NASA/TMm2000-209891, Vol. 54

Technical Report Series on the

Boreal Ecosystem-Atmosphere Study (BOREAS)

Forrest G. Hall and Jaime Nickeson, Editors

Volume 54

BOREAS RSS-8 BIOME-BGC Model

Simulations at Tower Flux Sites in 1994

John Kimball

University of Montana, Missoula, Montana

National Aeronautics and

Space Administration

Goddard Space Flight Center

Greenbelt, Maryland 20771

August 2000

https://ntrs.nasa.gov/search.jsp?R=20010022093 2018-05-15T06:38:13+00:00Z
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NASA/TMm2000-209891, Vol. 54

Technical Report Series on the

Boreal Ecosystem-Atmosphere Study (BOREAS)

Forrest G. Hall and Jaime Nickeson, Editors

Volume 54

BOREAS RSS-8 BIOME-BGC Model

Simulations at Tower Flux Sites in 1994

John Kimball

University of Montana, Missoula, Montana

National Aeronautics and

Space Administration

Goddard Space Flight Center

Greenbelt, Maryland 20771

August 2000
NASA Center for AeroSpace Information

7121 Standard Drive

Hanover, MD 21076-1320

Price Code: A17

Available from:

National Technical Information Service

5285 Port Royal Road

Springfield, VA 22161

Price Code: A10
BOREAS RSS-8 BIOME-BGC Model Simulations at Tower Flux Sites in

1994

John S. Kimball

Summary

BIOME-BGC is a general ecosystem process model designed to simulate biogeochemical and

hydrologic processes across multiple scales (Running and Hunt, 1993). In this investigation,

BIOME-BGC was used to estimate daily water and carbon budgets for the BOREAS tower flux sites

for 1994. Carbon variables estimated by the model include gross primary production (i.e., net

photosynthesis), maintenance and heterotrophic respiration, net primary production, and net ecosystem

carbon exchange. Hydrologic variables estimated by the model include snowcover, evaporation,

transpiration, evapotranspiration, soil moisture, and outflow. The information provided by the

investigation includes input initialization and model output files for various sites in tabular ASCII

format.

Table of Contents

1) Model Overview

2) Investigator(s)

3) Model Theory

4) Equipment

5) Data Acquisition Methods

6) Observations

7) Data Description

8) Data Organization

9) Data Manipulations

10) Errors

11) Notes

12) Application of the Model

13) Future Modifications and Plans

14) Software

15) Data Access

16) Output Products and Availability

17) References

18) Glossary of Terms

19) List of Acronyms

20) Document Information

1. Model Overview

1.1 Model Identification

BOREAS RSS-08 BIOME-BGC Model Simulations at Tower Flux Sites in 1994

1.2 Model Introduction

BIOME-BGC simulates biogeochemical and hydrologic processes across multiple biomes based on

the logic that differences in process rates between biomes are primarily a function of climate and

general life-form characteristics. The carbon balance portion of BIOME-BGC utilizes daily

meteorological data in conjunction with general stand and soil information to predict net

photosynthesis, growth, maintenance, and heterotrophic respiration at a daily time-step. BIOME-BGC

is general in the sense that the surface is represented by singular, homogeneous canopy and soil layers.

Page 1
DetaileddescriptionsofBIOME-BGClogicaregivenby RunningandCoughlan(1988)andRunning

andHunt(1993).A descriptionof thecomponentsof themodelrelatingto thepredictionof hydrologic

andcarbonbalancecharacteristicswithin differentborealforeststandsis givenby Kimball etal.

(1997a,b).A summaryof theimportantcomponentsofBIOME-BGCrelatingto thepredictionof daily

carbonallocationandexchangeisgivenbelow.

1.3 Objective/Purpose

In thisinvestigation,BIOME-BGCwasusedto estimatedailyandannualhydrologicandcarbon

budgetsfor differentborealforeststandsassociatedwith theBORealEcosystem-AtmosphereStudy

(BOREAS)towerflux sites,andnetcarbonflux estimateswerecomparedwithresultsderivedfrom

towerflux andbiomassmeasurement data.Theseresultswereusedto assesstheimportantclimateand

standcharacteristicsthatcontrolstandhydrologiccharacteristics,estimatedproductivityrespiration,

andsurface-atmospherecarbonexchange.

Theseresultsconstitutetheinitial effortin 1996to simulatehydrologicandcarbonexchange

processesfor differentborealforeststands.Theresultsareexpectedto changeasthemodelsare

furthermodifiedanddevelopedto reflectinsightgainedfrom newresearchregardingborealforest

processes.Theseresultsareintendedto provideaframeworkfor evaluatingthesensitivityof the

borealforestregionalcarbonbalanceto globalwarming.

1.4 Summary of Parameters and Variables

Model daily Greenwich Mean Time (GMT) input requirements:

• Maximum and minimum daily air temperature (°C)

• precipitation (cm)

• total daily solar radiation (kJ)

• daylength (s)

There is also a site initialization file that describes stand morphology and soil characteristics.

Parameters included in this file are discussed in Section 1.5. Site initialization files that were used to

generate model results for the sites in this investigation are provided.

Model daily (GMT) carbon outputs:

Net photosynthesis gross primary production (GPP); maintenance (Rm), growth (Rg),

heterotrophic (Rh), and total respiration (Rtot); net ecosystem carbon exchange (NEE). Rm represents

the daily sum of estimated Rm rates from coarse and fine root, sapwood, and foliar carbon pools.

Foliar respiration is computed as the sum of estimated day and night foliar respiration rates. GPP is

computed as the difference between gross photosynthesis and day leaf respiration. Net primary

production (NPP) is determined as the difference between GPP and Rm. Rg was estimated as 32% of

the daily difference between GPP and Rm. Rh is estimated as a proportion of prescribed soil and litter

carbon pools; estimated soil water potential and soil temperature conditions regulate this proportion.

Rtot is estimated as the sum of Rm, Rg, and Rh. NEE is estimated as the difference between GPP and

Rtot.

Model daily (GMT) hydrologic outputs:

Evaporation, transpiration, evapotranspiration, soil moisture, snow water equivalent.

1.5 Discussion

BIOME-BGC simulates biogeochemical and hydrologic processes across multiple biomes based on

the logic that differences in process rates between biomes are primarily a function of climate and

general life-form characteristics. The carbon balance portion of BIOME-BGC utilizes daily

meteorological data in conjunction with general stand and soil information to predict net

photosynthesis, growth, maintenance and heterotrophic respiration at a daily time-step. BIOME-BGC

is general in the sense that the surface is represented by singular, homogeneous canopy and soil layers.

Detailed descriptions of BIOME-BGC logic are given by Running and Coughlan (1988) and Running

Page 2
andHunt (1993).Kimball et al.(1997a,b)givesadescriptionof thecomponentsof themodelrelating

to thepredictionof hydrologicandcarboncharacteristicswithin differentborealforeststands.A

summaryof theimportantcomponentsof BIOME-BGCrelatingto thepredictionof dailycarbon

allocationandexchangeisgivenin Section3.

1.6 Related Models

Theseresultsrepresentsite-specificmodelrunsusingBIOME-BGC.BIOME-BGCwill alsobe

usedwithin thecontextof aRegionalHydro-EcologicalSimulationSystem(RHESSys)to generate

landscape-level estimatesof 1994dailyhydrologicandcarbonfluxeswithin theBOREAS1000-kinx

1000-kinstudyregion.A detaileddescriptionof theRHESSysmodelisgivenby Bandetal. (1991,

1993).

2. Investigator(s)

2.1 Investigator(s) Name and Title

Steven W. Running and John S. Kimball (TE-21 and RSS-8)

NTSG School of Forestry

University of Montana

Missoula, MT 59812

2.2 Title of Investigation

BIOME-BGC simulations of stand hydrology, productivity, surface-atmosphere carbon and water

exchange at selected BOREAS tower flux sites for 1994

2.3 Contact Information

Contact 1"

John S. Kimball

NTSG School of Forestry

University of Montana

Missoula, MT 59812

(406) 243-5616

(406) 243-4510 (fax)

email: johnk@ntsg.umt.edu

Contact 2"

Jaime Nickeson

NASA/GSFC

Code 923

Bldg. 22, Rm. C89

Greenbelt, MD 20071

(301) 286-3373

(301) 286-0239 (fax)

Jaime.Nickeson@ gsfc.nasa.gov

3. Model Theory

The sole input to the carbon budget in BIOME-BGC is the photosynthetic fixation of CO2 by the

vegetation canopy. All outputs are in the form of respired CO2, coming either from plant tissues

because of growth or maintenance respiration, or from the litter and soil carbon pools as the result of

heterotrophic respiration.

Page 3
GPPrepresentsthesystem'stotalgainof carbonby netphotosynthesisandis definedasthedaily

sumof grossphotosynthesisanddaily foliarrespiration.Thecurrentrepresentationof photosynthesis

differssignificantlyfrom previouslypublisheddescriptionsof theBGCfamily of models(Running

andHunt, 1993;HuntandRunning,1992;RunningandCoughlan,1988).Theoriginal

FOREST-BGCrepresentationof photosynthesisreliesprimarily ontheparameterizationof a

mesophyllconductanceto CO2,estimatingtherateof fixation asadiffusionprocess,drivenby a

prescribedinternalCO2concentration.FOREST-BGCalsodoesnotimplementanexplicittreatmentof

thephotosyntheticbiochemicalpathways.TheoriginalversionofBIOME-BGCpresentsamore

detailedrepresentationof photosynthesis,relyingonexplicitmodelsof photosyntheticbiochemistry

(Leuning,1990;Farquharet al., 1980).TheoriginalBIOME-BGCalsoincludesaniterative

calculationof intracellularCO2 concentration (Ci), as well as an explicit calculation of the CO2

compensation point. The current implementation of photosynthetic biochemistry is closely related to

the original BIOME-BGC logic in that it is based on the Farquhar biochemical model, but the resulting

set of equations is somewhat different because of differences in the logical constraints applied: a

quadratic system of equations is solved by eliminating Ci, instead of by specifying a value as an initial

condition. Other differences include a more detailed dependence of the kinetic parameters on

temperature (Woodrow and Berry, 1988) and a simplifying assumption that empirically relates the

maximum rate of electron transport to the maximum carboxylation velocity (Wullschleger, 1993).

Photosynthesis is regulated by the canopy conductance to CO2 (gc), leaf maintenance respiration,

and daily meteorological conditions, including air pressure, air temperature, and photosynthetically

active photon flux density (PPFD). The maximum canopy conductance to CO2 (gc max) defines the

upper boundary of the photosynthetic rate and is determined by leaf area index (LAI) and prescribed

leaf-scale boundary layer, cuticular, and maximum stomatal conductances; gc is reduced when air

temperature, vapor pressure deficit (VPD), PPFD, or soil water potential deviate from prescribed

optimal conditions (Leuning, 1990; Running and Coughlan, 1988; Jarvis and Morison, 1981).

BIOME-BGC represents the canopy as a "big leaf" in that all units of leaf area in the canopy are

represented using a single, canopy-averaged conductance. This assumption is generally not valid at

subdaily (e.g., hourly) time-steps because the reduction of irradiance at lower vertical layers of the

canopy reduces conductances at the bottom of the canopy. The big leaf assumption is strengthened,

however, by the integrative effects of a daily time-step and by the implicit assumption that the

allocation of leaf nitrogen between light harvesting and carbon fixing enzymes over depth in the

canopy varies in response to the canopy light environment, allowing an optimized use of intercepted

radiation (Evans, 1989).

Total respiration from the system (Rtot) is estimated on a daily basis as the sum of the maintenance

(Rm), heterotrophic (Rh) and growth (Rg) respiration components. Rm represents the total loss of

carbon due to day and night leaf respiration (Rdl + Rnl), sapwood (Rsw), coarse root (Rcr) and fine

root (Rfr) respiration. Respiration is estimated as a daily proportion of carbon in living tissue that is

released as the result of cellular metabolic processes, excluding any growth processes. Rm is

calculated from mean daily air temperatures and prescribed leaf, root, and sapwood carbon pools using

an exponentially increasing function of respiration with temperature following Amthor (1986). The

magnitude of the respiration response to temperature is governed by a prescribed rate defined at a

reference temperature (i.e. 15°C) and a proportional change in rate for a 10°C change in temperature

(Q10). In all cases except leaf maintenance respiration, the daily average temperature is used, and a

single value is calculated for the mass lost to maintenance respiration for the day. In the case of leaves,

however, Rdl and Rnl rates are calculated from estimated day and night air temperatures, respectively,

because Rdl is required to determine GPP. Daily growth respiration was not determined explicitly by

the model in this investigation; instead, Rg was computed as a proportion (32%) of the daily difference

between GPP and Rm (Penning de Vries et al., 1974).

The heterotrophic respiration term in BIOME-BGC represents the system's loss of carbon caused

by soil microbial respiration. Daily Rh is estimated as a proportion of prescribed soil and litter carbon

pools. The proportion of litter carbon being respired on a daily basis is regulated by soil water potential

and soil temperature conditions following Orchard and Cook (1983), Andren and Paustian (1987), and

Running and Coughlan (1988). The proportion of soil carbon respired on a daily basis was estimated

as 1% of the proportion of litter carbon respired based on data for boreal coniferous and deciduous

Page 4
stands(FoxandVanCleve, 1983;ColeandRapp,1981).

NPPrepresentsthenetaccumulationof carbonby thestandandis determinedasthedifference

betweenGPPandthesumof RmandRg.NEErepresentsthenetaccumulationor lossof carbonby

theentiresoil-standsystemandisdeterminedasthedifferencebetweenGPPandRtot.Positivefluxes

in thisinvestigationdenoteanetuptakeof carbonby thesystemwhilenegativefluxesdenoteanet

loss.Standardsfor denotingpositiveandnegativefluxesgenerallyvarybetweendifferentdisciplines,

however,andnetcarbonuptakeis oftendenotedasanegativeflux in theliterature.

BIOME-BGCusesdailymaximumandminimumairtemperatures,humidity,incidentsolar

radiation,andprecipitationto determinedailycarbonandwaterfluxes.Averagedailyincident

shortwaveradiation(Qi) wassimulatedusingMT-CLIM logic describedbyRunninget al.(1987).

Averagedailynetsolarradiation(Qn)wasestimatedusingaprescribed,constantalbedofor

vegetation.QnwasattenuatedthroughthevegetationcanopyusingBeer'sformulationanda

prescribedextinctioncoefficientmodulatedbyLAI to derivetheamountof solarradiationtransmitted

throughthecanopy(Qt).Theamountof solarradiationabsorbedby thecanopy(Qa)wasestimatedas

thedifferencebetweenQi andQt.PPFDwasestimatedbasedontheassumptionthat

photosyntheticallyactiveradiationrepresentsapproximately50%of Qa(RunningandCoughlan,

1988).

Meandailyairtemperature(Ta)wasestimatedastheaverageof themeasureddailymaximumand

minimumairtemperatures.Minimumdailyairtemperaturewasassumedequalto themeandailydew

pointandwasusedto estimatethemeandailyVPD.Daily soiltemperaturesata30-cmsoildepth

(Tsoil)wereestimatedusingan11-dayrunningaverageof Ta (Zhengetal., 1993).Soil water

potential(PSI)wasestimatedfrom soilwatercontent,soildepth,andtextureinformationfollowing

Cosbyet al. (1984).Ta,VPD,PPFD,andPSIwereusedto estimategcandGPPfollowing Jarvisand

Morison(1981)andFarquharandvonCaemmerer(1982),respectively.TaandTsoilwereusedto

estimateRm,whileTsoil andPSIwereusedto estimateRh(RunningandCoughlan,1988).

4. Equipment

BIOME-BGC is written in C with no specific hardware requirements.

5. Data Acquisition Methods

The model requires a daily meteorological data file. This file consists of six columns that are space

delimited with each row of the file representing a specific day of the year. Column 1 represents the day

of year (Julian day format, 1-365), column 2 represents precipitation (cm), column 3 represents

maximum 24-hr daily air temperature (°C), column 4 represents minimum 24 hr daily air temperature

(°C), column 5 represents total daily solar radiation (direct+diffuse, kJ), and column 6 represents the

daylength (s). A second file is also required that defines site initialization parameters such as soil, litter,

leaf and sapwood carbon pools, and soil type and condition. A detailed discussion of the development

of the tower site initialization parameter files is presented below.

BIOME-BGC requires general information about stand morphology and soil characteristics in

order to simulate the water and carbon balance at a site. Information required by the model to define

initial hydrologic characteristics of the study sites is given by Kimball et al. (1997a,b). A list of critical

parameters used to define soil and stand carbon characteristics at the eight study sites can be found

there in Table 1. These parameters were held constant throughout the model runs. Soil parameters

were derived from measurements collected at the sites during 1994 by Cuenca et al. (1997) and values

reported in the literature for representative soil types (Hillel, 1980). The soil depth was set at 0.5 m

and assumed homogeneous in regard to soil mineralized carbon, structure, and soil moisture

characteristics. Mean daily stand solar albedos for snow-free conditions were estimated from site

observations (Sellers et al., 1995).

Estimates of average annual LAI were derived from effective LAI measurements conducted over

Page 5
approximatelythreeperiodsduringthe1994growingseasonateachstudysiteby Chen(1996).

EffectiveLAI wasmeasuredusingaLI-CORLAI-2000plantcanopyanalyzerandadjustedfor foliage

clumping.Specificleafarea(SLA)andleafnitrogenlevelsweredeterminedfrom pluckedneedleand

leafmeasurementsatthespruce,jack pine,andaspensitesby Margolisetal. (1996unpublisheddata).

Theamountsof leafnitrogenin ribulosebisphosphatecarboxylase-oxygenase(RuBisCO)were

estimatedfrom theliteratureforrepresentativecovertypes(FieldandMooney,1986).Leaf carbonwas

derivedfrom LAI andSLA information.Sapwoodcarbonwasestimatedfrom sapwoodbiomass

measurementscollectedby Goweret al.(1996unpublisheddata)at theblackspruce,aspenandjack

pinesitesandestimatesof therelativeproportionsof sapwoodlive cells(WaringandSchlesinger,

1985).Coarserootcarbonwasestimatedto beapproximately25%of sapwoodcarbon(e.g.,Grieret

al., 1981;Grier andLogan,1977).

Theamountof carbonattributedto finerootbiomassishighly variabledependingonspeciestype,

standage,andnutrientavailability.Processesgoverningthepartitioningof carbonbetweenroot and

foliar biomassaregenerallypoorlyunderstoodandnotwell quantifiedin theliterature.Observations

haveshown,however,thatfinerootbiomassis generallygreaterthanfoliar biomassin nutrient-limited

systems,whichoftenoccurin borealandcold temperateforestsandmayrepresentanadaptationto

maximizenutrientuptake(Nadelhofferetal., 1985;KeyesandGrier, 1981;Tetrealtet al., 1978).Soil

carbonattributedto finerootswasestimatedfrom 1.5SouthernStudyAreaOld Aspen(SSA-OA)to

3.5SSA-OldJackPine(OJP)timestheestimatedleaf carbonbasedonobservationsfrom borealand

cold temperateconiferousanddeciduousstandsonnutrient-poorsites(Goweret al., 1992;Comeau

andKimmins, 1989;Nadelhofferetal.; 1985;LinderandAxelson,1982;PeralaandAlban, 1982;

KeyesandGrier, 1981).Soil litter andmineralizedorganiccarbonpoolswithin theprescribed0.5-m

soildepthswereestimatedfrom soillayerdepth,bulk densityandpercentorganiccarbon

measurementsconductedateachof thestudysitesby Andersonetal. (1995unpublisheddata).

Leaf,stem,coarse,andfinerootmaintenancerespirationcoefficientswereestimatedfrom

measuredratesfor coniferousanddeciduouscovertypes(Sprugelet al., 1995).All other

ecophysiologicalparameterswereobtainedfrom theliteraturefor generalcovertypes(e.g.,Sprugelet

al., 1995;Nobel, 1991;Waring andSchlesinger,1985).

6.1 Data Notes

None.

6.2 Field Notes

None.

6. Observations

7. Data Description

7.1 Spatial Characteristics

7.1.1 Spatial Coverage

These results constitute point simulations of the BOREAS NSA-Old Black Spruce (NOBS) and

Young Jack Pine (NYJP) and SSA-Old Aspen (SOA), Old Black Spruce (SOBS) and Old Jack Pine

(SOJP) tower flux sites.

7.1.2 Spatial Coverage Map

Not applicable.

7.1.3 Spatial Resolution

Tower site.

Page 6
7.1.4 Projection

Not applicable.

7.1.5 Grid Description

Not applicable.

7.2 Temporal Characteristics

7.2.1 Temporal Coverage

BIOME-BGC was run over a 2-year period at each study site. The model was initialized using

1989 AMS mesonet station meteorological data from the Thompson airport (55.8 ° N, 97.9 ° W) for

study sites in the Northern Study Area (NSA), and from Prince Albert airport (53.2 ° N, 105.7 ° W) and

Waskesiu Lake (53.9 ° N, 106.1 ° W) for study sites in the SSA (Shewchuk, 1997). All analyses of

model results were done for the second year using the 1994 meteorological data base described in

Section 7.3.

7.2.2 Temporal Coverage Map

Not applicable.

7.2.3 Temporal Resolution

Daily.

7.3 Data Characteristics

BIOME-BGC requires two input files (daily meteorological data and initialization data) to generate

two output files of daily estimates of site hydrologic and carbon balance characteristics. The

initialization file provides site-specific information about stand morphology, soil type, and soil

condition. The meteorological data file and output files are described further in subsequent sections.

Organized by site, the names of the initialization, meteorology, and output files provided are:

NSA-OBS-FLXTR.IN INI

NSA-OBS-FLXTR.IN MET

NSA-OBS-FLXTR.OUT CARB

NSA-OBS-FLXTR.OUT HYD

NSA-YJP-FLXTR.IN INI

NSA-YJP-FLXTR.IN MET

NSA-YJP-FLXTR.OUT CARB

NSA-YJP-FLXTR.OUT HYD

SSA-9OA-FLXTR.IN INI

SSA-9OA-FLXTR.IN MET

SSA-9OA-FLXTR.OUT CARB

SSA-9OA-FLXTR.OUT HYD

SSA-OBS-FLXTR.IN INI

SSA-OBS-FLXTR.IN MET

SSA-OBS-FLXTR.OUT CARB

SSA-OBS-FLXTR.OUT HYD

SSA-OJP-FLXTR.IN INI

SSA-OJP-FLXTR.IN MET

SSA-OJP-FLXTR.OUT CARB

SSA-OJP-FLXTR.OUT HYD

Page 7
Air temperature,solarradiation,andprecipitationweremeasuredat approximate15-minuteintervalsat

eachof thestudysitesduring1994.ThesedatawereobtainedfromBOREASprincipalinvestigatorsat

eachstudysiteandtheSaskatchewanResearchCouncil'smesonetdatabase(BOREASScienceTeam

1995).The1994meteorologicalrecordsfor eachstudysitewereincompletebecauseof periodsof

instrumentmalfunction,calibration,andmeasurement inactivity.Continuousmeteorologicalrecords

for 1994wereobtainedfor eachstudysiteby temporallyinterpolatingmissingdataor substitutingdata

from adjacentsites.Daily maximumandminimumairtemperatures,precipitation,andsolarradiation

werethenderivedfrom thecontinuousdatarecordsfor eachsiteandusedto generatemodelresults.

7.3.1 Parameter/Variables

Input Meteorological data:

DOY PCP TMAX TMIN SOLIN DAYLEN

Output Hydrologic Data:

DOY SNOWW SOILW T ET E Q

Output Carbon data:

DOY GPP Rdl Rnl Rsw Rcr

**NOTE: NEE denoted with a

from the stand to the atmosphere, while

net carbon uptake by the stand.

7.3.2 Variable Description/Definition

Input Meteorological data:

Rfr Rh Rm Rg NPP NEE Rtot

(-) sign indicates net carbon release

a positive sign indicates

DOY Day of year (1-365)

PCP daily precipitation (cm)

TMAX maximum 24-hour air temperature

TMIN minimum 24-hour air temperature

SOLIN total daily solar radiation (kJ)

DAYLEN daylength (s)

Output Hydrologic Data:

(°C)

(°C)

DOY julian day

SNOWW Snow water equivalent of the snowcover (mm)

SOILW Water held in the soil layer (mm)

T Transpiration from the canopy (kg/m 2 day)

ET Evapotranspiration (kg/m 2 day)

E Evaporation from the canopy and surface (kg/m 2 day)

Q outflow (ram/day)

Output Carbon data:

production (mg C/m 2 day)

DOY

GPP

Rdl

Rnl

Rsw

Rcr

Julian day

Net daily photosynthesis or gross primary

Daytime leaf respiration (mg C/m 2 day)

Night leaf respiration (mg C/m 2 day)

Sapwood respiration (mg C/m 2 day)

Coarse root respiration (mg C/m 2 day)

Page 8
Rfr

Rh

Rm

Rg

NPP

NEE

Rtot

Fine root respiration (mg C/m 2 day)

Heterotrophic respiration (mg C/m 2 day)

Maintenance respiration (mg C/m 2 day)

Growth respiration (mg C/m 2 day)

Net primary production (mg C/m 2 day)

Net ecosystem carbon exchange (mg C/m 2 day); (-) sign indicates net

release to the atmosphere, while a positive sign indicates net

carbon uptake by the stand.

Total respiration (mg C/m 2 day)

7.3.3 Unit of Measurement

Input Meteorological data:

DOY days

PCP centimeters

TMAX degrees Celcius

TMIN degrees Celcius

SOLIN kilo-Joules

DAYLEN seconds

Output Hydrologic Data:

DOY day

SNOWW mm

SOILW mm

T kg/m 2 day

ET kg/m 2 day

E kg/m 2 day

Q mm/day

Outut Carbon data:

GPP mg C/m 2 day

Rdl mg C/m 2 day

Rnl mg C/m 2 day

Rsw mg C/m 2 day

Rcr mg C/m 2 day

Rfr mg C/m 2 day

Rh mg C/m 2 day

Rm mg C/m 2 day

Rg mg C/m 2 day

NPP mg C/m 2 day

NEE mg C/m 2 day

Rtot mg C/m 2 day

7.3.4 Data Source

Daily meteorological data were derived from approximate 15 minute measurements obtained from

SRC mesonet and flux tower sites for 1994 (BOREAS Science Team 1995; Shewchuk, 1997). The

initialization data files were created using information obtained from measurements by other BOREAS

investigators and the literature for similar stand types (see Section 5).

Hydrologic and carbon data were outputs from the BIOME-BGC model.

7.3.5 Data Range

None given.

Page 9
7.4 Sample Data Record

Sample records from selected input and output files are:

Input Meteorological data file sample:

i 0.00 -28.50 -42.00 16.40 24467

2 0.00 -25.50 -42.40 28.70 24554

3 0.04 -15.70 -30.70 23.40 24649

Output Hydrologic data file sample:

DOY SNOWW SOILW T ET E Q

1 55.39 190.00 0.00 0.01 0.01 0.00

2 55.78 190.00 0.00 0.01 0.01 0.00

3 55.77 190.00 0.00 0.01 0.00 0.00

Output Carbon data file sample:

DOY GPP Rdl Rnl Rsw Rcr Rfr Rh Rm Rg NPP NEE Rtot

1 ii 43 92 39 i0 278 0 462 0.0 -451 -451 462

2 14 46 91 41 i0 289 0 477 0.0 -463 -463 477

3 22 53 113 48 12 338 0 564 0.0 -542 -542 564

8. Data Organization

8.1 Data Granularity

The smallest unit of obtainable data is the entire modeling data set, which contains a total of 20

input and output American Standard Code for Information Interchange (ASCII) files, and this

document.

8.2 Data Format(s)

The model input and output files are in ASCII format with space-delimited columns.

9. Data Manipulations

See Kimball et al. (1997a,b) and Running and Hunt (1993) for detailed descriptions of model,

methods, and processing steps.

9.1 Formulae

See Section 9.

9.1.1 Derivation Techniques and Algorithms

See Section 9.

9.2 Data Processing Sequence

See Section 9.

9.2.1 Proeessing Steps

See Section 9.

Page 10
9.2.2 Processing Changes

See Section 9.

9.3 Calculations

See Section 9.

9.3.1 Special Corrections/Adjustments

Not applicable.

9.3.2 Calculated Variables

See Sections 7.3.1 and 7.3.272.

9.4 Graphs and Plots

Not applicable.

10. Errors

10.1 Sources of Error

BIOME-BGC is a process-level model designed to be general enough to apply at regional to global

scales. The model uses several simplifying assumptions regarding stand and meteorological conditions

in order to facilitate application at regional scales. A fundamental model assumption for this

investigation was that stand physiological conditions such as age, stand structure, LAI, and carbon

storages were spatially and temporally uniform on an annual basis. Soil conditions such as depth,

density, and moisture content were also assumed spatially uniform with no lateral or subsurface

drainage. Stand conditions at the study sites were both spatially and temporally diverse and were

composed of different age types, biomass densities, and species compositions (Sellers et al., 1995).

Some sites also had significant vegetation understories that were not explicitly modeled in this

investigation. Evidence suggests that these vegetation types contributed significantly to the daily

carbon budget (e.g., Black et al., 1996). Further discussion of potential error sources for this

investigation is given by Kimball et al. (1997a,b).

10.2 Quality Assessment

See Section 10.1.

10.2.1 Model Validation by Source

Model results were compared with daily carbon and water fluxes derived from site tower flux

measurements for 1994. Model estimates of annual NPP were also compared with NPP estimates

derived from site biomass measurements and allometric equations for 1994 (Gower et al., unpublished

data). Model estimates of SNOWW and SOILW were compared with measured data for 1994

(Shewchuck, 1997). Detailed discussions of these comparisons are given by Kimball et al. (1997a,b).

10.2.2 Confidence Level/Accuracy Judgment

Currently, there is not enough information regarding measurement error associated with model

inputs or model sensitivity to these inputs to establish documented confidence levels in model results.

This problem is currently being addressed using sensitivity analyses with multiple-year data and spatial

aggregations of remote sensing inputs for the BOREAS region. This work is being funded under a

different, but related, project with the jet propulsion Laboratory (JPL). Also see Section 10.2.1.

10.2.3 Measurement Error for Parameters

See Section 10.2.2.

10.2.4 Additional Quality Assessments

See Sections 10.1 and 10.2.1.

Page 11
10.2.5 Data Verification by Data Center

BOREAS Information System (BORIS) staff have looked at the input and output files and

reviewed the model documentation.

11.

11.1 Limitations of the Model

See Sections 10.1 and 10.2.1.

11.2 Known Problems with the Model

See Sections 10.1 and 10.2.1.

11.3 Usage Guidance

None.

11.4 Other Relevant Information

None.

Notes

12. Application of the Model

These results constitute the initial effort in 1996 to simulate hydrologic and carbon exchange processes

for different boreal forest stands. These results are expected to change as the models are further

modified and developed to reflect insight gained from new research regarding boreal forest processes.

These results are intended for comparison with other models.

13. Future Modifications and Plans

This model will be used in the context of RHESSys to generate landscape-level estimates of daily and

annual water and carbon exchange processes over the 1,000-kin x 1,000-kin BOREAS grid at a 1-kin

spatial resolution.

Carbon allocation, growth respiration, and nitrogen cycle routines will be activated (see Running

and Hunt, 1993), and model runs will be conducted over longer time periods (50 to several hundred

years) to investigate the effects of interannual climate variations on site to regional water and carbon

budgets.

A sensitivity analysis with multiple-year data and spatial aggregations of remote sensing inputs for

the BOREAS region is currently underway. This work is being funded under a different, but related,

project with JPL.

14. Software

14.1 Software Description

BIOME-BGC was written in C on a UNIX platform.

14.2 Software Access

To request a copy of the model, please send email to one of the individuals from the University of

Montana listed in Section 2.3.

14.3 Software/Platform Limitations

None known.

Page 12
15. Data Access

The RSS-08 BIOME-BGC model files are available from the Earth Observing System Data and

Information System (EOSDIS) Oak Ridge National Laboratory (ORNL) Distributed Active Archive

Center (DAAC).

15.1 Contact Information

For BOREAS data and documentation please contact:

ORNL DAAC User Services

Oak Ridge National Laboratory

P.O. Box 2008 MS-6407

Oak Ridge, TN 37831-6407

Phone: (423) 241-3952

Fax: (423) 574-4665

E-mail: ornldaac@ornl.gov or ornl@eos.nasa.gov

15.2 Data Center Identification

Earth Observing System Data and Information System (EOSDIS) Oak Ridge National Laboratory

(ORNL) Distributed Active Archive Center (DAAC) for Biogeochemical Dynamics

http://www-eosdis.ornl.gov/.

15.3 Procedures for Obtaining Data

Users may obtain data directly through the ORNL DAAC online search and order system

[http://www-eosdis.ornl.gov/] and the anonymous FTP site [ftp://www-eosdis.ornl.gov/data/] or by

contacting User Services by electronic mail, telephone, fax, letter, or personal visit using the contact

information in Section 15.1.

15.4 Data Center Status/Plans

The ORNL DAAC is the primary source for BOREAS field measurement, image, GIS, and

hardcopy data products. The BOREAS CD-ROM and data referenced or listed in inventories on the

CD-ROM are available from the ORNL DAAC.

16. Output Products and Availability

16.1 Tape Products

None.

16.2 Film Products

None.

16.3 Other Products

Model results are stored as ASCII files and are available either online or by contacting BORIS staff

directly. See Section 15.1.

Page 13
17. References

17.1 Model Documentation

Band, L.E., D.L. Peterson, S.W. Running, J.C. Coughlan, R.B. Lammers, J. Dungan, and R.

Nemani. 1991. Forest ecosystem processes at the watershed scale: basis for distributed simulation.

Ecological Modelling, 56:151-176.

Band, L.E., P. Patterson, R. Nemani, and S.W. Running. 1993. Forest ecosystem processes at the

watershed scale: incorporating hillslope hydrology. Agric. For. Meteorol., 63: 93-126.

Hunt, R.E. and S.W. Running. 1992. Simulated dry matter yields for aspen and spruce stands in the

North American boreal forest. Canadian Journal of Remote Sensing, 18(3): 126-133.

Kimball, J.S., M.A. White, and S.W. Running. 1997a. BIOME-BGC simulations of BOREAS stand

hydrologic processes. Journal of Geophysical Research (in press).

Kimball, J.S., P.E. Thornton, M.A. White, and S.W. Running. 1997b. Simulating forest

productivity and surface-atmosphere carbon exchange in the BOREAS study region. Tree Physiology,

17, 589-599.

Running, S.W. and J.C. Coughlan. 1988. A general model of forest ecosystem processes for regional

applications, I. hydrologic balance, canopy gas exchange and primary production processes.

Ecological Modelling, 42:125-154.

Running, S.W. and R.E. Hunt. 1993. Generalization of a forest ecosystem process model for other

biomes, BIOME-BGC, and an application for global-scale models. In Scaling Physiologic Processes:

Leaf to Globe. Eds. J.R. Ehleringer and C.B. Field. Academic Press, San Diego, CA, pp. 141-158.

17.2 Journal Articles and Study Reports

Amthor, J.S. 1986. Evolution and applicability of a whole plant respiration model. Journal of

Theoretical Biology, 122: 473-490.

Andren, O. and K. Paustian. 1987. Barley straw decomposition in the field: a comparison of models.

Ecology, 68(5): 1190-1200.

Black, T.A., G. den Hartog, H.H. Neumann, P.D. Blanken, P.C. Yang, C. Russell, Z. Nesic, X.

Lee, S.G. Chen, and R. Staebler. 1996. Annual cycles of water vapour and carbon dioxide fluxes in

and above a boreal aspen forest. Global Change Biology, 2:219-229.

Bonan, G.B. and H.H. Shugart. 1989. Environmental factors and ecological processes in boreal

forests. Annual Review of Ecology and Systematics, 20:1-28.

Chen, J.M. 1996. Optically-based methods for measuring seasonal variation of leaf area index in

boreal conifer stands. Agricultural and Forest Meteorology, 80:135-163.

Cole, D.W. and M. Rapp. 1981. Elemental cycling in forest ecosystems. In Dynamic Principles of

Forest Ecosystems. Ed. D.E. Reichle. Cambridge University Press, London and New York, pp.

341-409.

Comeau, P.G. and J.P. Kimmins. 1989. Above- and below-ground biomass and production of

lodgepole pine on sites with differing soil moisture. Canadian Journal of Forest Res., 19:447-454.

Cosby, B.J., G.M. Hornberger, R.B. Clapp, and T.R. Ginn. 1984. A statistical exploration of the

relationships of soil moisture characteristics to the physical properties of soils. Water Resources

Research, 20:682-690.

Page 14
Edwards,N.T., H.H. Shugart,S.B.McLaughlin, W.F. Harris, andD.E. Reichle.1981.Carbon

metabolismin terrestrialecosystems.In InterBiol.ProgrammeNo. 23,"DynamicPropertiesof Forest

Ecosystems."Ed. D.E.Reichle.CambridgeUniversityPress,LondonandNewYork, pp499-536.

Evans,J.R.1989.Photosynthesisandnitrogenrelationshipsin leavesof C3plants.Oecologia,

78:9-19.

Farquhar,G.D. 1989.Modelsof integratedphotosynthesisof cellsandleaves.Phil. Trans.Roy.Soc.

Lond., 323B:357-367.

Farquhar,G.D. andS.vonCaemmerer.1982.Modellingof photosyntheticresponseto environmental

conditions.In Encyclopediaof PlantPhysiology,New Series,Vol. 12B,"PhysiologicalPlant

EcologyII." Eds.O.L. Lange,P.S.Nobel,C.B. Osmond,andH. Ziegler.SpringerVerlag,Berlin,

Germany,pp. 549-587.

Farquhar,G.D.,S.von Caemmerer,andJ.A.Berry. 1980.A biochemicalmodelof photosynthetic

CO2assimilationin leavesof C3species.Planta,149:78-90.

Field,C. andH.A. Mooney.1986.Thephotosynthesis-nitrogenrelationshipin wild plants.In On the

EconomyofPlantForm andFunction.Ed. T.J.Givnish.CambridgeUniversityPress,Cambridge,

pp. 25-55.

Fox, J.F.andK. VanCleve.1983.Relationshipsbetweencellulosedecomposition,Jenny'sk,

forest-floornitrogen,andsoiltemperaturein Alaskantaigaforests.CanadianJournalof Forest

Research,13:789-794.

Gates,D.M. 1993.Plant-AtmosphereRelationships.ChapmanandHall, NewYork, 92p.

Gower,S.T.,K.A. Vogt, andC.C.Grier. 1992.Carbondynamicsof RockyMountainDouglas-fir:

Influenceof waterandnutrientavailability.EcologicalMonographs,62:43-65.

Grier, C.C.andR.S.Logan.1981.Old-growthpseudotsugamenziesiicommunitiesof awestern

Oregonwatershed:biomassdistributionandproductionbudgets.EcologicalMonographs,

47:373-400.

Grier, C.C.,K.A. Vogt, M.R. Keyes,andR.L.Edmonds.1981.Biomassdistribution andaboveandbelow-groundproductionin youngandmatureAbiesamabiliszoneecosystemsof theWashington

Cascades.CanadianJournalof ForestResearch,11:155-157.

Hillel, D. 1980.Fundamentalsof Soil Physics.AcademicPress,NewYork, 413p.

Jarvis,P.G.andJ.I.L. Morison. 1981.Stomatalcontrol of transpirationandphotosynthesis.In

StomatalPhysiology.Eds.P.G.JarvisandT.A. Mansfield.CambridgeUniversityPress,Cambridge,

pp. 247-279.

Keyes,M.R. andC.C.Grier. 1981.Above-andbelow-groundnetproductionin 40-year-old

Douglas-firstandsonhigh andlow productivity sites.CanadianJournalof ForestRes.,11:599-605.

Kinerson,R.S.,C.W.Ralston,andC.G.Wells. 1977.Carboncyclingin aloblolly pineplantation.

Oecologia,29:1-10.

Leuning,R. 1990.Modelingstomatalbehaviorandphotosynthesisof EucalyptusGrandis.Australian

Journalof PlantPhysiology,17:159-175.

Page15
Linder,S.andB.Axelsson.1982.Changesin carbonuptakeandallocationpatternsasaresultof

irrigationandfertilizationin ayoungPinussylvestrisstand.In "CarbonUptakeandAllocation:Keyto

Managementof SubalpineForestEcosystems."Ed.R.H. Waring.InternationalUnionForest

ResearchOrganization(IUFRO)Workshop,ForestResearchLaboratory,OregonStateUniversity,

Corvallis,Oregon,pp. 38-44.

Malkonen,E. 1974.Annualprimaryproductionandnutrientcyclein some Scots pine stands.

Commun. Inst. For. Fenn. (Helsinki), No. 84.

Nadelhoffer, K.J., J.D. Aber, and J.M. Melillo. 1985. Fine root production in relation to total net

primary production along a nitrogen mineralization gradient in temperate forests: a new hypothesis.

Ecology, 66:1377-1390.

Nobel, P.S. 1991. Physicochemical and Environmental Plant Physiology. Academic Press Inc., New

York, 635 p.

Orchard, V.A. and F.J. Cook. 1983. Relationship between soil respiration and soil moisture. Soil

biology and Biochemistry, 15(4):447-453.

Paavilainen, E. 1980. Effect of fertilization on plant biomass and nutrient cycle on a drained dwarf

shrub pine swamp. Comm. Inst. For. Fenn. (Helsinki), No. 98.

Penning de Vries, F.W.T., A. Brunsting, and H.H. Van Laar. 1974. Products, requirements and

efficiency of biosynthesis: A quantitative approach. Journal of Theoretical Biology, 45:339-377.

Perala, D.A. and D.H. Alban. 1982. Biomass, nutrient distribution and litterfall in Populus, Pinus and

Picea stands on two different soils in Minnesota. Plant and Soil, 64:177-192.

Rastetter, E.B., A.W. King, B.J. Cosby, G.M. Hornberger, R.V. O'Neill, and J.E. Hobbie. 1992.

Aggregating fine-scale ecological knowledge to model coarser-scale attributes of ecosystems.

Ecological Applications, 2:55-70.

Running, S.W., R.R. Nemani, and R.D. Hungerford. 1987. Extrapolation of synoptic meteorological

data in mountainous terrain and its use for simulating forest evapotranspiration and photosynthesis.

Canadian Journal of Forest Research, 17:472-483.

Sellers, P. and F. Hall. 1994. Boreal Ecosystem-Atmosphere Study: Experiment Plan. Version

1994-3.0, NASA BOREAS Report (EXPLAN 94).

Sellers, P., F. Hall, H. Margolis, B. Kelly, D. Baldocchi, G. den Hartog, J. Cihlar, M.G. Ryan, B.

Goodison, P. Crill, K.J. Ranson, D. Lettenmaier, and D.E. Wickland. 1995. The boreal

ecosystem-atmosphere study (BOREAS): an overview and early results from the 1994 field year.

Bulletin of the American Meteorological Society. 76(9): 1549-1577.

Sellers, P., F. Hall, and K.F. Huemmrich. 1996. Boreal Ecosystem-Atmosphere Study: 1994

Operations. NASA BOREAS Report (OPS DOC 94).

Sellers, P. and F. Hall. 1996. Boreal Ecosystem-Atmosphere Study: Experiment Plan. Version

1996-2.0, NASA BOREAS Report (EXPLAN 96).

Sellers, P., F. Hall, and K.F. Huemmrich. 1997. Boreal Ecosystem-Atmosphere Study: 1996

Operations. NASA BOREAS Report (OPS DOC 96).

Page 16
Sellers,P.J.,F.G.Hall, R.D.Kelly, A. Black, D. Baldocchi,J. Berry, M. Ryan,K.J. Ranson,P.M.

Crill, D.P.Lettenmaier,H. Margolis,J.Cihlar, J.Newcomer,D. Fitzjarrald,P.G.Jarvis,S.T.

Gower,D. Halliwell, D. Williams, B. Goodison,D.E.Wickland, andF.E. Guertin.(1997).

"BOREASin 1997:ExperimentOverview,ScientificResultsandFutureDirections",Journalof

GeophysicalResearch(JGR),BOREASSpecialIssue,102(D24),Dec. 1997,pp.28731-28770.

Shewchuk,S.R.1997.Thesurfaceatmosphericsciencesmesonetfor BOREAS.Journalof

GeophysicalResearch(inpress).

Sprugel,D.G.,M.G. Ryan,J.R.Brooks,K.A. Vogt, andT.A. Martin. 1995.Respirationfrom the

organlevelto thestand.In ResourcePhysiologyof Conifers,Acquisition,AllocationandUtilization.

Eds.W.K. SmithandT.M. Hinckley. AcademicPress,SanDiego,pp. 255-299.

Tetreault,J.P.,B. Bernier,andJ.A. Fortin. 1978.Nitrogenfertilization andmycorrhizaeof balsamfir

seedlingsin naturalstands.NaturalisteCanadien(Quebec)105:461-466.

Waring,R.H. andW.H. Schlesinger.1985.ForestEcosystemsConceptsandManagement.Academic

PressInc., SanDiego,340p.

Woodrow,I.E. andJ.A.Berry. 1988.Enzymaticregulationof photosyntheticCO2 fixation in C3

plants. Annual Reviews of Plant Physiology and Plant Molecular Biology, 39:533-594.

Wullschleger, S.D. 1993. Biochemical limitations to carbon assimilation in C3 plants - a retrospective

analysis of the A/Ci curves from 109 species. Journal of Experimental Botany, 44:907-920.

Zheng, D., E.R. Hunt, and S.W. Running. 1993. A daily soil temperature model based on air

temperature and precipitation for continental applications. Climate Research, 2:183-191.

17.3 Archive/DBMS Usage Documentation

None.

None.

18. Glossary of Terms

ASCII

BOREAS

BORIS

DAAC

DAYLEN

DOY

E

EOS

EOSDIS

ET

gC

GMT

GPP

GSFC

19. List of Acronyms

- American Standard Code for Information

- BOReal Ecosystem-Atmosphere Study

- BOREAS Information System

- Distributed Active Archive Center

- daylength (s)

- day of year or Julian day

- Evaporation from the canopy and

- Earth Observing System

- EOS Data and Information System

- Evapotranspiration (kg/m 2 day)

- Canopy Conductance

- Greenwich Mean Time

- Gross Primary Production (mg C/m 2 day)

- Goddard Space Flight Center

Interchange

surface (kg/m 2 day)

Page 17
JPL

LAI

NASA

NEE

NPP

NSA

OA

OBS

OJP

ORNL

PANP

PCP

PPFD

PSI

Q

Rcr

Rdl

Rfr

Rg

Rh

- Jet Propulsion Laboratory

- Leaf Area Index (m2/m 2)

- National Aeronautics and Space Administration

- Net Ecosystem Carbon Exchange (mg C/m 2 day)

- Net Primary Production (mg C/m 2 day)

- Northern Study Area

- Old Aspen

- Old Black Spruce

- Old Jack Spruce

- Oak Ridge National Laboratory

- Prince Albert National Park

- Daily Precipitation (cm)

- Photosynthetically Active Photon Flux Density

- Soil Water Potential

- Outflow (mm/day)

- Coarse root respiration rate (mg C/m 2 day)

- Daytime leaf respiration rate (mg C/m 2 day)

- Fine root respiration rate (mg C/m 2 day)

- Growth respiration (mg C/m 2 day)

- Heterotrophic respiration (mg C/m 2 day)

RHESSYS - Regional Hydro-EcologicalSimulation System

Rm - Maintenance respiration (mg C/m 2 day)

Rnl - Nighttime leaf respiration rate (mg C/m 2 day)

RSS - Remote Sensing Science

Rsw - Sapwood respiration rate (mg C/m 2 day)

Rtot - Total respiration (mg C/m 2 day)

RuBisCO - Ribulose Bisphosphate Carboxylase-Oxygenase

SLA

SOILW

SOLIN

SNOWW

SSA

T

TE

TMAX

TMIN

URL

YJP

- Specific leaf area (m2/kg C)

- Water held in the Soil Layer (ram)

- Total Daily Solar Radiation (kJ)

- Snow Water Equivilent of the Snowcover (mm)

- Southern Study Area

- Transpiration from the canopy (kg/m 2 day)

- Terrestrial Ecology

- maximum 24-hour air temperature (°C)

- minimum 24-hour air temperature (°C)

- Uniform Resource Locator

- Young Jack Pine

20. Document Information

20.1 Document Revision Date

Written: 19-Sep- 1996

Last Updated: 06-Oct- 1998

20.2 Document Review Date(s)

BORIS Review: 16-Sep-1997

Science Review: 01-Nov- 1997

20.3 Document ID

Page 18
20.4 Citation

WhenusingBIOME-BGC,pleaseincludethefollowing acknowledgmentaswell ascitationsof

relevantpapersin Section17.1:

If usingdatafromtheBOREASCD-ROM series,alsoreferencethedataas:

Running,S.W,J.S.Kimball, "BIOME-BGC ModelSimulationsat TowerFlux Sites."In

CollectedDataof TheBorealEcosystem-AtmosphereStudy.Eds.J.Newcomer,D. Landis,S.

Conrad,S.Curd,K. Huemmrich,D.Knapp,A. Morrell, J.Nickeson,A. Papagno,D. Rinker,R.

Strub,T. Twine,F. Hall, andP. Sellers.CD-ROM. NASA, 2000.

Also,citetheBOREASCD-ROMsetas:

Newcomer,J.,D. Landis,S.Conrad,S.Curd,K. Huemmrich,D. Knapp,A. Morrell, J.

Nickeson,A. Papagno,D. Rinker,R.Strub,T. Twine,F. Hall, andP.Sellers,eds.CollectedDataof

TheBorealEcosystem-AtmosphereStudy.NASA. CD-ROM.NASA, 2000.

20.5 Document Curator

20.6 Document URL

Page 19
REPORT DOCUMENTATION PAGE FormApproved

OMB No. 0704-0188

Public reporting burden for this collection of informationis estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources,

gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this

collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson

Davis Highway, Suite 1204, Arlington, VA 22202-4302, and to the Office of Management and Budget, Paperwork Reduction Project (0704-0188), Washington, DC 20503.

1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED

August 2000 Technical Memorandum

4. TITLE AND SUBTITLE

Technical Report Series on the Boreal Ecosystem-Atmosphere Study (BOREAS)

BOREAS RSS-8 BIOME-BGC Model Simulations at Tower Flux Sites in 1994

6. AUTHOR(S)

John Kimball

Forrest G. Hall and Jaime Nickeson, Editors

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS (ES)

Goddard Space Flight Center

Greenbelt, Maryland 20771

9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS (ES)

National Aeronautics and Space Administration

Washington, DC 20546-0001

5. FUNDING NUMBERS

923

RTOP: 923-462-33-01

8. PEFORMING ORGANIZATION

REPORT NUMBER

2000-03136-0

10. SPONSORING / MONITORING

AGENCY REPORT NUMBER

TM--2000-209891

Vol. 54

11. SUPPLEMENTARY NOTES

J. Kimball: University of Montana; J. Nickeson: Raytheon ITSS

12a. DISTRIBUTION / AVAILABILITY STATEMENT

Unclassifie_Unlimited

Subject Category: 43

Report available from the NASA Center for AeroSpace Information,

7121 Standard Drive, Hanover, MD 21076-1320. (301) 621-0390.

12b. DISTRIBUTION CODE

13. ABSTRACT (Maximum 200 words)

BIOME-BGC is a general ecosystem process model designed to simulate biogeochemical and hydrologic processes across multiple scales (Running and Hunt, 1993). In this investigation, BIOME-BGC

was used to estimate daily water and carbon budgets for the BOREAS tower flux sites for 1994.

Carbon variables estimated by the model include gross primary production (i.e., net photosynthesis),

maintenance and heterotrophic respiration, net primary production, and net ecosystem carbon exchange. Hydrologic variables estimated by the model include snowcover, evaporation, transpiration,

evapotranspiration, soil moisture, and outflow. The information provided by the investigation includes

input initialization and model output files for various sites in tabular ASCII format.

14. SUBJECT TERMS

BOREAS, remote sensing science, BIOME-BGC.

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