ARS | Publication request: MODIS EVI as a Proxy for Net Primary Production across Precipitation Regimes

Submitted to: American Geophysical Union
Publication Type: Abstract Only
Publication Acceptance Date: October 1, 2009
Publication Date: December 10, 2009
Citation: Bresloff, C., Moran, M.S., Huete, A., Huxman, T., Bosch, D.D., Bradford, Buda, A.R., Gunter, S.A., Mcnab, H., Mcclaran, M., Peters, D.C., Sadler, E.J., Seyfried, M.S., Sutherland Montoya, D. 2009. MODIS EVI as a Proxy for Net Primary Production across Precipitation Regimes. [abstract]. Amer. Geophysic Union Fall Meeting. San Francisco, CA. 14-18 December 2009.

Interpretive Summary: Above ground net primary production (ANPP) is a measure of the rate of photosynthesis in an ecosystem, and is indicative of its biomass productivity. Prior studies have reported a relationship between ANPP and annual precipitation which converged across biomes in dry years. This deserves further study over multiple biomes and precipitation patterns, but ANPP data distributed over space and time are difficult and costly to obtain. This study used a seasonally integrated EVI, Enhanced Vegetation Index, derived from the MODIS satellite, as a proxy for ANPP at 11 USDA Experimental Sites across the United States over the years 2001-2008. Care was taken to choose targets that represented a given biome at the 2 x 2 km scale of the EVI pixel and that were undisturbed over the 9-year study period. The relationship between integrated EVI and annual precipitation converged to a linear trend for all sites during the driest years in the study. A similar convergence was found for the wettest years. Our results support the use of the spatially and temporally distributed MODIS EVI as a proxy for ANPP measurements to study the productivity of vegetation across diverse biomes related to anticipated changes in precipitation.

Technical Abstract: Above ground net primary production (ANPP) is a measure of the rate of photosynthesis in an ecosystem, and is indicative of its biomass productivity. Prior studies have reported a relationship between ANPP and annual precipitation which converged across biomes in dry years. This deserves further study over multiple biomes and precipitation patterns, but ANPP data distributed over space and time are difficult and costly to obtain. This study used a seasonally integrated EVI, Enhanced Vegetation Index, derived from the MODIS satellite, as a proxy for ANPP at 11 USDA Experimental Sites across the United States over the years 2001-2008. Care was taken to choose targets that represented a given biome at the 2 x 2 km scale of the EVI pixel and that were undisturbed over the 9-year study period. The relationship between integrated EVI and annual precipitation converged to a linear trend for all sites during the driest years in the study. A similar convergence was found for the wettest years. Our results support the use of the spatially and temporally distributed MODIS EVI as a proxy for ANPP measurements to study the productivity of vegetation across diverse biomes related to anticipated changes in precipitation.