combined with mesoscale meteorological studies,will allow us to scale-up and apply the process models at regional andultimately global scales. There are some large-scale validation techniquesat our disposal to test these scale-integration methods explicitly, includingairborne eddy correlation and meteorological observations.

The two governing objectives described above provide the overall framework forthe project. Figures 1.2a through 1.2j show schematically how measurementstaken at different scales support the overall objectives in the areas of atmosphericenergy-water fluxes, carbon cycle, surface hydrology, trace gas biogeochemistry,and remote sensing science. These studies are aimed at quantifyinginitial/boundary conditions and mechanisms associated with the importantecological processes (i.e. ecophysiological and edaphic) which govern theinteractions between the boreal forest and the atmosphere.

Each pair of figures (e.g., 1.2a and 1.2b) shows how the measurements fit togetherat different scales and then how individual investigations contribute

1-3

Figure 1.1 Important interactions between the boreal forest and theatmosphere with respect to global change

(A) Influence of changes in the Physical Climate System on biophysicalprocesses. These may feedback to the atmosphere through changesin energy, heat, water and CO2 exchange.

(B) Changes in nutrient cycling rates; release of CO2 and CH4 from thesoil carbon pool back to the atmosphere.

(C) Changes in biogeochemical processes and water and nutrientavailability influence community composition and structure.

(D) Change in species composition results in changes in surfacebiophysical characteristics and biogeochemical process rates.

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to the work. Figures 1.2 are focused on the measurements aspects of BOREAS,but some of the modeling contributions are also shown where appropriate.More information on the investigations can be found in Chapter 4 and theAppendix.

To develop the detailed design of the experiment, objectives I and II weretranslated into a set of specific supporting sub-objectives.

(i) Test the limits and sensitivity of different surface energy and mass (H2Oand CO2) balance modeling approaches. The models are to be forced bymeteorological and remote sensing data. This involves the calculation ofstate variables from remote sensing and the in-situ measurement of heat,mass and energy fluxes for model validation.

A specific goal is to construct models and collect data which will allow theestimation of the principal terms in the carbon budget for a number ofsites at spatial scales of meters to a few kilometers and time scales out to ayear or so, see figures 1.2a through 1.2f, 1.2h and 1.2j.

The essential observational components for this include:

• Measurement of radiation budget terms.

• Measurement of the turbulent fluxes of sensible heat, water vapor,CO2 and momentum using chambers or enclosures (whereappropriate), towers and airborne instrumentation combined withina nested, multiscale sampling strategy.

• Measurement of important state variables (e.g. surface cover type,fraction of PAR absorbed by the canopy, leaf area index, soil moisture,etc.) in such a way as to allow direct comparison with the radiationand flux measurements described above and the appropriate remotesensing measurements described below.

• Measurement of meteorological variables (temperature, humidity,precipitation, wind speed, cloud cover, etc.) using a coarse mesoscalenetwork of surface stations and profilers grouped around andbetween the intensive study sites.

• Measurement (if possible) of key hydrological variables (soilmoisture, stream flow, snow water equivalent, above and belowcanopy precipitation, evapotranspiration) with the aim of closing thewater balance of gauged catchments within or including the studyareas.

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• Remote sensing of atmospheric and surface state variables associatedwith the above using surface and airborne instruments (for directcorrelative studies) and satellite sensors.

The modeling component of this effort may include the construction,validation and application of the following types of models.

• Biophysical models (soil-plant-atmosphere models) which describethe absorption and partition of energy by the surface on the spatialscale of the flux measurements.

• Models of the carbon budget, ranging from short time scale, smallspace scale photosynthetic models; out to landscape scale models ofcarbon flow which address gains from photosynthesis and losses byrespiration, fire and runoff.

• Mesoscale meteorological models, which may have elements of theabove two classes of models embedded within them, to (i) synthesizethe regional-scale fields of surface - atmosphere fluxes for comparisonwith remote sensing and airborne eddy correlation data, (ii) provide aregional context for the detailed site studies and (iii) explore theimpact of the spatial arrangement of regional-scale flux fields on thephysical climate system.

• Hydrological models, operating over the entire range of spatial scalesaddressed by BOREAS (meters to tens of kilometers), to (i) provide anindependent check on the water budget over a longer time scale and(ii) contribute to the 'scaling up' procedure in concert with theremote sensing and mesoscale modeling efforts.

(ii) Study the exchange and the processes governing the exchange of tracegases between the boreal forest and the atmosphere with reference to thediurnal and seasonal variability of the energy and moisture fluxes to theecosystem, see Figures 1.2e through 1.2h.

The following particular issues will be addressed:

• Carbon dynamics, emphasizing the role of environmental controlson carbon storage and fluxes. This will involve direct measurementsof CO2, CH4, and CO fluxes over a 1 to 2 year period with the aim ofdescribing the annual carbon budget of selected sites. This work willbe coordinated with studies of moisture and energy fluxes and withstudies of carbon storage in the soils.

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• Methane (CH4) dynamics, based on the recognition that the borealforest can be both a source and a sink of CH4.

• Seasonal differences in the chemistry of the boreal troposphere,particularly to determine whether the winter troposphereaccumulates reactive nitrogen and to contrast seasonal pollutantloadings.

• The dynamics of short-lived gases, such as O3, NOx, CO and NMHC.

• The dynamics of biogenic hydrocarbons: factors controlling theemission and degradation of isoprene, terpenes and oxygenatedhydrocarbons and their role (in combination with other gases) in theoxidation cycles of the lower troposphere.

• The role of fires in determining tropospheric chemistry.

• Direct quantification of the fluxes of radiatively important trace gasesand those gases which could affect the oxidant balance of thetroposphere.

• Direct quantification of the fluxes of radiatively important trace gasesand those gases which could affect the oxidant balance of thetroposphere.

(iii) Investigate the relationship between the fluxes of energy, heat, mass,momentum and trace gases on the one hand and ecosystem successionalstate and nutrient dynamics on the other hand, including the effects ofpossible feedbacks from the atmosphere to the surface, see Figures 1.2ethrough 1.2h.

This will require a number of intensive ecological studies coordinatedwith the flux and state variable measurement efforts described above. Theaim is to produce ecological models that may be partly driven by remotesensing and meteorological/climatological data and which explore (a) thefate of assimilated carbon, (b) the limits on assimilation, allocation andrespiration imposed by climate and nutrient cycling controls, and (c) theexpression of (a) and (b) in the growth and development of differentvegetation - soil complexes. Measurements include:

• State variables (cover type, biomass, leaf area index, canopy and soilchemistry, age class distribution, etc.).

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• Nutrient status and cycling rates using in-situ observations andperhaps small scale (less than 100 x 100 m) manipulationexperiments.

• Ecophysiological measurements (leaf photosynthesis, stomatalconductance, canopy FPAR, leaf water potential, etc.).

• Studies of the fate of assimilated carbon, including allocation andrespiration by vegetation, soil fauna and macrofauna. The impact ofkey species on nutrient and carbon cycling rates should be studied.

(iv) Develop and evaluate remote sensing algorithms that relate parameterdrivers associated with all of the above models to spectral, spatial andtemporal patterns of surface radiance fields, see Figures 1.2i and 1.2j.

Remote sensing will contribute to BOREAS in two principal ways:

(a) Upscale integration of models and parameter fields: If links betweenremotely-sensed signatures and key atmospheric and surfacestate/process variables and parameters can be established andvalidated at the intensive study sites, a combination of remotesensing, mesoscale meteorological modeling and other spatialintegration/interpolation techniques should allow an extension ofthe knowledge gained at the experimental site scale out to regionalscales.

(b) Landscape characterization and dynamics: The distribution,characteristics, and temporal dynamics of the boreal vegetation covertypes can be established through archived and newly acquired satellitedata. The historical record of Landsat data, to give one example,extends back for over twenty years. The temporal and spatial scope ofsatellite data provides us with a unique classification tool that can beused to study the dynamics of vegetation communities (growth,senescence, succession, fire, etc.) over a wide range of scales. Again,these data will help to place the intensive study sites in their correctcontext in relation to the biome as a whole.

Goals and methods of the remote sensing element of BOREAS arereviewed in more detail in Hall et al. (1993).

To make the best use of satellite data, the following studies need to beconducted:

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• Correlative remote sensing measurements linked to the principalprocess/state variable studies described above, using surface, airborneand satellite sensors (active and passive).

• Measurements of the atmospheric state, to allow correction of theremotely sensed data.

• Modeling studies, to establish the physical links between observedradiances/emittances and surface or atmospheric states and processes(e.g. construction of radiative transfer models to explore how visibleand near-infrared reflectances can be used to calculate canopy FPAR).

• Evaluation studies, to determine the limits of accuracy with whichimportant parameters can be estimated for a range of different surfaceand atmospheric conditions and a range of spatial scales.

A full year of data acquisition is scheduled for 1994. Also in 1994, somepreliminary modeling intercomparison work will be carried out. Modelers froma number of different groups will run Soil Vegetation Atmosphere Transfermodels on the same test data set to learn more about behavior and sensitivity,see Appendix J. During 1995, data reduction, analyses, and modeling work willmove ahead in parallel with a reduced set of field observations. If necessary,there may be a return to the field in 1996.

1.3 References

Davis, M.B., and D.B. Botkin, 1985: Sensitivity of cool temperate forests and theirfossil pollen to rapid climatic change, Quaternary Research, 23: 327-340.

Hall, F. G. , P. J. Sellers, M. Apps, D. Baldocchi, J. Cihlar, B. Goodison, H.Margolis, A. Nelson (1993): "BOREAS: Boreal Ecosystem-Atmosphere Study",IEEE Geoscience and Remote Sensing Society Newsletter, March 1993, 9-17.

Harrington, J.B., 1987: Climatic change: a review of causes, Canadian Journal ofForest Research, 17: (11), 1313-1339.

Mitchell, J.F.B., 1983: 'The seasonal response of a general circulation model tochanges in CO2 and sea temperature,' Quart J. Roy. Met. Soc., 109: 113-152.

Sato, N., P.J. Sellers, D.A. Randall, E.K. Schneider, J. Shukla, J.L. Kinter III, Y-THou and E. Albertazzi, 1989: 'Effects of implementing the Simple BiosphereModel (SiB) in a general circulation model', J. Atmos Sci. 46: 2757-2782.

Sellers, P. J. , J. Cihlar, M. Apps, B. Goodison, F. G. Hall, R. C. Harriss, D. L. Leckie,E. Ledrew, P. A. Matson and S. Running (1991), "BOREAS - Boreal Ecosystems -

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Atmosphere Study: Global Change and Biosphere - Atmosphere Interactions inthe Boreas Forest Biome - Science Plan", 923, NASA/GSFC, Greenbelt, Maryland,USA, 20771, pp. 67.

Schlesinger, M.E. and J.F.B. Mitchell, 1987: Climate model calculations of theequilibrium climatic response to increased carbon dioxide, Reviews ofGeophysics, 25: (4), 760-798.

Solomon, A.M., and T. Webb III, 1985: Computer-aided reconstructions of late-Quaternary landscape dynamics, Annual Review of Ecology and Systematics, 16:63-84.

Ans, P.P., I.Y. Fung and T. Takahashi, 1990: "Observational Constraints on theglobal atmospheric CO2 budget," Science 247: 1431-1438.

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1.2.a Schematic of processes associated with energy and water fluxes in theboreal forest.

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ENERGY-WATER FLUXES

Physical Climate System Models

GCMs: AFM-9, 14, 15NWP: AFM-8, AFM-11

Mesoscale Models

AFM-11, 12, 13

GLOBAL

RemoteSensingScience (RSS)

Meteorological obsSurface: AFM-7, TF-2, 3Soundings: AFM-5, 6Airborne Fluxes: AFM 1-4

MESOSCALERadiation

Satellite: RSS-10, 14Surface: AFM-7

Precipitation

HYD-8,9; AFM-7

LOCAL SCALE FLUXES

Aiborne Eddy Correlation

AFM-1 through AFM-4

Tower Fluxes

TF-1 through TF-11

Hydrology

HYD-1,6,8,9

Surface Controls

Soil Surface Fluxes

TGB, TETF-1, 5

Ecophysiology

ConductancePhotosynthesisTE-4, 5, 7, 8, 9,10, 11, 12

Soil Moisture

HYD-1,6,8,9PLOT

LOCAL

1.2.b Flow chart corresponding to 1.2.a, showing roles of BOREAS investigators.

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1.2.c Schematic of processes associated with hydrology in the boreal forest.

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Physical ClimateSystem

AFM, TF Groups(see figures 1.2a, b)

HydrometeorologyMeasurements

Meteorology AFM-5,7; HYD-9, Streamflow: HYD-9

Surface Fluxes

Measurements: AFM (TF, TGB); HYD-5

Surface Radiation

Measurements: HYD-2,HYD-3, RSS, TF

LOCAL

HYDROLOGY

Hydrological System State

Snow: HYD-2, 3, 4, 5, 6, RSS-16Modeling HYD-8, 9

Soil Moisture: HYD-1, 3, 6, TF-1, 3, 5, 9, 10 TGB-4, TE-1, StaffCanopy Interception: HYD-8Modeling: HYD-8, 9

MESOSCALE

REGIONALRemoteSensingScience(RSS)

1.2.d Flow chart corresponding to 1.2.c, showing roles of BOREAS investigators.

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1.2.e Schematic of processes associated with the carbon cycle in the borealforest.

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CARBON CYCLE

RemoteSensingScience(RSS)

Regional Fluxes

Measurements: AFM-1, 2, 3, 4Models: AFM-11, 14; TE-14, 16, 17, 18, 19, 20, 21, 22

Tower Fluxes

Measurements: TF-1 through TF-11Models: TE-4, 5, 6, 7, 9, 10, 13, 14, 16, 17, 18, 21, 22

Canopy Fluxes

Photosynthesis : TE-4, 5, 7, 8, 9, 10, 11, 12Respiration : TE-2NMHC : TGB-8, 10NPP, Litterfall : TE-6, 7Roots : TE-6, 7Lakes : TE-15Models : see Tower Fluxes

PhysicalClimateSystem

Soil Fluxes

CO2, CH4, COTGB-1, 3, 4, 5, 6, 12TF-4, 5, 11TE-1, 5, 6, 7Models: see Tower Fluxes

Dissolved Organic CTF-4, TGB-3

REGIONAL

LOCAL

PLOT

1.2.f Flow chart corresponding to 1.2.e showing roles of BOREAS investigators.

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1.2.g Schematic of processes associated with trace gas biogeochemistry in theboreal forest.

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TRACE GAS BIOGEOCHEMISTRY

Regional Fluxes, Concentrations

CO2, CH4, etc.: AFM-3Pesticides: TGB-7

Mesoscale Fluxes

CO2, CH4: AFM-2, 3, 4

Tower Fluxes

CO2: TF-1 through TF-11CH4: TF-1, 2, 3, 4, 11

Trace Gas Samplings

NMMC: TGB-8, 9O3, NOx: TGB-9

Trophic

Fens, BogsTGB-3, 4, 6

Moisture

Upland/WetlandTGB-1, 3, 12

Soil Type

TGB-1, 12

Disturbance

Fire, beaversTGB-1, 4, 5

DOC Export, burial

TF-4, TGB-4, 12

PLOT

LOCAL

MESOSCALE

REGIONALRSS

RemoteSensingScience

1.2.h Flow chart corresponding to 1.2.f showing roles of BOREAS investigators.

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1.2.i Schematic of tasks associated with remote sensing science in BOREAS.

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REMOTE SENSING SCIENCE

GCM: Model Boundary ConditionsSurface Radiation Budget: RSS-14FPAR, LAI, Cover: TE-18, USGSCanopy structure, moisture: RSS-15, 16Snow Cover: HYD-4Models: RSS, TE, AFM groups

Surface Fields

FPAR, LAI Cover: RSS-2, ARC, RSS-18, 20Atmospheric Correction: RSS-10, 11, 12Canopy Structure, Moisture: RSS-15, 16, 17Freeze Thaw: RSS-17

REGIONAL

MESOSCALE

Point Measurements

Airborne VIS/NIR: RSS-2, 3, 7, 8, 9, 19, 20Surface VIS/NIR: RSS-1Airborne Backscatter: RSS-13Surface FPAR: TE-23Models: RSS-1, 2, 3, 4, 5, 6, 7, 8

LOCAL

Element Measurements

Foliage reflectance: TE-9, 10, 12, RSS-4Lake chlorophyll: TE-15

PLOT

1.2.j Flow chart corresponding to 1.2.i showing roles of BOREAS investigators.

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