Soil moisture recognition and the spatial distribution of storm activity in the Mojave Desert using high-resolution ASTER and MODIS imagery for thermophysical mapping

Climate models suggest that the Mojave Desert ecoregion is vulnerable to becoming drier in the future, and as the human population grows and development increases, environmental stresses will likely increase. Determining the spatial distribution and variation of soil moisture on a regional scale is an essential component to climate change, hydrologic, and habitat analyses. Soil permeability and sediment stability are characteristics that have been shown to be measurable from remote sensing observations. The primary objective of this project is to map the mechanical composition of the surface materials in the Mojave Desert ecoregion with implications for soil permeability, sediment stability, and soil moisture. We are using advanced mapping techniques to determine the surface mechanical compositions of the Mojave, with data provided by the Advanced Spaceborne Thermal Emission and Reflection radiometer (ASTER), which provides the spatial resolution necessary to map the composition and thermal properties of arid surfaces and is well suited for mapping the spatial distribution of soil moisture. A full-resolution mosaic of thermal infrared (TIR) and visible to near infrared (VNIR) ASTER images has been constructed for the entire Mojave Desert for mapping surface components. With a 16-day repeat cycle, ASTER provides the high resolution mapping perspective, but lacks the temporal sampling to adequately quantify changes over days to weeks. Moderate Resolution Imaging Spectroradiometer (MODIS) data provides the temporal resolution needed to determine seasonal variations, although at a coarser spatial resolution. Our approach for mapping the Mojave Desert region involves using both ASTER and MODIS to provide the ideal spatial and temporal sampling to map individual storms and their effects on the seasonal conditions of the surface. The viability of the Mojave Desert ecosystem relies solely on infrequent storms and their temporal and spatial distribution over local regions and varied landscapes. Mapping the distribution of individual wetting events with regard to the geomorphology of the region can be a useful component for modeling potential changes as a function of climate change and human development providing a better understand of how random weather events contribute to the hydrologic cycle in the Mojave and potentially other arid regions around the world.