Characterizing the Spatial and Temporal Propagation Dynamics of Flash Droughts

Severe drought events have become more prevalent in recent decades. Over the past decade, there have been multiple notable drought events with rapid rates of intensification (i.e., flash drought) across different regions of the United States (U.S.). Moving towards prediction and mitigation of flash drought and its adverse effects requires an understanding how flash droughts evolve over time and move spatially through different areas of the U.S. To meet this end, we develop a framework that uses soil moisture anomalies to characterize the spatial and temporal propagation of flash drought. Specifically, we evaluate the spatiotemporal evolution of flash drought events that affected multiple regions of the United States (U.S.) from 2015 to 2018 using the NASA Soil Moisture Active Passive (SMAP) Level 3 soil moisture product. Anomalously wet and dry regions of the U.S. during this time period are mapped quantitatively via a composite of drought indices. One of these is a soil moisture index, which we will generate from downscaled SMAP data assimilated into the NASA Land Information System (LIS). We evaluate the indices at monthly time steps in order delineate the boundaries and centroids of flash drought events. Initial results show that this robust framework is general and can identify the boundaries and centroids of different flash drought event. This work has important implications for prediction of flash drought as it provides a foundation for understanding how and why these events evolve and intensify. This is crucial information for farmers and land managers who want to mitigate the adverse effects on humans, crop yields and natural ecosystem services.