NEWS NEWSWorld Climate Research Programme__WCRP

Vol. 10, No. 3 August 2000

Global Energy and Water Cycle Experiment

NEW SRB DATA SHOWING

DIURNAL VARIATIONS

GPCP RELEASES THREENEW PRECIPITATION

PRODUCTS

Shown above is the new 20+ year GPCPmonthly precipitation for 1979 to present.See examples on the back for the correspond-ing 5-day data set, along with an example ofthe new 1x1 degree daily product available for the last 3 years.Figures provided by NASA/GSFC. See http://orbit-net.nesdis.noaa.gov/arad/gpcp.

New results show monthly averaged diurnal range (max-min) of the surface net flux.Example above shortwave A, positive to surface, and longwave B, positive from surfacefor July 1986 for tropical/subtropical Atlantic and Mediterranean Basins. See Page 4.

WHAT'S NEW

• GLASS to exploit new sat-

ellite data and begincarbon intercomparisonstudy

• GCIP satellite productsbecome operational

• New WCRP Director wel-comed at GEWEX PhaseII Strategy Meeting

• 100 years of data show

teleconnection of precipi-tation between E. Asiaand N. America

• AMIP-II study to show im-pact of land surfaceschemes

August 20002

COMMENTARY

GEWEX CHANGING EMPHASISFOR PHASE II

Paul D. Try, DirectorInternational GEWEX Project Office

With the advent of the new series of earthsystem satellites (e.g., TERRA, TRMM, AQUA,ENVISAT, ADEOS II, Cloudsat and PICASSO),and with the success of the projects developedwithin Phase I, GEWEX is moving into Phase IIand building upon:

• new global descriptions of the earth’s envi-ronment

• upgraded model representations on which tobase predictions

• new local and regional descriptions of keyprocesses

• an increasing focus on water resource appli-cations

Our strategy for Phase I with its focus on theenergy and water cycle and its processes was simpleand straightforward: remain parameter focused andproduce the best possible descriptions of the ele-ments (and processes) of the energy and watercycle on a global basis; close the energy and waterbudgets on the continental scale; couple the hydrol-ogy/land/atmosphere at the mesoscale; model andpredict globally with high-resolution upgraded Nu-merical Weather Prediction models; and applyresults to water resources at the local scale.

As we move into Phase II, we need to modifythis strategy somewhat, and the GEWEX ScientificSteering Group Chairman and members, along withthe key GEWEX Panel and Project leaders, havebeen meeting to establish this modified strategy. Infollowing newsletter issues we will provide moredetails, but I would like to provide some insight intothe directions we are headed.

We will first be building upon the results fromour Phase I efforts and begin shifting our emphasistoward more analysis and diagnostics of the pro-cesses driving the energy and water cycle. We willbe working toward an integration of our global datainto a more complete description of the processesalong with developing the related model improve-ments necessary to enable improved representations

of these processes and their prediction. The em-phasis will be more focused on wet processes, linkagesto carbon, greater exploitation of satellite data, andexpanded efforts related to water resource applica-tions.

During this key transition period, as we awaitthe data from the series of new satellites, we willbe moving ahead with this modified strategy. Sev-eral of our current GEWEX activities are key tothese upcoming emphasis areas as we:

• provide for more intercomparison and analysisof our global data sets under the GEWEXRadiation Panel

• close the energy and water budgets and in-crease focus on water resource applicationswithin the Water and Energy Budget Study(WEBS) and Water Resources ApplicationsProject (WRAP) – both under the GEWEXHydrometeorology Panel, which is also leadingthe effort to integrate the benefits of the re-gional experiments and the new satellite datathrough the Coordinated Enhanced ObservingPeriod (CEOP) activities

• provide major advances in the development ofnew parameterization schemes and modelingfor hydrology, land surface and cloud sys-tems under the GEWEX Modeling and PredictionPanel along with a new focus on planetaryboundary layer representations within all scalesof models

Clearly many other GEWEX activities and projectswill also be contributing substantially to this transi-tion time and we hope to increase the participationof the international scientific community as we col-lectively join with the other WCRP projects (e.g.,CLIVAR, SPARC, CLIC and WGNE/WGCM) toincrease our knowledge of the earth system pro-cesses.

CHANGE AT GRDC

Dr. Thomas Maurer is the new head of theGlobal Runoff Data Centre (GRDC), Federal Instituteof Hydrology (BfG), Koblenz, Germany. Dr. Maureris a civil engineer with a background in hydraulicengineering, hydrology and numerical modeling. Hise-mail is: thomas.maurer@bafg.de; GRDC addressis: Global Data Runoff Centre (GRDC), P.O. Box200253, D-56002, Koblenz, Germany; Telephone:+49(0)261 1306 5224; Fax: +49 (0) 261 1306 5280.

3August 2000

CONTENTS

Commentary – GEWEX Changing Exmphasis for Phase II 2

Change at GRDC 2

New Director of WCRP 3

GLASS to Exploit New Satellite Data and Begin Carbon Intercomparison Study 3

SRB Release 2 Data Set 4

Analysis of AMIP II Models' Simulations of Land Surface Climates 5

GCIP Satellite Products Become Operational 8

GEWEX Activities at Open Scientific Meetings 9

Teleconnection of Precipitation Between Asia and Northwestern North American 9

Workshop/Meeting Summaries 12–15

GEW EX/W CRP Meetings Calendar 15

GLASS TO EXPLOITNEW SATELLITE DATAAND BEGIN CARBON

INTERCOMPARISON STUDY

At the first meeting of the GEWEX Global Land-Atmosphere System Study (GLASS) held July 19–21,2000 in Sydney, Australia, the science panel addedtwo new emphasis areas to their on-going off-lineand coupled Land Surface Scheme (LSS) modellingactivities — one specifically focused on the exploi-tation of the new satellite sensor data sets and theother focused on the coupled land/atmosphere as-pects of the carbon cycle. The first will involvethe production of satellite-sensed parameters by theLSSs for improved cross-validation, and the latteran off-line Project for Intercomparison of Land-surface Parameterization Schemes (PILPS) studyfocused on the carbon uptake and respiration. Moredetails will be provided in the GLASS implementa-tion Plan to be summarized in the next issue ofGEWEX News.

DAVID CARSONNEW DIRECTOR OF WCRP

Dr. David John Carson assumed responsibilityas Director of the Joint Planning Staff of the WorldClimate Research Programme in June 2000. Hesucceeds Professor Hartmut Grassl, who has re-turned to his director's post at Max-Planck Institutein Hamburg.

David began his re-search career in the UKMeteorological Office (theMet. Office) in 1969, fol-lowing his Ph.D from theDepartment of AppliedMathematics, University ofLiverpool. Early in hiscareer he conducted anddirected research on thestructure and evolution ofthe atmospheric boundarylayer, followed by researchon the development and

testing of atmospheric general circulation models,with particular emphasis on the representation ofphysical processes and devising methods for theapplication of numerical weather prediction modelsfor extended-range forecasting.

In 1982, he was appointed to Assistant Directorlevel within the Met Office, and led the BoundaryLayer Research Branch and later the Dynamical Cli-matology Branch. For 3 years (1987–1989), Davidwas seconded to the Natural Environment ResearchCouncil (NERC) as their first Programme Directorfor atmospheric sciences, to formulate and implementa NERC Strategy for Atmospheric Sciences.

On return to the Met. Office in January 1990,he became Director of Climate Research and, inthat capacity, the first Director of the Hadley Cen-tre for Climate Prediction and Research. Afteralmost 9 years at the Hadley Centre, he moved inNovember 1998 to become the Director of Numeri-cal Weather Prediction in the Met. Office.

David has been an active Fellow of the RoyalMeteorological Society since 1971, including beingits President in 1997–98. His Presidential addresseson Seasonal Forecasting and Climate Modelling:Achievements and Prospects have both been pub-lished in the Quarterly Journal of the RoyalMeteorological Society (in January 1998 and Janu-ary 1999, respectively).

August 20004

Monthly averaged SW diurnal cycles for Ber-muda in 1992 for SRB (3-hourly) and BSRN(hourly).

THE SRB PROJECT RELEASE 2 DATASET: AN UPDATE

P. W. Stackhouse, Jr.NASA Langley Research Center

S. K. Gupta, S. J. Cox,M. Chiacchio and J. C. Mikovitz

Analytical Services and Materials, Inc.

The WCRP/GEWEX Surface Radiation Bud-get (SRB) project at NASA was initiated, inassociation with the WCRP and later GEWEX, tofocus research on quantifying the radiative energyexchange at the Earth’s surface over time. NASAhas recently renewed support for GEWEX SRB toarchive a new data set, to provide for continueddevelopment and improvements, and to overlap withEarth Observing System era data sets. GEWEXSRB Release 2 (R2), a significant upgrade from theV1.1 WCRP SRB Shortwave (SW) 4-year data set(Whitlock et al., 1995), is now being prepared forprocessing and archival at the NASA Langley At-mospheric Sciences Data Center.

Among the many upgrades to algorithms andinput data sets, the most important are: the additionof longwave (LW) flux algorithms, the increase ofresolution from the 280 km x 280 km equal areagrid system to 1ox1o using the ISCCP DX pixeldata set (Rossow and Schiffer, 1999), and the useof reanalysis meteorology from a data assimilationproject. Column ozone is obtained from Total OzoneMapping Spectrometer (TOMS) data and a surfaceemissivity map is introduced (Wilber et al., 1999).This R2 data set will provide global SW and LWsurface and top-of-atmosphere radiative fluxes fora 12-year period (July 1983 – June 1995). Thefluxes will be produced at a variety of time resolu-tions including 3-hourly, daily, monthly and a monthlyaveraged 3-hourly product.

An example of R2 output showing the higherspatial and temporal resolution is shown on page 1.This figure gives the difference between the maxi-mum and minimum monthly averaged 3-hourly netSW and net LW surface fluxes in July 1986. Thedifferences represent the monthly averaged diurnalranges. The maps show how clouds, surface types,and boundary layer meteorology determine the rangeof net energy incident to and emitted from thesurface for this month.

The validation of data such as displayed onpage 1 remains a central part of SRB activity.Shown above is an example of the monthly aver-aged diurnal cycles of surface insolation from R2compared with hourly averaged Baseline SurfaceRadiation Network (BSRN) measurements from Ber-muda for the mid-seasonal months of 1992. Theresults indicate that the diurnal cycle is well cap-tured at this site, despite its island location.

More information on the SRB algorithms, pro-cessing status and data release will be made availableon the GEWEX SRB homepage:

http://srb-swlw.larc.nasa.gov/Pilot_homepage.html

References

Rossow, W.B. and R. Schiffer, 1999. Advances in understand-ing clouds from ISCCP. Bull. Amer. Meteor. Soc., 80, 2261-2287.

Whitlock, C.H., and co-authors, 1995. First global WCRPshortwave surface radiation budget dataset. Bull. Amer. Meteor.Soc., 76, 905-922.

Wilber, A. C., D. P. Kratz, S. K. Gupta, 1999. Surface emis-sivity maps for use in satellite retrievals of Longwave Radiation.NASA Technical Publication 1999-209362, 35 pp.

5August 2000

ANALYSIS OF AMIP II MODELS'SIMULATIONS OF

LAND SURFACE CLIMATES

Parviz Irannejad1, Ann Henderson-Sellers1,Tom Phillips2, and Kendal McGuffie3

1Australian Nuclear Science and Tech. Org.2PCMDI, Lawrence Livermore Natl Lab.

3Applied Physics, Univ. of Technology, Sydney

The first phase of the Atmospheric ModelIntercomparison Project (AMIP I) saw the partici-pation of some 30 modelling centres and nearly asmany diagnostic subprojects that analysed variousaspects of model simulations of climate in the de-cade 1979-1988. The Project for Intercomparisonof Land-surface Parameterization Schemes (PILPS)was responsible for AMIP Diagnostic Subproject12 on Land-surface Processes and Parameterizations.Subproject 12 (DSP12) analysed those AMIP simu-lations in which the associated land-surface schemes(LSS) were participating in PILPS off-line experi-ments. Subproject 12 performed its work in thecontext of several significant limitations: little globalland surface validation data; the limited set of model"standard output variables"; and the small range ofLSS complexity represented. In these circumstances,DSP12 carried out a "zero-order" evaluation in thesense that it identified problematical and/or unex-pected features in the simulations of various aspectsof the simulated land surface climates (Irannejad etal., 1995; Love et al., 1995; Qu and Henderson-Sellers, 1988).

In the current AMIP (Phase II), the ex-perimental design remains fundamentally thesame (i.e., commonly specified radiative forc-ing and ocean boundary conditions), but thesimulation period has been extended by 7 years(from 1979 to 1995) and several refinementsof the experimental protocol have been madeto attempt to address concerns expressed byland surface specialists in AMIP I. These in-clude a greater emphasis on adequateinitialization/spin-up of soil moisture stores; con-servation of continental surface energy and water;and a more extensive set of land surface vari-ables output. In addition, the spectrum of LSScomplexity included in AMIP II AGCMs isexpected to be broader than in AMIP I. Thus,DSP12 plans to continue its analysis of the relation-ship among land surface simulations, processes andparameterization schemes under these more auspi-

cious conditions (Phillips et al., 2000). This paperreports on the methodology to be applied in thisDiagnostic Subproject (Phillips et al., 1998). Theanalysis of the AMIP II land-surface simulation willbe performed globally and regionally. Analyses havebeen planned for GEWEX/Continental Scale Experi-ment (CSE) regions, shown below, and for differentclimate zones, defined by the de Martonne aridityindex: I = P / (T+10), where P is mean annualprecipitation in mm and T is mean air temperaturein degrees Centigrade. PILPS experiments have dem-onstrated that the bucket scheme behaves differentlyfrom complex land surface schemes (Chen et al.,1997). AMIP I showed that increased LSS com-plexity alters surface energy partitioning. Given thewider range of LSS employed in AMIP II, DSP12aims to analyse the surface energy and waterbudgets as a function of LSS complexity (Shaoand Henderson-Sellers, 1996).

An important difficulty in assessing the perfor-mance of climate models is the lack of high qualityglobal data sets. Until this data drought improves,for example, by future provision of the InternationalSatellite Land Surface Climatology Project (ISLSCP)Initiative II data sets, validation of the AMIP IImodels will necessarily rely heavily on possibly lessreliable model-derived estimates of land-surfacevariables such as those provided by various re-analyses. It must be emphasised that reanalysisdata contain any biases of the respective analysismodel and, therefore, should not be regarded asabsolute reality. Having this caveat in mind, model-derived estimates such NOAA's National Centersfor Environmental Prediction (NCEP), the Depart-ment of Energy (DOE), the National Center forAtmospheric Research (NCAR), and Variable Infil-tration Capacity (VIC) data, will be used as validation

GEWEX Continental-Scale Experiment (CSE) Regions

August 20006

data sets to try to account for any possible biases.NCEP-DOE is not fundamentally different fromNCEP-NCAR, but it is an updated global analysisthat fixes the known processing errors in NCEP-NCAR and uses an improved forecast model anddata assimilation system (Kanamitsu et al., 1999).The VIC data set consists of monthly (derived fromdaily) global terrestrial (excluding Greenland andAntarctica) data for the period 1979–1993. Thisdata set has been generated using the VIC landsurface scheme driven by forcing from station ob-servations of precipitation (where available) andmaximum and minimum surface air temperature andhumidity (Nijssen et al., 2000).

Some 30 AGCMs are participating in AMIP II.To date, simulations by five models have been qual-ity controlled and are available for analysis. In DSP12, all the reanalysis and model results will beinterpolated into T62 resolution for analysis. Here,the latent heat fluxes (LH) derived from NCEP-DOE, NCEP-NCAR and VIC are presented in orderto illustrate the analysis approaches to be employedin Diagnostic Subproject 12. NCEP-DOE is used asthe ‘control’ data set here. However, it should beemphasised that this selection is arbitrary and doesnot imply any superiority of NCEP-DOE over otherreanalyses.

The upper left panels of the figure on the op-posite page illustrate the distribution of the deviationsof 14-year (1980–1993) mean LH of the NCEP-NCAR and VIC data from the control (NCEP-DOE)over the continental surfaces. The mean latent heatflux of NCEP-NCAR generally agrees with that ofthe control, presumably because the two reanalysesare derived from the same origin. For instance, theNCEP-NCAR’s grid-averaged LH is within 10 W/

tica and Greenland) the LH from VIC is less thanthat from NCEP-DOE. In only 41 percent of theland grid points the mean LH estimated by VIC iswithin 10 W/m2 of that of the control, and in about25 percent of the grid points it is within 5 W/m2.

The lower panel on the opposite page com-pares the mean latent heat flux derived fromNCEP-NCAR and VIC for continental surfacesoverall and in different climate zones with fluxesfrom NCEP-DOE. Globally, NCEP-NCAR slightlyand VIC greatly underestimate mean latent heatflux compared to NCEP-DOE. However, the rela-tive differences are climate dependent, so that theglobal underestimation is mainly due to the under-estimation in wetter climates by VIC and in drierclimates by NCEP-NCAR. Furthermore, the grid-average LH relative to NCEP-DOE varies acrossthe climate zones. For instance, in 95 percent ofthe arid grid points the VIC’s mean LHs are within10 W/m2 of that of NCEP-DOE, but only 14 per-cent for the extremely humid grid points. Theinter-climate variability of mean LH is larger inNCEP-NCAR and much smaller in VIC comparedto NCEP-DOE.

Shown on the upper right panel, the spatio-temporal statistics of NCEP-NCAR and VICestimates of LH compared to NCEP-DOE for dif-ferent climate zones are plotted on a Taylor Diagram(Taylor 2000). The "Reference" is the land sur-face LH from NCEP-DOE for the period 1980–1993.In this polar plot, the radical distance is propor-tional to the spatio-temporal amplitude ratio, wherethe dotted quarter-circle denotes a perfect matchof the standard deviations of the evaluated and thecontrol. The angular dimension is scaled to beproportional to the cosine of the spatio-temporalpattern correlation. The coloured arrows show theaverage values for each de Martonne climate zone.The mean correlation coefficient of the availabledata is smaller in the arid zone and increases to-wards the wetter climates. There is no clearassociation between the magnitude of the meanamplitude ratio and the aridity index. Although themean latent heat flux of NCEP-NCAR agrees bet-ter with NCEP-DOE in most climates, its coefficientsof correlation are smaller and its amplitude ratiosare shifted further (inwards) from the unit quartercircle compared to those of VIC. The smaller-than-one amplitude ratios show that both

m2 of that of the control in about 67 percent of theland grid points and within 5 W/m2 of it in about 42percent of the land grid points. NCEP-NCAR tendsto underestimate LH in many arid and semi-aridsubtropical regions (Middle East, northern Mexicoand south-western United States, Australia); to over-estimate it both in very humid tropical regions (AmazonBasin, Indonesia, central Africa) and in cold regions(Greenland, Antarctica, Himalayas). In half of thegrid points the LH flux of NCEP-NCAR has posi-tive and in the other half negative biases relative toNCEP-DOE. VIC, on the other hand, greatly un-derestimates LH over almost all land surfaces, exceptfor relatively small areas in the Middle East, SouthAmerica and northern Africa. Globally in about 88percent of the land grid points (except for Antarc- (Continued on page 8)

7August 2000

Global distribution of the deviations (W/m2) of 14-yearmean latent heat flux of NCEP-NCAR and VIC reanaly-ses from NCEP-DOE over the continental surfaces.

Comparison of mean land-sur-face estimated latent heat flux(W/m2). The all LS shows theoverall LH over continents. Theclimate zones are arid, semi-arid,Mediterranean, sub-humid, hu-mid, very humid, extremely hu-mid, and polar. Due to lack ofVIC data over Antartica andGreenland, the values for NCEP-DOE have been calculated sepa-rately for comparison withNCEP-NCAR and VIC.

Shown in the structure of spatio-temporalvariability of NCEP-NCAR (circled) andVIC (not circled) of the reanalyses monthlymean latent heat flux for the perid 1980–1993 in different climate zones, with refer-ence to the corresponding NCEP-DOEreanalysis data set. (The colored arrowheads show the average (of NCEP-NCARand VIC) values for the de Martonne cli-mate zones.

August 20008

Simulations of Land-surface Climates(Continued from page 6)

NCEP-NCAR and VIC have smaller intra-climatevariability than NCEP-DOE.

Preliminary analysis so far has revealed that:

• Large-scale variations of LH are captured by allreanalyses considered. However, there are con-siderable differences among the three data sets.

• Compared to NCEP-DOE, the global mean LHover the land surfaces is underestimated greatlyby VIC, mainly due to lower LH in wetter cli-mates, and is underestimated slightly byNCEP-NCAR, due to underestimation in drierclimates.

• NCEP-NCAR has a larger and VIC has a smallerinter-climate variability of mean LH than NCEP-DOE. The intra-climate variability of both issmaller than that of NCEP-DOE.

• The spatio-temporal correlation coefficient ofestimated LH by NCEP-NCAR and VIC relativeto NCEP-DOE is small in drier climates andincreases towards wetter climates.

In summary, the AMIP DSP12 methodology forthe intercomparison of the land-surface simulationsas a function of LSS complexity and by evaluationagains pseudo-observations (reanalyses) is plannedto include: (a) Analysis of global and geographicalvariability; (b) Focused analysis for GEWEX-CSEregions and for areas where the inter-model differ-ences are large and/or simulations considerably differfrom reanalyses; and (c) Analysis in different cli-mate zones and across different latitudes.

References

Chen, T.H., and co-authors, 1997. Cabauw experimental re-sults from the Project for Intercomparison of Land-surfaceParameterization Schemes. J. Clim., 10(7), 1194–1215.

Love, P. K., A. Henderson-Sellers, and P. Irannejad, 1995.AMIP Diagnostic Subproject 12 (PILPS Phase 3): Land surfaceprocesses. Proceedings of the First International AMIP Scien-tific Conference, Monterey, California, USA, 15–19 May 1995,WCRP-92, WMO/TD-No. 732.

Irannejad, P., A. Henderson-Sellers, Y. Shao, and P.K. Love,1995. Comparison of AMIP and PILPS off- line land surfacesimulation. Proceedings of the First International AMIP Sci-entific Conference, Monterey, California, USA, 15–19 May1995, WCRP-92, WMO/TD-No. 732, 465-470.

Kanamitsu, M., W. Ebisuzaki, J. Woolen, J. Potter, and M.Fiorino, 1999. Overview of NCEP/DOE Reanalysis-2. TheSecond International Conference on Reanalyses, Reading, UK.Accessible online at http://wesley.wwb.noaa.gov/reanalysis2/kana/Overview.htm.

Nijssen, B., R. Schnur, and D.P. Lettenmaier, 2000. Globalretrospective estimation of soil moisture using the VIC landsurface model, 1980–1993. Accepted J. Climate.

Phillips, T.J., A. Henderson-Sellers, P. Irannejad, K. McGuffie,and H. Zhang, 2000. On validation and diagnosis of land-surface climate simulations. Climate Change Newsletter, 12(1),3–5.

Phillips, T.J., A. Henderson-Sellers, A. Hahman, and A.J. Pit-man, 1998. AMIP II diagnostic subproject 12: Landsurfaceprocesses and parameterizations (a joint AMIP/PILPS project).Accessible online at http://www.pcmdi.llnl.gov/pilps3/proposal/.

Qu, W.Q. and A. Henderson-Sellers, 1998. Comparing thescatter in PILPS off-line experiments with those in AMIP Icoupled experiments. Global Planet. Change, 19, 209–224.

Taylor, K.E. (2000). Summarizing multiple aspects of modelperformance in a single diagram. J. Geophys. Res. (submitted).

Shao, Y., and A. Henderson-Sellers, 1996. Modeling soil mois-ture: PILPS Phase 2(b). J. Geophys. Res., 101, 7227-7250.

GCIP SATELLITE PRODUCTSBECOME OPERATIONAL

The National Environmental Satellite Data andInformation Service (NESDIS) of NOAA recentlyapproved a set of products developed for GCIP.The quantities made operational are insolation, photo-synthetically active radiation, and surface temperature.These products were developed and used to validateand force the land surface components of regionalnumerical weather prediction models. The cloudcover, cloud fraction, cloud and surface brightnessesderived from geostationary satellite data are used toestimate incident solar radiation (insolation) at hourlyintervals and at a resolution of 0.5o latitude/longituderesolution. For clear scenes, a surface (skin) tem-perature is estimated using split-window retrievalfrom the 11 and 12 µm bands of the imager. Thefirst use of the insolation and surface temperaturewas to validate the radiation and surface physicsschemes of regional forecast models. The model soilmoisture is expected to be greatly improved from theuse of these products.

These products may be viewed at: http://orbit-net.nesdis.noaa.gov/goes/gcip/ . They are beingarchived at the University of Maryland: http://metosrv2.umd.edu/~srb/gcip/gcipsrb.htm.

9August 2000

TELECONNECTION OFPRECIPITATION BETWEEN EAST ASIA

AND NORTHWESTERNNORTH AMERICA

G. W. K. Moore1, Gerald Holdsworth2,and Keith Alverson3

1University of Toronto, Canada2Arctic Institute of North America, Canada

3PAGES Intl Project Office, Switzerland

Mount Logan, elevation 5,957 m, is the highestmountain in Canada and only 160 m shorter thanDenali-Mount McKinley. It is situated 100 kmfrom the Gulf of Alaska in a region that has sup-ported near-continuous human settlement for over10,000 years. Yet, there is no evidence that it wasnamed or sighted by either aboriginals or Europeansprior to 1890. Notwithstanding our ignorance of itsexistence, the mountain has been accumulating, inits snow and ice, climatic information over a periodextending back to the 17th century and perhapsearlier. The mountain’s strategic location makesthis information especially important. It is situ-ated at the end of the major North Pacific stormtrack along the main atmospheric pathway by whichwater vapor enters the Mackenzie River Basin(Smirnov and Moore, 1999). In addition, it is inthe center of the region that experiences oneof the largest extra-tropical responses to ENSO(Horel and Wallace, 1981). Its extreme heightallows it to sample the mid-tropspheric flowwhere these processes have their largest am-plitudes. In this paper, we report on some of thefindings obtained from the analysis of ice coresobtained at a height of 5,340 m on Mount Logan(Holdsworth et al.,1992).

Various stratigraphic techniques were applied todate the core (Holdsworth et al., 1992), resulting ina time series of annual net snow accumulationextending from 1736 to 1985. It is important torecognize that total annual precipitation cannot beretrieved from the ice core data. However, underthe assumption that deposition and scour at the sitehave been approximately uniform over time, thedata, nevertheless, contain useful climatic informa-tion. For example, its power spectrum has statisticallysignificant power at the ENSO and decadal periods(Holdsworth et al.,1992).

The motivation for this paper was to determinethe regions in which the annual precipitation is

GEWEX ACTIVITIES AT OPENSCIENTIFIC MEETINGS

Reports on GEWEX results are increasing inrefereed literature and at major scientific confer-ences, such as the European Geophysical Society(EGS) XXV Assembly, April 2000, in Nice, France.At the EGS meeting there was a GEWEX sessionthat focused on water cycles over large and me-dium-sized drainage areas as well as a number ofother presentations related to GEWEX in hydrologyand ocean-atmosphere sessions. At the recent meetingof the American Geophysical Union (AGU), 30 May–2 June 2000, sessions were held throughout theweek reporting on GEWEX research in hydrology,land-surface processes, atmospheric modeling, anddiscussions on water resource and hydrology policy.

One example of GEWEX sessions at scientificmeetings is summarized on page 14. Also, at thesame AGU Meeting was a session titled "Advancesin GEWEX Continental-scale International Project(GCIP) Research," an update on research reportedin the special issues of the Journal of Geophysi-cal Research (Vol. 104, No. D10, 1999) on GCIP.The focus of this AGU GCIP session was on sea-sonal and interannual variability in moisture sources,precipation (including two papers on snow), soilwetness, and water resource management. Fromthe papers in the GCIP session, it was evident thatGCIP investigators have continued to make goodprogress in developing their understanding of re-gional water and energy budget components. SeveralGCIP principals were also involved in a specialinterdisciplinary Union Session on linking the hydro-logical sciences to water resource policy andapplications. The large audience heard how GEWEX,the GCIP follow-on, called the GEWEX AmericanPrediction Project (GAPP), and the US Global WaterCycle Initiative will make important contributions tosociety's needs during the next decade. It was clearthat expectations are growing both within and out-side the GCIP community for a strong GAPP scienceprogram with substantive links to water resourceapplications.

Another example of GEWEX activities at majormeetings is the forthcoming American MeterologicalSociety Meeting (14–19 January 2001), where thereare sessions reporting scientific results on aerosolresearch (GEWEX Global Aerosol ClimatologyProject) and the impact of precipitation extremes(GEWEX Global Precipitation Climatology Project).Also, at the Fall AGU meeting, cold season landprocesses research will be presented.

August 200010

correlated with the Mount Logan time series. Tothis end, we made use of a gridded global precipi-tation data set derived from the Global HistoricalClimatology Network (GHCN) covering the periodfrom 1851 to 1985 (Vose et al., 1992; Baker et al.,1995). The figure above shows the Pearson cross-correlation coefficient of the gridded GHCN annualprecipitation data with the Mount Logan time se-ries. An overlap of at least 50 years was requiredfor inclusion in the analysis. Only those locationswhere the cross correlation is statistically signifi-cant at the 99 percent confidence interval are shown.The figure above clearly shows a number oflocations (shown in red) where there is a sta-tistically significant positive correlation with theMount Logan time series. These locations(circled) include the Mackenzie River Basin ofNorthern Canada, the North Slope of Alaska,Japan and the Sichuan region of China. Astatistically significant anti-correlation exists with alocation in Siberia (shown in blue). Japan and theMackenzie River Basin are of particular interest asthey are regions where there is clustering of loca-tions with statistically significant correlations. Theaverage length of the overlap for the regions inwhich there was a statistically significant cross-correlation was 101 years. No significant correlationof either sign was identified with neighboring loca-tions. This result holds even at significance levelsas low as 90 percent.

The absence of any correlation with nearbylocations is consistent with surface snow pit samplesfrom Mount Logan (Holdsworth et al., 1991). Thesedata show a discontinuity in the isotopic ratio ofoxygen and hydrogen with elevation that suggests adifferent source region for the precipitation thatfalls at low elevations as compared to that at higherelevations. This finding is supported by the meteo-rology of the region. Extra-tropical cyclones in theGulf of Alaska are responsible for much of theprecipitation that falls on Mount Logan and in theMackenzie River Basin, the Mackenzie GEWEXStudy (MAGS) region, to the east (Smirnov andMoore, 1999). Shown on the next page is anexample of one such cyclone and the water vaportransport associated with it is illustrated in the sat-ellite imagery. The transport at 925 hPa clearlyshows that the low-level circulation associated withthe system advects moisture from the Bering Seainto the Gulf of Alaska. The moisture at this levelis intercepted by the topography. At 700 hPa, onecan see the inflow of moisture that intercepts MountLogan and which enters the Mackenzie River Ba-sin. At this height, the moisture is associated withthe system’s frontal zone and as such has beenlifted to this level along its warm conveyor beltfrom a source region to the southwest. Smirnovand Moore (2000) argue that this source region isin the subtropical north Pacific.

Spatial cross correlation of the annual meansea-level field from the NCEP reanalysis withthe Mount Logan (indicated by the asterisk) netannual snow accumulation time series (1948–1985). Only those locations where the crosscorrelation is statistically significant at the 95percent confidence level are shown.

Spatial cross-correlation of gridded annual pre-cipitation time series with Mount Logan timeseries. Japan (A) and McKenzie River (B) arealocations where the cross correlation is positiveand statistically significant at the 99 percentconfidence level (indicated in red).

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Water vapor transport at 925 hPa (upper) and700 hPa (lower) at 18 GMT on September 24,1994 as diagnosed from the ECMWF objec-tively analyzed fields. The fields are superim-posed on an infrared image from a pass of theNOAA 12 polar orbiting satellite that occurredat 17:51 GMT on the same day. The locationof Mount Logan (60o37'N, 140o31'W) is indi-cated by the large arrows.

For the remainder of this paper, we will focusour attention on elucidating the meteorological pro-cesses responsible for the correlation that existswith annual precipitation in Japan and the MackenzieRiver Basin. They were identified in the firstfigure shown as being regions where there was aclustering of grid points with a high degree of cor-relation with the Mount Logan time series. Thecorrelation with the Mackenzie River Basin (MAGS)region is relatively easy to understand. As dis-cussed above, extra-tropical cyclones are responsiblefor much of the moisture that is transported intothe basin (Smirnov and Moore, 1999; 2000). Thedominant route for this transport is from the south-west and as such is intercepted by Mount Logan.

It, therefore, seems reasonable, given the commonmoisture source, that there should exist a high de-gree of correlation between precipitation in the basinand the snow accumulation on Mount Logan. Nosuch correlation exists with coastal stations nearMount Logan.

The correlation with precipitation in Japan, at adistance of some 6,000 km, is at first glance re-markable. The lower figure on the opposite pageshows the Pearson cross correlation coefficient ofthe annually averaged sea-level pressure field fromthe NCEP/NCAR reanalysis with the Mount Logandata for the period 1948–1985. The field has re-gions of negative (blue) correlation on the westernand eastern boundaries of the North Pacific Ocean.It follows that above average snow accumulationon Mount Logan is associated with lower than av-erage sea-level pressures and hence enhanced cyclonicactivity in the Gulf of Alaska and along the coastof Japan or vice versa. Such a pattern is consis-tent with the observed correlation of precipitation inJapan with the Mount Logan data. The mechanismthat leads to this teleconnection in the sea-levelpressure field has not yet been identified. Spectraland coherence analysis indicates a strong El NiñoSouthern Oscillation (ENSO) signal in the MountLogan time series (Holdsworth et al.,1992; Mooreet al., 2000). Recently, it has been shown thatprecipitation in east Asia is also modified by ENSO(Wang et al., 2000). It is, therefore, possible thatthe observed teleconnection may be an indirectone due to ENSO. Alternatively, Lau and Wang(2000) have identified a "Pan-Pacific" wave-trainwith centers of action off east Asia and westernNorth America. Still unresolved is the relationshipof this mode with ENSO.

The present Mount Logan time series is nearly300 years in length and there is the potential withnew drilling to extend it back further. The longrange and robust correlation of precipitation withthe time series that has been identified is evidenceof its usefulness as a source of climate information.A key to unlocking this understanding is improvedknowledge of:

• the impact of teleconnections and ENSO onPacific Ocean storm tracks

• the structure of extra-tropical cyclones in theGulf of Alaska/Mount Logan region

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• the sources of and pathways through whichmoisture is transported by these weather sys-tems

• the interaction of these cyclones with the to-pography in northwestern North America

Such research will add to our understanding ofthe Mount Logan ice core as well as the physicalprocesses responsible for atmospheric teleconnections.The proposed Coordinated Enhanced Observ-ing Period (CEOP) with its links to variousGEWEX programs and regional experimentswould be an ideal vehicle to study the linkagesidentified in this paper.

Acknowledgments: NCEP reanalysis data pro-vided by the NOAA-CIRES Climate DiagnosticsCenter, Boulder, Colorado, USA. GHCN dataprovided by the NOAA National Climate DataCenter, Asheville, North Carolina, USA.

References

Baker, C.B., J.K. Eischeid, T.R. Karl, and H.F. Diaz, 1995.The quality control of long-term climatological data usingobjective data analysis. Preprints of AMS Ninth Confer-ence on Applied Climatology. (available atwww.ncdc.noaa.gov/gcps/papers/qc1/qc.html)

Holdsworth, G., S. Fogarasi, and H.R. Krouse, 1991. Varia-tion of the stable isotopes of water with altitude in theSaint Elias Mountains of Canada. J. Geophys. Res., 96(D4), 7483–7494.

Holdsworth, G., H.R. Krouse, and M. Nosal, 1992. Ice coreclimate signals from Mount Logan Yukon 1700–1987 inClimate Since A.D. 1500, ed by Bradley R.S. and Jones,P.D. Routledge UK.

Horel, J.D., and J.M. Wallace, 1981. Planetary scale atmo-spheric phenomena associated with the Southern Oscillation.Mon. Wea. Rev. 109, 813–829.

Lau, K.M., and H. Wang, 2000. Remote forcing of sum-mertime U.S. Draughts and floods by the Asian monsoon.GEWEX News 10:2 pg 5–6.

Moore, G.W.K., G. Holdsworth, and K. Alverson, 2000.Climate variability since 1736 as expressed in an ice corefrom the Saint Elias mountain range in northwestern NorthAmerica, manuscript in preparation.

Smirnov,V.V., and G.W.K. Moore, 1999. Spatial and Tem-poral Structure of Atmospheric Water Vapour Transportin the Mackenzie River Basin, J. Climate. 12,681–696.

Smirnov,V.V., and G.W.K. Moore, 2000. Short-term andSeasonal Variations of the Atmospheric Water Vapor Trans-port through the Mackenzie River Basin, manuscriptsubmitted to J. Hydromet.

WORKSHOP/MEETING SUMMARIES

WORKSHOP ON SOIL MOISTUREFOR HYDROMETEOROLOGICAL AND

HYDROCLIMATOLOGICALAPPLICATIONS

16–19 May 2000Norman, Oklahoma

John A. LeeseGCIP Project Office

The GEWEX Scientific Steering Group, notingthe rapid progress in modeling land surface pro-cesses and developing a coupled land-hydrology/atmosphere model for weather and climate predic-tion, recommended holding a workshop on soil moisture.In parallel with this GEWEX effort on soil moisture,the International Geosphere Biosphere Programme/Biospheric Aspects of the Hydrologic Cycle (IGBP/BAHC) was developing plans to hold a workshop onmodeling root water uptake in hydrological and cli-mate models. Discussions among scientists led tothe joining of efforts for two workshops.

The first workshop was held from 30 Septemberto 2 October 1999 at Gif-sur-Yvette, France. Theprincipal objective was to develop a research strat-egy for the next 3–5 years, aiming at a systematicdescription of root functioning, rooting depth, androot distribution for modeling root water uptake atregional to global scales. A summary report on thisworkshop was published in BAHC News, No. 7 inMay 2000.

This is a brief summary on the second work-shop held at the University of Oklahoma in NormanOklahoma. The full meeting report will be publishedas International GEWEX Project Office PublicationSeries No. 34 in September 2000.

Vose, R.S., R.L. Schmoyer, P.M. Steurer, T.C. Peterson, R.Heim, T.R. Karl, and J.K. Eischeid, 1992. The Global His-torical Climatology Network: Long-term monthly temperature,precipitation,sea level pressure, and station pressure data.NDP-041. Carbon Dioxide Information Analysis Center,Oak Ridge National Laboratory, Oak Ridge,Tennessee.

Wang, B., R. Wu, and X. Fu, 2000. Pacific-east Asianteleconnections: How does ENSO affect east Asian Cli-mate? J. Climate. 13,1517–1525.

13August 2000

In considering the progress in land surfaces pro-cesses and modeling, which entails the complex aspectsof soil moisture, it was decided that the Workshopneeded to focus on an overall objective designedto develop a strategic plan for the next 5 yearsin soil moisture monitoring, analysis and predic-tion for hydrometeorological and hydroclimatologicalapplications, which: (a) identifies and recommendspriorities for research; (b) demonstrates the scien-tific and technical feasibility of implementing a globalsystem through one or more pilot projects or anevolutionary series of pilot projects; and (c) contrib-utes to the design of a global system which could beoperational by the end of this decade.

Soil moisture is an environmental descriptor thatintegrates much of the land surface hydrology and isthe interface between the solid earth surface and theatmosphere. As important as this seems to ourunderstanding of hydrology, the related ecosystemdynamics, and biogeochemical cycles, it is a de-scriptor that has not had widespread application inthe modeling of these processes. The main reasonis it is a very difficult variable to measure, not at apoint in time, but on a consistent and spatially com-prehensive basis. The large spatial and temporalvariability that soil moisture exhibits in the naturalenvironment is precisely the characteristic that makesit difficult to measure and use in earth science ap-plications.

There have been a number of field experimentsduring the decade of the 1990s. Noteworthy is aseries of field experiments in the state of Oklahomain the USA in 1992, 1997, 1999 and plans for an-other in 2001. The focus of the first three fieldexperiments was on the algorithm development forderiving soil moisture estimates from microwave data.The main elements of a planned 2001 experiment arevalidation of the Advanced Microwave Scanning Ra-diometer (AMSR) brightness temperature and soilmoisture retrievals, extension of instrument observa-tions and algorithms to more challenging vegetationconditions, and the evaluation of new instrumenttechnologies for soil moisture remote sensing. Twoversions of the AMSR instrument will be launched inthe 2001–2002 time frame on the AQUA and ADEOS-II platforms. A primary science objective is thestudy of the interaction of soil moisture and theatmospheric boundary layer.

A plenary discussion was held to achieve a com-mon understanding about the characteristics of aglobal system for soil moisture monitoring, analysis

and prediction. The initial characteristics of such asystem are to provide measurements and/or esti-mates of volumetric soil water content on at least adaily basis at a 50-km resolution and at verticalresolutions consistent with vegetative rooting depthswithin the resolution grid. The participants agreedthat assessments of the utility of soil moisture dataproducts at 25 and 10 km horizontal resolution wouldalso be helpful as inputs to the design of a futureglobal operational system.

It was generally agreed that a soil moisturemonitoring system will be model based with the insitu and remotely sensed measurements used prima-rily for validation and evaluation of the model-derivedfields. One can consider a coupled land-hydrology/atmosphere model as the basis for producing soilmoisture analysis and prediction data products.However, the current weakness in General Circula-tion Models (GCM) in accurately predicting precipitationcould necessitate the use of uncoupled models toproduce these data products. The Workshop fo-cused on applications in agriculture, hydrology andmeteorology.

Based on considerations of the workshop presen-tations, it was agreed that a global system for soilmoisture is needed and, furthermore, a rudimentarysystem could be implemented on an experimentalbasis with tools currently available. This system shouldhave the ability to monitor soil moisture on a dailybasis, should provide data sets and analyses for di-agnostic studies and applications and should providepredictions and, possibly, future scenarios of soilmoisture conditions. However, many future im-provements would be essential to make such a systemsuccessful and operational. The priority researchtopics within the areas of soil moisture monitoring,analysis and prediction and applications will appearin the IGPO report mentioned above. This reportwill address a specific recommendation on develop-ing a global monitoring system for soil moisture,providing a strategy for developing (in situ and re-mote) instruments, identifying deficiencies in modelsand producing long-term soil moisture data sets foruse in climatological studies and applications.

This Workshop succeeded in bringing togetherthe scientists working on different aspects of soilmoisture monitoring, analysis and prediction. Theresults can provide a solid foundation for the designand implementation of a global system for hydro-meteorological and hydroclimatological applications.

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support the GEWEX ISLSCP Initiative II data set.Istuam Laszlo, University of Maryland, discussed anew research version of the shortwave algorithmthat uses the vertical structure of the atmosphereincluding multiple layers of clouds.

Thomas Vonder Haar, Colorado State University,discussed how water vapor feedback processes withinthe earth’s climate system require new scientificobservations, analyses and modeling experiments. TheGEWEX Global Water Vapor Project (GVaP) is aninternational collaboration to address the role of watervapor in variations of the water and energy cycle.

B. Sohn, University of Seoul, Korea, showedhow indirect calculation methods in which horizontaldivergence of water vapor is balanced by the evapo-ration minus precipitation and thus transports couldbe calculated from remotely sensed products andcompared to transports from numerical weather pre-diction analyses. Clouds are also critical componentsaffecting the atmospheric hydrologic cycle, DavidStarr, and Ruei-Fong Lin, NASA Goddard SpaceFlight Center (GSFC), gave presentations on theGEWEX Cloud Systems Study (GCSS) systematiccomparison and evaluation of cirrus cloud models.

Robert Adler, NASA/GSFC, discussed climato-logical projects of the Global Precipitation ClimatologyProject (GPCP). These data are now being used tovalidate general circulation models. George Huffman,NASA/GSFC, discussed a new 1-degree daily GPCPprecipitation data set (see page 1). Scott Curtis alsoshowed how GPCP data could be used to studyintraseasonal fluctuations over the tropics. PeteRobertson, NASA Marshall Space Flight Center, thendiscussed some new results of precipitation estima-tion from satellites and how some of the variationswere different from current GPCP data sets. BrianSoden, NOAA Geophysical Fluid Dynamics Labora-tory, suggested that global climate models, forcedwith observed sea-surface temperatures (SST) accu-rately reproduce the observed tropospheric temperature,water vapor and outgoing longwave radiation changes.However, the predicted variations in tropical-meanprecipitation rates are substantially smaller than ob-served.

Rick Lawford, GCIP Project Office, introducedthe U.S. GEWEX Continental-scale International Project(GCIP) and its transition to GEWEX America Pre-diction Project (GAPP). Rick Lawford noted thatspecific GCIP successes included a better under-standing of land processes and heterogeneity, more

U.S. GEWEX RESEARCH PROGRESSPRESENTED AT THE

AGU SPRING MEETING

John RoadsScripps Institution of Oceanography

30 May – 3 June, 2000Washington, DC

The National Research Council’s (NRC) Globaland Water Cycle Experiment (GEWEX) Panel heldspecial sessions on GEWEX at the Spring AmericanGeophysical Union meeting in Washington, DC, on31 May and 1 June. The main purpose of thesesessions, chaired by John Roads, Chairman of NRCGEWEX Panel, and Peter Schultz, NRC, was toreview U.S. contributions to GEWEX. Presentationswere made on research pertaining to the earth’sradiation balance, hydrologic cycle, and modeling andobservations of the coupled land-atmosphere system.

Paul Try, International GEWEX Project Office,stated that the goal of the GEWEX Program is toreproduce and predict, by means of suitable models,the variations of the global hydrological regime, itsimpact on atmospheric and surface dynamics, varia-tions in regional hydrological processes and waterresources and their response to changes in the envi-ronment. (See Commentary on page 2 of this issuefor GEWEX plans). Nancy Ritchey, NASA LangleyResearch Center (LaRC), presented a poster on anumber of GEWEX data sets available from the LaRCAtmospheric Science Data Center, including prod-ucts from the Surface Radiation Budget (SRB) Project,International Satellite Cloud Climatology Project(ISCCP), NASA Water Vapor Project (NVAP), theInternational Satellite Land-Surface Climatology Project(ISLSCP) Initiative I, and the Earth Radiation BudgetExperiment.

Joyce Penner, University of Michigan, discussedthe Global Aerosol Climatology Project (GACP), whichaims to build an accurate understanding of the abun-dance of aerosols by comparison of satellite, as wellas ground-based observations with models. PaulStackhouse, NASA Langley Research Center, dis-cussed the importance of accurately determining thesurface radiation budget at the earth’s surface. TheSRB Project aims to use a newly developed process-ing and analysis system to supply long-term accuratesurface and top-of-atmosphere (TOA) radiative bud-get quantities to meet user research and industrialneeds, the most pressing of which is the need to

15August 2000

accurate water budget estimates, development ofadvanced land-surface schemes and the incorpora-tion of these schemes into prediction systems, newdata sets using remotely sensed data and new in situmeasurement systems, and advanced data assimila-tion systems. Specific aspects were discussed inthe companion AGU special session on GCIP.

Chris Milly, Geophysical Fluid Dynamics Labora-tory, discussed how GEWEX had contributed to anincreased focus on the land surface and how theseinvestigations were being facilitated by products fromthe SRB data set, the ISLSCP Initiative I CD-ROM,the GRDC database, and by the Project forIntercomparison of Land-Surface ParameterizationSchemes (PILPS).

Eric Wood, Princeton University, discussedmacroscale hydrological models, which predict fluxesand runoff at continent and subcontinent scales. HidekiKanamaru, Boston University, discussed another es-timate of runoff, from net top-of-atmosphere radiationvia the coupled water and energy balance of theatmosphere. John Roads discussed surface waterand energy budgets over the continental United States.Vasubandhu Misra, Center for Ocean-Land-Atmosphere(COLA) Studies, discussed similar budget terms forBrazil. Oreste Realle, COLA, discussed how theimpact of land variability on climate variability canbe made and compared to the role of ocean variabil-ity in general circulation models. Kaye Brubaker,University of Maryland, showed how back trajectoryanalysis could be used to analyze evaporative sourcesfor moisture in the Mississippi River Basin.

27–29 September 2000—ERB2000 CONFERENCE ON MONI-TORING AND MODELLING CATCHMENT WATERQUANTITY AND QUALITY, Ghent, Belgium.

11–13 October 2000—THIRD MEETING OF THE GLOBALAEROSOL CLIMATOLOGY PROJECT (GACP), Lanham-Seabrook, Maryland, USA.

16–20 October 2000—WORKING GROUP ON NUMERICALEXPERIMENTATION (WGNE)/BUREAU OF METEOROL-OGY RESEARCH CENTRE (BMRC) WORKSHOP ONSYSTEMATIC ERRORS, Melbourne, Australia. The work-shop web site is: http://www.bom.gov.au/bmrc/admin/syserr.html

23–27 October 2000—GEWEX MODELING AND PREDIC-TION PANEL (GMPP)/WORKING GROUP ON NUMERICALEXPERIMENTATION (WGNE), Melbourne, Australia.

6–10 November 2000—SECOND GENERAL ASSEMBLY OFSPARC: STRATOSPHERIC PROCESSES AND THEIR ROLEIN CLIMATE, Mar del Plata, Argentina.

15–17 November 2000—ISLSCP INITIATIVE II MEETING,NASA/GSFC, Greenbelt, Maryland, USA.

15–17 November 2000—6TH MAGS SCIENCE WORKSHOP,Saskatoon, Canada.

29 November – 1 December 2000—GEWEX CLOUD SYS-TEM STUDY (GCSS) SCIENCE PANEL MEETING, Tokyo,Japan.

11–13 December 2000—INTERNATIONAL SATELLITECLOUD CLIMATOLOGY PROJECT (ISCCP) WORKINGGROUP ON DATA MANAGEMENT (WGDM) AND SCI-ENCE ADVISORY TEAM MEETING, NASA Goddard Institutefor Space Studies, New York City, NY, USA.

15–19 December 2000—AMERICAN GEOPHYSICAL UNIONFALL MEETING, San Francisco, California, USA. Land-sur-face and cold season processes to be addressed. For information:www.agu.org/meetings.

14–19 January 2001—81ST AMERICAN METEOROLOGI-CAL SOCIETY MEETING, Albuquerque, New Mexico, USA.Special symposia include: Global Aerosol Climatology; 12thSymposium on Global Change Studies and 5th Symposium onIntegrated Observing Systems. For information consult:www.ammetsoc.org/meetings.

29 January – 2 February 2001—GEWEX SCIENTIFIC STEER-ING GROUP MEETING, Barcelona, Spain.

19–24 March 2001—WCRP JOINT SCIENTIFIC COMMIT-TEE MEETING, Boulder, Colorado, USA.

GEWEX/WCRP MEETINGSCALENDAR

For calendar updates, see the GEWEX Web site:http://www.gewex.com

11–15 September 2000—GEWEX HYDROMETEOROLOGYPANEL, Angra dos Reis, Brazil.

GEWEX NEWSPublished by the International GEWEX Project Office (IGPO)

Dr. Paul D. Try, DirectorEditor: Dr. Paul F. TwitchellMail: International GEWEX Project Office1010 Wayne Avenue, Suite 450Silver Spring, MD 20910, USA

WWW Site: http://www.gewex.com

Assistant Editor: Dawn P. ErlichTel: (301) 565-8345Fax: (301) 565-8279E-mail: gewex@cais.com

August 200016

GPCP DAILY 1X1 DEGREE IMAGES OF HURRICANE MITCH

The above example of the new GPCP 1x1 degree daily preciptation product (available from 1997 to present) for 26October 1998, illustrates the global coverage for 26 October 1998 and daily changes in the precipitation associated withHurricane Mitch from 24–30 October 1998. The black X's denote Mitch's 12Z daily position. (G. J. Huffman et al.,2000; Global Precipitation at 1-Degree Daily Resolution from Multi-satellite Observations; submitted to J. Hydromet.)

Time-longitude plots of es-timated precipitationanomalies during June–December 1996 in mm/dayunits. Dashed lines on theGPCP pentad analysis (leftpanel) indicate periods ofincreased convective pre-cipitation associated withMadden-Julian Oscillationactivity. Such oscillationsare not apparent in themonthly analysis (rightpanel). Attribution: Dr.Pingping Xie, Climate Pre-diction Center/NCEP/NWS.

NEW GPCP PENTAD (5-DAY) PRODUCT SHOWS MJO