ASCAT METOP-A Satellite Observations of Recent Drought Patterns over the USA: An Assessment of Spatial Extent and Relationship with Precipitation and Crop Yield

Abstract:

We analyzed 4-years of Advanced Scatterometer (ASCAT) incidence angle normalized C-band backscatter, NEXRAD precipitation and USDA crop yield data over the contiguous United States. Large negative anomalies in backscatter are evident over the U.S. during the 2011 and 2012 growing seasons. The backscatter anomalies were correlated with diminished growing season precipitation and with reduced crop yields reflecting where drought-related impacts on above-ground biomass production occurred. During periods of acute drought, differences in diurnal backscatter were reduced and in some cases reversed reflecting diminished nocturnal leave recovery. The results indicate that the C-band, VV-polarized ASCAT backscatter data is sensitive to interannual variability in agricultural productivity rather than soil moisture, and can offer an important geophysical monitoring tool capable of identifying drought-related vegetation responses independent of and complementary to satellite optical/near-infrared remote sensing data. This technique is flexible and adaptable, providing a capability to address region-specific needs. The twice-daily and near-real time global monitoring capabilities of ASCAT and similar microwave instruments can help improve California’s drought preparedness and mitigation planning allowing improved water resource management for agriculture on the local as well as the state level.