Faith Ann Heinsch1, John Kimball2, and Steve Running1

1Numerical Terradynamic Simulation Group2 Flathead Lake Biological Station

University of Montana

Biome-BGC and Estimations of Biome-BGC and Estimations of Tower FluxesTower Fluxes

Chequamegon Ecosystem-Atmosphere StudyAugust 16-21, 2002

MODIS NPP CalculationMODIS NPP Calculation

NPP (Net Primary Production)

• Quantifies vegetation growth

• Uses:– component of NEP for terrestrial carbon

source/sink analyses [global interest]– practical measure of crop/range/forest

growth [local interest]

MOD17:MOD17:The MODIS PSN/NPPThe MODIS PSN/NPP

AlgorithmAlgorithm

MODIS ProductivityMODIS Productivity

Design Limitations….

• Based on Remotely-Sensed LAI estimate

• 1 km2 resolution (possibly 250 m2) • Accuracy of supplemental inputs

– Vegetation Classification– Weather & Radiation Data

• Lack of growth respiration in weekly productivity

MODIS ProductivityMODIS Productivity

Design Limitations imply that...

• Can provide accurate large scale depictions of relative differences in productivity

• Accuracy of estimates at smaller scale will be subject to the accuracy of the vegetation classification and weather & radiation data

Remote Sensing of VegetationRemote Sensing of Vegetation

Satel

lite

PhotosyntheticallyActive Radiation

Ground

LeafLeaf

Leaf

LeafLeaf

Leaf

Signal Related to1. Leaf area2. Canopy structure3. Viewing angle

(PAR=0.45Rnet )

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

NDVI

LA

I

Grasslands and Cereal CropsMODIS MOD15 Back-up Algorithm

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

NDVI

FP

AR

Leaf Area Index (LAI)Leaf Area Index (LAI)

Fraction of Absorbed Fraction of Absorbed Photosynthetically Active Photosynthetically Active

Radiation (FPAR)Radiation (FPAR)

NDVINDVI

CanopyStructure

Vegetation Productivity

Algorithm

Weekly&

AnnualProductivity

MODIS ProductivityMODIS ProductivityData FlowData Flow

Temperature&

Radiation

VegetationType

VegetationCover

Algorithm

Leaf Area Index (LAI) Fraction of Radiation Absorbed (FPAR)

MODIS Instrument

1 km2 Reflectance Data

Vegetation ProductivityVegetation Productivity

GrossPhotosynthesis

RespirationNet PrimaryProductivity

(g C/m2) = -NPP GPP R

MODIS PhotosynthesisMODIS Photosynthesis

GPP = Radiation

UseEfficiency

AbsorbedPhotosynthetically

ActiveRadiation

x

The Monteith equation….The Monteith equation….

APAR

(FPAR) (0.45Rnet )

Radiation Use EfficiencyRadiation Use Efficiency

= max [mtmin ][mvpd ]

MaximumRadiation Use Efficiency

under ideal conditionsfor each biome

Vapor Pressure DeficitCoefficient

Temperature Coefficient for each biome

The coefficients are calculated from (DAO 1° resolution) daily minimum and maximum air temperature inputs

MODIS ProductivityMODIS Productivity

Annual = (Weekly) - R m_live wood - R g

Weekly = GPP - R m_leaf - R m_fine root

max (mtmin)(mvpd) (FPAR)(0.45Rnet )GPP =

Fractional veg coverSoils

Daily w eather data

Biome-BGCGPP, NPP, gs, etc

LAI / fPAR

Translation codeDaily w eather

data

Biome PropertiesLook-up Table

(BPLUT)

MOD-17LAI / fPARLandcover

DAO daily surface w eather

Daily NPPAnnual NPP

Biome-BGC MOD-17

AlgorithmC alibration

USE OF BIOME-BGC IN DERIVING THE MOD17BIOME PROPERTIES LOOK-UP TABLE

Algorithm ImplementationAlgorithm Implementation

Table 5.x Biome properties lookup table (BPLUT) Schema Field Description Units Biome Biome class code {1..14} N/a Epsilon_max Maximum theoretical light use

efficiency kg C/MJ PAR / m2 /day

Tmin_min Lowest minimum daily temperature C Tmin_max Highest minimum daily temperature C VPD_max Highest daily vapor pressure deficit Pa VPD_min Lowest daily vapor pressure deficit Pa SLA Specific leaf area leaf area / kg

leaf C Q10_mr Q10 maintenance respiration factor Kg C Froot_leaf_ratio Fine root leaf ratio unitless Livewood_leaf_ratio Live wood leaf ratio unitless Leaf_mr_base Leaf maintenance respiration base

value Kg C

Froot_mr_base Fine root maintenance respiration base value

Kg C

Livewood_mr_base Live wood maintenance respiration base value

Kg C

Leaf_gr_base Leaf growth base value Kg C Froot_leaf_gr_ratio Fine root to leaf growth ratio unitless Livewood_leaf_gr_ratio Live wood to leaf growth ratio unitless

Entries in the Biome Look-Up TableEntries in the Biome Look-Up Table

UMD vegetation classParameter name 1 2 3 4 5 6 7 8 9 10 11

epsilon_max 0.001008 0.001259 0.001103 0.001044 0.001116 0.000864 0.000768 0.000888 0.000774 0.000604 0.000604tmin_max 8.31 9.09 10.44 7.94 8.50 10.24 11.39 8.61 8.80 12.02 12.02tmin_min -8.00 -8.00 -8.00 -8.00 -8.00 -8.00 -8.00 -8.00 -8.00 -8.00 -8.00vpd_max 4100 4100 4100 4100 4100 4100 4100 4100 4100 4100 4100vpd_min 930 930 930 930 930 930 930 930 930 930 930sla 22.1 17.3 30.0 26.2 21.5 33.8 39.8 12.0 28.5 45.0 45.0q10_mr 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0froot_leaf_ratio 1.3 1.1 1.3 1.1 1.1 1.5 1.8 1.0 1.5 2.0 2.0livewood_leaf_rat 0.081 0.162 0.152 0.203 0.132 0.107 0.051 0.079 0.040 0.000 0.000leaf_mr_base 0.00653 0.00604 0.00805 0.00778 0.00677 0.00824 0.00869 0.00519 0.00714 0.00908 0.00908froot_mr_base 0.00519 0.00519 0.00519 0.00519 0.00519 0.00519 0.00519 0.00519 0.00519 0.00519 0.00519livewood_mr_base 0.00322 0.00397 0.00297 0.00371 0.00372 0.00212 0.00100 0.00436 0.00218 0.00000 0.00000leaf_gr_base 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3froot_leaf_gr_rati 1.3 1.1 1.3 1.1 1.1 1.5 1.8 1.0 1.5 2.0 2.0livewood_leaf_gr_r 0.16 0.20 0.15 0.19 0.19 0.11 0.05 0.22 0.11 0.0 0.0deadwood_leaf_gr_r 1.6 1.1 1.5 1.6 1.8 1.0 0.5 0.0 0.0 0.0 0.0

BIOME LOOK-UP TABLE FOR MOD17 ALGORITHM

maxTmin, VPD fPAR, Rnet GPP

LAI SLA

fine rootmass

allometry

leaf mass

Q10, Tavg MR

-

Daily"NPP"

=

MRindex

MOD-17Daily "NPP"

Photosynthesis

Maintenance Respiration

does not include grow th respiration orlive w ood maintenance respiration costs

leafmass

D aily O utputs

Estimation of Daily NPP in the MOD17 AlgorithmEstimation of Daily NPP in the MOD17 Algorithm

Leafm ass

M Rindex

Daily"NPP"

m ax

Annual sumDaily "NPP"

Annual sumM R index

allom etryAnnual averagelive wood m ass

M R scalarAnnual sum

live wood M R

leaflongevity

Annualleaf growth

allom etryAnnual

fine root andwood growth

GR scalarAnnual sum

GR

AnnualNPP

-

-

=

Annual m axleaf m ass

MOD-17Annual NPP

MOD-17 Daily Outputs

Annual Net Primary Production EstimationAnnual Net Primary Production Estimation

Biome-BGCBiome-BGC

BIOME-BGC estimates fluxes and storage of energy, water, carbon, and nitrogen for the vegetation and soil components of terrestrial ecosystems.

Model algorithms represent physical and biological processes that control fluxes of energy and mass:

• New leaf growth and old leaf litterfall • 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

The model uses a daily time-step with daily updating of vegetation, litter, and soil components.

The BIOME-BGC Terrestrial Ecosystem Process Model

• 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)

Major Features:

BIOME-BGC

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)

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

BIOME-BGC Eco-physiological Parameters

Biome-BGC uses a list of 43 parameters to differentiate biomes. These parameters define the general eco-physiological characteristics of the dominant vegetation type and must be specified prior to each model simulation. These parameters 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

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

value units description 1 (flag) 1 = WOODY 0 = NON-WOODY 1 (flag) 1 = EVERGREEN 0 = DECIDUOUS 1 (flag) 1 = C3 PSN 0 = C4 PSN 1 (flag) 1 = MODEL PHENOLOGY 0 = USER-SPECIFIED --- (yday) yearday to start new growth (when phenology flag = 0) --- (yday) yearday to end litterfall (when phenology flag = 0) 0.2 (prop.) transfer growth period as fraction of growing season 0.2 (prop.) litterfall as fraction of growing season 0.26 (1/yr) annual leaf and fine root turnover fraction 0.7 (1/yr) annual live wood turnover fraction 0.005 (1/yr) annual whole-plant mortality fraction 0.005 (1/yr) annual fire mortality fraction 1.4 (ratio) (ALLOCATION) new fine root C : new leaf C 2.2 (ratio) (ALLOCATION) new stem C : new leaf C 0.071 (ratio) (ALLOCATION) new live wood C : new total wood C 0.29 (ratio) (ALLOCATION) new croot C : new stem C 0.5 (prop.) (ALLOCATION) current growth proportion 42.0 (kgC/kgN) C:N of leaves 93.0 (kgC/kgN) C:N of leaf litter, after retranslocation 58.0 (kgC/kgN) C:N of fine roots 50.0 (kgC/kgN) C:N of live wood 730.0 (kgC/kgN) C:N of dead wood 0.31 (DIM) leaf litter labile proportion 0.45 (DIM) leaf litter cellulose proportion 0.24 (DIM) leaf litter lignin proportion 0.34 (DIM) fine root labile proportion 0.44 (DIM) fine root cellulose proportion 0.22 (DIM) fine root lignin proportion 0.71 (DIM) dead wood cellulose proportion 0.29 (DIM) dead wood lignin proportion 0.01 (1/LAI/d) canopy water interception coefficient 0.51 (DIM) canopy light extinction coefficient 2.6 (DIM) all-sided to projected leaf area ratio 8.2 (m2/kgC) canopy average specific leaf area (projected area basis) 2.0 (DIM) ratio of shaded SLA to sunlit SLA 0.033 (DIM) fraction of leaf N in Rubisco 0.004 (m/s) maximum stomatal conductance (projected area basis)

0.00004(m/s) cuticular conductance (projected area basis)

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

M_TMIN

0

0.2

0.4

0.6

0.8

1

-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1

TMIN (degC)

M_VPD

0

0.2

0.4

0.6

0.8

1

900 1200 15001800 2100 24002700 3000 33003600 39004200

VPD (Pa)

M_PPFD

0

0.2

0.4

0.6

0.8

1

0 150 300 450 600 750 900 10501200135015001650

PPFD (umol/m2/s)

M_PSI

0

0.2

0.4

0.6

0.8

1

-0.5 -0.7 -0.8 -1 -1.1 -1.3 -1.4 -1.6 -1.7 -1.9 -2 -2.2 -2.3

PSI (MPa)

MET_INPUT (keyword) start of meteorology file control block metdata/TDE.mtc41 meteorology input filename 4 (int) header lines in met file RESTART (keyword) start of restart control block 1 (flag) 1 = read restart 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) offset 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 file 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 depth (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

BIOME-BGCExample InitializationFile

RAMP_NDEP (keyword - do not remove) 0 (flag) do a ramped N-deposition run? 0=no, 1=yes 2099 (int) reference year for industrial N deposition 0.0001 (kgN/m2/yr) industrial N deposition value EPC_FILE (keyword - do not 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 saturation 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_STATE (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) prefix 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

BIOME-BGCExample Initialization File (cont.)

-5

-4.5

-4

-3.5

-3

-2.5

-2

-1.5

-1

-0.5

0

0 10 20 30 40 50

soilw

PS

I

-5

-4.5

-4

-3.5

-3

-2.5

-2

-1.5

-1

-0.5

0

0 10 20 30 40 50

soilw

PS

I

-5

-4.5

-4

-3.5

-3

-2.5

-2

-1.5

-1

-0.5

0

0 10 20 30 40 50

soilw

PS

I

(%)

(MP

a)

Soil Class Silt loam Silt Loamβ-value -4.625 -3.84 -5.275VWC_sat 0.48 0.48 0.41PSI_sat -0.0073 -0.0078 -0.0013

BIOME-BGC 1Soil Water – Soil Water Potential Curves

1after Cosby et al., 1984

BIOME-BGC Simulated Daily Carbon and Water Exchange(1Barrow Tussock / Wet Sedge Tundra Site, 2000)

Daily C BudgetDaily 1Meteorology

1 Daily meteorological data obtained from Barrow W Post Station, 71.28N 156.76W

-15

-10

-5

0

5

10

15

deg

C

0

50

100

150

200

250

300

cmTav Tsoil (Biome-BGC) Snow_z

-0.0020

-0.0010

0.0000

0.0010

0.0020

0.0030

0.0040

0.0050

0.0060

1/11/21

2/103/1

3/214/10

4/305/20

6/96/29

7/198/8

8/289/17

10/710/27

11/1612/6

12/26

kg C

m-2

day

-1

NEE GPP R_autotrophic R_heterotrophic

-50

-40

-30

-20

-10

0

10

20

30

1/12/1

3/14/1

5/16/1

7/18/1

9/110/1

11/112/1

g C

m-2

1996 1997 1999 2000 2001

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

2000 BIOME-BGC Cumulative Net C exchange(Boreal ENF Forest)

-250

-200

-150

-100

-50

0

50

100

150

200

250

Date

g C

m-2

Bonanza Creek Kenai Coldfoot Atigun

2001 BIOME-BGC Cumulative Net C exchange(Boreal ENF Forest)

-250

-200

-150

-100

-50

0

50

100

150

200

250

Date

g C

m-2

Bonanza Creek Kenai Coldfoot Atigun

C source (+)

C sink (+)

C source (+)

C sink (+)Alaska Study Region

Site Name LatitudeKenai AK 60.18NBonanza Creek AK 64.7NColdfoot AK 67.15NAtigun AK 68.02N

Biome-BGC runsfor 4 areas in Alaska

MODIS vs. Biome-BGC LAI

MODIS LAI vs BIOME BGC LAI Walker Branch, TN 2001 (Mixed Deciduous Hardwood Forest)

0

1

2

3

4

5

6

7

1 31 61 91 121 151 181 211 241 271 301 331 361

DOY

LA

I (m

2/m

2)

MODIS LAI BGC Proj LAI

Biome-BGC Estimates of LAIPark Falls, WI

Biome-BGC Estimate of NPP for Park Falls, 2001Maximum LAI = 3.2

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0 30 60 90 120 150 180 210 240 270 300 330 360

Day of Year

NP

P (

gC

m-2

d-1

)

Biome-BGC Estimate of NPP for Park Falls, 2002Maximum LAI = 3.3

0.00.51.01.52.02.53.03.54.0

0 30 60 90 120 150 180 210 240 270 300 330 360

Day of Year

NP

P (

gC

m-2

d-1

)

Biome-BGC Estimates of NPPPark Falls, WI

Biome-BGC Estimate of NPP for Park Falls, 2002

-1

0

1

2

3

4

5

6

7

0 30 60 90 120 150 180 210 240 270 300 330 360

Day of Year

NP

P (

gC

m-2

d-1

)

Biome-BGC Estimate of NPP for Park Falls, 2001

-1

0

1

2

3

4

5

0 30 60 90 120 150 180 210 240 270 300 330 360

Day of Year

NP

P (

gC

m-2

d-1

)

Biome-BGC Estimates of GPP Park Falls, WI

Biome-BGC Estimate of GPP for Park Falls, 2001

0

2

4

6

8

0 30 60 90 120 150 180 210 240 270 300 330 360

Day of Year

GP

P (

gC

m-2

d-1

)

Biome-BGC Estimate of GPP for Park Falls, 2002

0

2

4

6

8

10

0 30 60 90 120 150 180 210 240 270 300 330 360

Day of Year

GP

P (

gC

m-2

d-1

)

Comparing Biome-BGC withTower Flux Data

Verification of BIOME-BGC Daily and Seasonal Dynamics: Comparisons with Tower Eddy-flux Measurements

0

0.5

1

1.5

2

2.5

3

3.5

4

Date

mm

d-1

Tower Flux BIOME-BGC

-0.01

-0.005

0

0.005

0.01

Jan-94

Mar-94

May-94

Jul-94

Sep-94

Nov-94

Jan-95

Mar-95

May-95

Jul-95

Sep-95

Nov-95

Jan-96

Mar-96

May-96

Jul-96

Sep-96

Nov-96

Date

Kg

C m

-2 d

-1

BIOME-BGC Tower Flux

Mature Black Spruce Stand (NSA-OBS Ameriflux site) Mature Aspen Stand (SSA-OA BERMS site)

NEPNEP

ET ET

0

0.5

1

1.5

2

2.5

3

3.5

Date

mm

d-1

BIOME-BGC Tower Flux

-0.004

-0.003

-0.002

-0.001

0

0.001

0.002

0.003

0.004

Date

kg C

m-2

d-1

BIOME-BGC Tower Flux

Kimball et al., 1997a,b