Modeling gross primary production of croplands and grasslands using MODIS images, climate data and the Vegetation Photosynthesis Model (VPM)
Xiangming
Xiao, University of Oklahoma, xiangming.xiao@ou.edu
(Presenting)
Joshua
Kalfas, University of Oklahoma, joshua.l.kalfas@ou.edu
Diana
Vanegas Beltran, University of Oklahoma, dianaxime@ou.edu
Akira
Miyata, National Institute for Agriculture and Environmental Study, Japan, amiyat@niaes.affrc.go.jp
Humin
Yan, Institute of Geographic Science and Natural Resources Research, Chinese Academy of Sciences, China, yanhm@igsnrr.ac.cn
Vegetation canopy can be partitioned into chlorophyll content and non-photosynthetic vegetation (NPV; e.g., cell walls, senescent leaf, trunks), and accordingly, the fraction of photosynthetically active radiation (PAR) absorbed by the vegetation canopy (FPARcanopy) can be partitioned into the fraction of light absorption by leaf chlorophyll (FPARchl) and by non-photosynthetic vegetation (FPARnpv). The Vegetation Photosynthesis Model (VPM) estimates FPARchl and calculates gross primary production (GPP) as a function of chlorophyll-based PAR absorption (FPARchl x PAR) and light use efficiency. The VPM model has been evaluated over various forest sites in the last few years. In this poster, we report simulation results of the VPM model for several sites of croplands (corn, soybean, winter wheat, and rice) and grasslands (C3 and C4 mixed grasslands). MODIS 8-day composites of Land Surface Reflectance are used to calculate the Enhanced Vegetation Index (EV), Land surface water index (LSWI), and Normalized Difference Vegetation Index (NDVI). GPP estimates from the VPM model agree well with GPP estimates from the CO2 eddy flux tower sites. The results from the VPM model simulations further demonstrate the potential of the VPM model for scale-up simulation of GPP and NPP from individual CO2 flux tower sites to the regional scale.
Presentation Type: Poster
Poster Session: Carbon Cycle Science
NASA TE Funded Awards Represented:
Xiao, Xiangming
Quantifying Leaf Chlorophyll Content, Light Absorption by Chlorophyll and Gross Primary Production