1. A FIRST LOOK AT THE MODIS 8-DAY PSN DATA FOR 2001 MODIS Science Team Mtg 19 December 2001 Steven W. Running NTSG, Univ. of Montana

3. MODIS Photosynthesis GPP = Radiation Use Efficiency Absorbed Photosynthetically Active Radiation x The Monteith equation….  APAR (FPAR) (0.45R net )

4. Photosynthesis Under Optimum Conditions Epsilon is the slope of the line described by GPP =  APAR MODIS Photosynthesis

5. Radiation Use Efficiency  =  max [m tmin ][m vpd ] Maximum Radiation Use Efficiency under ideal conditions for each biome Vapor Pressure Deficit Coefficient Temperature Coefficient for each biome The coefficients are calculated from daily minimum and maximum air temperature which are therefore necessary inputs to the model

6. Grassland Biome Tmin_max & Tmin_min are Tabulated by biome All Biomes Tmin_max Tmin_min VPDTmin VPD & Tmin Coefficients

7. ESTIMATION OF DAILY NPP IN MOD17 ALGORITHM

11. MODIS 8-day PSN Winter 2001

12. MODIS 8-DAY PSN SUMMER 2001

13. MODIS 8-day LAI Product LAI of center pixel Park Falls forest site 17MAY2001 – 16OCT2001 Park Falls forest site 17MAY2001 – 16OCT2001 The variability in LAI around the flux tower is shown by the scatter of blue (3x3 km) and green (5x5 km) dots. Park Falls 5x5 km Land Cover around tower Davis et al. Land Cover around tower Davis et al. LAI field data Co-Kriged Aug 2000 Gower et al. LAI field data Co-Kriged Aug 2000 Gower et al.

14. MODIS Cutouts: fPAR for Park Falls All pixels in 5x5 cutout Green=rejected Blue=accepted Accepted pixels

15. FLUXNET GRASSLAND SITES

16. FLUXNET FOREST SITES

17. SUMMARY 3 Sources of variability of MODIS PSN 1. Radiometric – MODIS FPAR and LAI 2. Meteorological – DAO IPAR and Temps 3. Ecological – MOD 17 representation of plant physiology Each require a different mode of validation