Drought Cascades in the Hydrologic Cycle: A Set of Case Studies from Remote Sensing

Droughts are catastrophic phenomena that result in shortages in food and water availability and billions of dollars of losses every year globally. Previous studies show that drought may be initialized in the atmosphere. However, it exhibits spectrum of changes in different land surface variables. With the evolution of remote sensing technologies, we have the ability to investigate this cascading phenomenon across multiple droughts in larger spatial scales. In this study, we use multiple NASA satellite data to look at the evolution of four largest historical United States droughts: 2012 Midwest flash drought, 2011 Texas drought, 2008-2010 southeast drought and 2012-2016 California drought. To achieve this, we have used Atmospheric Infrared Sounder (AIRS) Vapor Pressure Deficit (VPD), Climate Hazards Center InfraRed Precipitation with Station data (CHIRPS) Precipitation, Modern-Era Retrospective analysis for Research and Applications (MERRA) Soil Moisture and Gravity Recovery and Climate Experiment (GRACE) Terrestrial Water Storage (TWS). MERRA soil moisture information was selected due to the limitations in long term satellite-based soil moisture data. The results show that VPD can detect the drought onset in the rapidly evolving 2012 drought while precipitation is the drought onset indicator for other case studies. Furthermore, soil moisture drought signals are generally translated with delay and less severity from the precipitation and TWS drought signals with delay compared to soil moisture. This study highlights the importance of satellite observations in investigating the evolution of different types of drought across the United States.