Synergistic use of AMSR-E and MODIS Data for Understanding Grassland Land Surface Phenologies

In recent investigations into the response of native grasslands to global environmental changes, rainfall variability has been offered as a key factor for explaining ecosystem structure and function. In particular, changes in the temporal patterns of precipitation were shown to alter critical aspects of the carbon cycle. To understand the impact of rainfall variability in grasslands, an understanding of the dynamics of surface moisture is critical. Here we characterize spatio-temporal patterns of two standard data products from AMSR-E: vegetation water content and surficial soil moisture. In addition, we explore the sensitivity of these products to an extreme precipitation event as modulated by land cover type. The sensitivities of vegetation water content and soil moisture retrievals were found to be dependent on the NDVI value, with an apparent loss of sensitivity at higher NDVI values. Despite the coarse spatial resolution of the data, the difference in between predawn and afternoon vegetation water content was found to be a potentially source of information about canopy water stress.