1. Ensemble Ecosystem Model Experiment and Intercomparison using the Terrestrial Observation and Prediction System (TOPS)
Weile Wang, Jennifer L. Dungan, Andrew Michaelis, Hirofumi Hashimoto, Ichii Kazuhito, Ramakrishna Nemani

2. Ecosystem Models
Name
Genre
GPP
NPP
NEE/HR
Spin-up
Reference
Biome_BGC
Prog.
Far-quhar
GPP – AR
NPP – HR; HR estimated from soil pools;
Until equilibrium is reached
Thornton, et al. (2002)
LPJ
1000 climate years
Sitch et al. (2003)
CASA
Diag.
2*NPP
LUE
2000 climate years
Potter et al. (1993)
Flex-BGC
0.5*GPP
NPP-HR; HR estimated from base rate
N/A
Nemani et al. (in press)
Models are run for the NACP domain at 8km grids for the period using the Terrestrial Observation and Prediction System (TOPS)
Standard model outputs include GPP, NPP, NEE, ET, and soil moisture

3. Model inputs Climate Data :
Daily maximum/minimum temperature and precipitation extrapolated from the NCDC Cooperative Summary of the Day data (TD3200) for the period ;
Dew-point temperatures, vapor pressure deficit, and incident solar radiation generated based on algorithms described in Campbell and Norman (1998) and Jolly et al. (2005);
Satellite Data:
AVHRR/MODIS monthly LAI/FPAR ( );
MODIS 12Q1 land cover map;
Soil Data:
Soil texture and effective depth from ECOCLIMAP (Masson et al., 2003).

4. Temperature-Precipitation Space
Carbon Fluxes in T-P Space
Carbon Fluxes (GPP, NPP, and NEE)
Temperature

5. Results: GPP
FLEX-BGC

6. Results: NPP
FLEX-BGC

7. Results: NEE
FLEX-BGC

8. Conclusions
Annual total NPP for North America is estimated to be ~ PgC/yr and the overall NPP/GPP ratio of both BGC and LPJ is about 0.50
Patterns of NPP generally follow those of GPP (BGC and LPJ), however, remarkable differences are found in some regions (e.g., LPJ)
Substantial diversity is shown in NEE results: BGC and CASA are essentially carbon neutral; the total NEE estimated by LPJ and Flex-BGC is 0.47 PgC/yr and 1.29 PgC/yr, respectively (positive values indicate carbon sink)