Interrelationship among among MODIS vegetation products across an Amazon Eco-climatic gradient

The Moderate Resolution Imaging Spectroradiometer (MODIS) has been found to be a useful tool in spatial and temporal terrestrial biosphere monitoring. In this study, we investigated the spatial and temporal interrelationships among MODIS vegetation products across a north-south Amazon eco-climatic transect, encompassing tropical forest, forestsavanna transition zone, and cerrado. MODIS vegetation index (VI), leaf area index (LAI), fraction of absorbed photosynthetically active radiation (FPAR), gross primary production (GPP), land surface water indices (i.e. LSWI) and land surface temperature (LST) products were extracted over both natural and converted areas along the climatic gradient. Our results showed strong spatial and temporal variations in vegetation dynamics over the climatic gradient with natural and converted areas responding differently. The relationships between VI and LAI/FPAR were unique with biome type. The VI and LSWI seasonal profiles matched fairly well in the cerrado region and conversion areas but not primary forest areas. A positive relationship was found between VI and LST in tropical forest, however the cerrado showed negative VI-LST relationships. These differences were related to the unique seasonal water and carbon patterns within each ecosystem. The interrelationships between MODIS land data products and land surface water indices yield important information useful in land cover characterization and prediction of vegetation responses to climate change and land cover conversions. Keywords-: MODIS, inter-relationship, Eco-climatic transect, Brazil, Amazon