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Use of Biome-BGC with the ChEAS flux tower network to address scaling issues

Use of Biome-BGC with the ChEAS flux tower network to address scaling issues. Faith Ann Heinsch NTSG, School of Forestry The University of Montana ChEAS Meeting July 1, 2003. The BIOME-BGC Terrestrial Ecosystem Process Model.

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Use of Biome-BGC with the ChEAS flux tower network to address scaling issues

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  1. Use of Biome-BGC with the ChEAS flux tower network to address scaling issues Faith Ann Heinsch NTSG, School of Forestry The University of Montana ChEAS Meeting July 1, 2003

  2. The BIOME-BGC Terrestrial Ecosystem Process Model • BIOME-BGC estimates fluxes and storage of energy, water, carbon, and nitrogen for vegetation and soil on a daily basis. • Model algorithms represent physical and biological processes that control fluxes of energy and mass: • New leafgrowth and old leaflitterfall • Sunlight interception by leaves, and penetration to the ground • Precipitation routing to leaves and soil • Snow (SWE) accumulation and melting • Drainage and runoff of soil water • Evaporation of water from soil and wet leaves • Transpiration of soil water through leaf stomata • Photosynthetic fixation of carbon from CO2 in the air • N uptake from the soil • Distribution of C and N to growing plant parts • Decomposition of fresh plant litter and old soil organic matter • Plant mortality • Plant phenology • Fire/disturbance

  3. Major Features: • Daily time step (day/night partitioning based on daily information) • Single, uniform soil layer hydrology (bucket model) • 1 uniform snow layer of SWE (no canopy snow interception/losses) • 1 canopy layer (sunlit/shaded leaf partitioning) • Dynamic phenology and C/N allocation (e.g. LAI, biomass, soil and litter) • Disturbance (fire) and mortality functions • Variable litter and soil C decomposition rates (3 litter and 4 soil C pools) BIOME-BGC

  4. Meteorological Parameters Required by Biome-BGC • Daily maximum temperature (°C) • Daily minimum temperature (°C) • Daylight average temperature (°C) • Daily total precipitation (cm) • Daylight average partial pressure of water vapor (Pa) • Daylight average shortwave radiant flux density (W/m2) • Daylength (s)

  5. Site Data Latitude Elevation Slope/Aspect Soil Depth Soil Texture Meteorological Data Air Temperature Radiation Precipitation Humidity Atmospheric CO2 Daily - Annual Photosynthesis Evapotranspiration Respiration Absorbed PAR Atmospheric CO2 PSN GR MR Evaporation/ Transpiration Temperature Periodic Input  Disturbance -fire -harvest -grazing -agriculture HR H2O H2O Allocation to New growth Snow Photosynthesis Plant C H2O Annual Input N Deposition N Fixation LAI N Uptake Litter Soil Total Respiration Soil Organic Matter Soil Mineral N Daily - Annual Allocation  Carbon, Nitrogen -leaf (LAI) -stem -coarse root -fine root C H2O Outflow Soil and Litter Respiration Atmospheric N H2O C C Flux N Flux

  6. BIOME-BGC Eco-physiological Parameters • Biome-BGC uses a list of 43parameters to differentiate biomes. • general eco-physiological characteristics • must be specified prior to each model • simulation • can be measured in the field, obtained from the • literature or derived from other measurements. Default Biome types with defined parameters • Deciduous Broadleaf Forest (temperate) • Deciduous Needleleaf forest (larch) • Evergreen Broadleaf Forest (subtropical/tropical) • Evergreen Needleleaf Forest • Evergreen Shrubland • C3 Grassland • C4 Grassland

  7. Surface weather database Vegetation parameter database Disturbance history database Other inputs: soils, elevation, N-deposition Landcover database Biome BGC Model Estimates of: Outflow LAI Rh Soil C Snow fPAR ET NEE NPP Biomass Hydrograph data Flux tower data Ancillary measurements at flux sites Satellite data (MODIS, AVHRR) SNOTEL data FIA, FHM, Ecodata (Inventory) Integration Simulation Validation

  8. BIOME-BGC Simulated Daily Carbon and Water Exchange (1Barrow Tussock / Wet Sedge Tundra Site, 2000) Daily 1Meteorology Daily C Budget 1 Daily meteorological data obtained from Barrow W Post Station, 71.28N 156.76W

  9. BIOME-BGC Simulated Cumulative Net Carbon Exchange (1Barrow Tussock / Wet Sedge Tundra Site) C sink (+) C source (-) 1 Daily meteorological data obtained from Barrow W Post Station, 71.28N 156.76W

  10. C source (+) Alaska Study Region C sink (+) C source (+) C sink (+) Biome-BGC runs for 4 areas in Alaska Site Name Latitude Kenai AK 60.18N Bonanza Creek AK 64.70N Coldfoot AK 67.15N Atigun AK 68.02N

  11. Biome-BGC Estimates of LAIPark Falls, WI

  12. Biome-BGC Estimates of NEE and GPP

  13. Suggested ImprovementstoBiome-BGCSimulations at ChEAS Flux Tower Sites

  14. Wetland-BGC • Presently being tested in Barrow, AK and the Niyak floodplain near Glacier Park, MT • Dynamic groundwater component • Previously 1 soil layer, now 2 (saturated/unsaturated) • Designed to be require minimal additional data • Methane??

  15. Natural Disturbances Timing Intensity Examples Fire Blowdown Managed Disturbances Timing Intensity Examples Fertilization Harvest Slash burn Plant Unique Site Disturbance History

  16. Temporal Necessary for historic disturbances 1 simulation for each year of the meteorological record Obscures effects of meteorology to allow recovery to be seen Spatial Non-interactive Age class Old growth forests Selective harvest and replant Vegetation Type ENF vs. DBF Hydrology Upland vs. wetland Ensembling of Simulations

  17. Disturbance History Credit: P. Thornton, NCAR

  18. Seasonal Cycle of GEP Credit: P. Thornton, NCAR

  19. Annual LAI in Final Simulation Year Credit: P. Thornton, NCAR

  20. Annual NEE in Final Simulation Year Credit: P. Thornton, NCAR

  21. Annual ET in Final Simulation Year Credit: P. Thornton, NCAR

  22. Suggested Improvements • Difficult to attribute discrepancies to either the model or measurements • Probably a combination of: • Site-specific parameterization • Low maximum stomatal conductance • Incorrect treatment of respiration at low Tair • Site-specific measurement biases • Undermeasurement of warm season respiration • Need to find a way to decompose NEE

  23. Biome-BGC Default Eco-physiological Parameters: Evergreen Needleleaf Forest

  24. MET_INPUT (keyword) start of meteorology file control block BIOME-BGC Example Initialization File metdata/TDE.mtc41 meteorology input filename 4 (int) header lines in met file RESTART (keyword) start of restart control block 1 (flag) 1 = read r estart file 0 = don't read restart file 0 (flag) 1 = write restart file 0 = don't write restart file 0 (flag) 1 = use restart metyear 0 = reset metyear restart/TDE_n.endpoint input restart filename restart/TDE. endpoint output restart filename TIME_DEFINE (keyword - do not remove) 8 (int) number of meteorological data years 8 (int) number of simulation years 1993 (int) first simulation year 0 (flag) 1 = spinup simulation 0 = normal simulation 6000 (int) maximum number of spinup years (if spinup simulation) CLIM_CHANGE (keyword - do not remove) 0.0 (deg C) offset for Tmax 0.0 (deg C) off set for Tmin 1.0 (DIM) multiplier for Prcp 1.0 (DIM) multiplier for VPD 1.0 (DIM) multiplier for shortwave radiation CO2_CONTROL (keyword - do not remove) 1 (flag) 0=constant 1=vary with fil e 2=constant, file for Ndep 356.0 (ppm) constant atmospheric CO2 concentration TDE_co2.txt (file) annual variable CO2 filename SITE (keyword) start of site physical constants block 0.765 (m) effective soil dept h (corrected for rock fraction) 28.0 (%) sand percentage by volume in rock - free soil 64.0 (%) silt percentage by volume in rock - free soil 8.0 (%) clay percentage by volume in rock - free soil 290.0 (m) site elevation 35.95 (degrees) site latitude ( - for S.Hem.) 0.2 (DIM) site shortwave albedo 0.0005 (kgN/m2/yr) wet+dry atmospheric deposition of N 0.0004 (kgN/m2/yr) symbiotic+asymbiotic fixation of N

  25. RAMP _NDEP (keyword - do not remove) 0 (flag) do a ramped N - deposition run? 0=no, 1=yes BIOME-BGC Example Initialization File (cont.) 2099 (int) reference year for industrial N deposition 0.0001 (kgN/m2/yr) industrial N deposition value EPC_FILE (keyword - do no t remove) dbf.epc (file) TDE DBF ecophysiological constants W_STATE (keyword) start of water state variable initialization block 0.0 (kg/m2) water stored in snowpack 0.5 (DIM) initial soil water as a proportion of sa turation C_STATE (keyword) start of carbon state variable initialization block 0.001 (kgC/m2) first - year maximum leaf carbon 0.0 (kgC/m2) first - year maximum stem carbon 0.0 (kgC/m2) coarse woody debris carbon 0. 0 (kgC/m2) litter carbon, labile pool 0.0 (kgC/m2) litter carbon, unshielded cellulose pool 0.0 (kgC/m2) litter carbon, shielded cellulose pool 0.0 (kgC/m2) litter carbon, lignin pool 0.0 (kgC/m2) soil carbon, fast microbial recycling pool 0.0 (kgC/m2) soil carbon, medium microbial recycling pool 0.0 (kgC/m2) soil carbon, slow microbial recycling pool 0.0 (kgC/m2) soil carbon, recalcitrant SOM (slowest) N_STA TE (keyword) start of nitrogen state variable initialization block 0.0 (kgN/m2) litter nitrogen, labile pool 0.0 (kgN/m2) soil nitrogen, mineral pool OUTPUT_CONTROL (keyword - do not remove) outputs/TDE_out (text) pr efix for output files 1 (flag) 1 = write daily output 0 = no daily output 0 (flag) 1 = monthly avg of daily variables 0 = no monthly avg 0 (flag) 1 = annual avg of daily variables 0 = no annual avg 1 (flag) 1 = write annual output 0 = no annual output 1 (flag) for on - screen progress indicator DAILY_OUTPUT (keyword) 3 (int) number of daily variables to output 516 0 epv.vwc (%) 43 1 wf.soilw_trans (kg m^ - 2) 38 2 wf.canopyw_evap (kg m^ - 2) ANNUAL_OUTPUT (keyword) 2 (int) number of annual output variables 545 0 annual maximum projected LAI 636 1 vegetation C END_INIT (keyword) indicates the end of the initialization file

  26. What if Some Met Data is Missing? • Use a nearby weather station • Use MT-CLIM to estimate radiation and humidity measurements from Tmax, Tmin • designed to handle complex terrain • uses a base station to calculate “site” data • Use DAYMET (conterminous U.S. only) • uses several met stations surrounding site • data available from 1980-1997 • takes into account complex terrain

  27. (MPa) (%) Soil Class Silt loam Silt Loam β-value -4.625 -3.84 -5.275 VWC_sat 0.48 0.48 0.41 PSI_sat -0.0073 -0.0078 -0.0013 BIOME-BGC 1Soil Water – Soil Water Potential Curves 1after Cosby et al., 1984

  28. BIOME-BGC Environmental Controls on Canopy Conductance (Walker Branch Site) M_total,sun,shade = (MPPFD,sun,shade * MTmin * MVPD * MPSI) where multipliers range from 0 (full Gs reduction) to 1 (no effect) Gs, sun,shade = Gs,max * M_total, sun,shade

  29. MODIS vs. Biome-BGC LAI

  30. GPP Estimates of 5X5 km Grid

  31. Park Falls/WLEF, WI

  32. Park Falls/WLEF, WI: Tower vs. DAO

  33. GPP from MOD17A2 Algorithm Default (DAO) Data As Input Meteorology

  34. GPP from MOD17A2 Algorithm Tower Data As Input Meteorology

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