Development and Validation of satellite-based Vegetation Photosynthesis Model
Abstract
Gross primary production (GPP) of vegetation is one of the key processes that determine net ecosystem exchange (NEE) of CO2 between the atmosphere and forest ecosystems. CO2 flux measurements at individual CO2 eddy flux sites provide valuable datasets for parameterization and validation of satellite-based diagnostic models. In this paper, we developed and validated the satellite-based Vegetation Photosynthesis Model (VPM) for modeling GPP, and applied it to a temperate deciduous broadleaf forest in the northeastern United States. VPM model estimates GPP of vegetation, using two improved vegetation indices (Enhanced Vegetation Index, Land Surface Water Index), temperature and photosynthetically active radiation (PAR) data. Three sets of simulations of the VPM model were conducted using input data from both the VEGETATION (VGT) and Moderate Resolution Imaging Spectroradiometer (MODIS) sensors. The first simulation used vegetation indices from 10-day composite VGT images and site-specific air temperature and PAR data from 4/1998 to 12/2001. The second simulation used vegetation indices from the 8-day MODIS Surface Reflectance Product, site-specific air temperature and PAR data in 2001. The third simulation used vegetation indices from the 8-day MODIS Surface Reflectance Product, land surface temperature from the 8-day MODIS Land Surface Temperature Product and site-specific PAR data in 2001. Predicted GPP values in the three simulations of VPM model agreed reasonably well with observed GPP of deciduous broadleaf forest in Harvard Forest, Massachusetts. This study highlighted the biophysical performance of improved vegetation indices in the context of GPP and demonstrated the potential of the VPM model for estimating GPP of deciduous broadleaf forests.
- Publication:
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AGU Spring Meeting Abstracts
- Pub Date:
- May 2004
- Bibcode:
- 2004AGUSM.B21B..05X
- Keywords:
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- 0400 Biogeosciences