ABSTRACT
The drought of 2012 in North America devastated agricultural crops and pastures, damaged agriculture and livestock industries, and eventually led to great losses in the economy. In this study, the drought maps of the U.S. Drought Monitor (USDM) and various drought-monitoring techniques based on the products from Earth-Observing satellite instruments such as the Gravity Recovery and Climate Experiment (GRACE) and the Moderate Resolution Imaging Spectroradiometer (MODIS) were intercompared for the 2012 drought in the southeastern United States. The results indicated that the spatial extent of drought reported by the USDM was in good agreement with that reported by the MODIS-based drought maps. The GRACE-based drought maps suggested that the southeastern United States experienced widespread decline in surface and root-zone soil moisture and groundwater resources. Disagreements among all drought indicators were observed over irrigated areas, especially in the Lower Mississippi region, where agriculture is mainly irrigated. We demonstrated that time lag of vegetation response to changes in soil moisture also partly contributed to these disagreements.
