Development of a comprehensive flash drought monitoring framework

During this project, we will develop a flash drought monitoring framework using various gridded datasets that together capture the multivariate nature of this high-impact climate phenomenon and its rapid evolution over sub-seasonal timescales. The proposed research includes three tasks that will lead to new insight into the characteristics of flash drought and enhance our ability to detect their onset, determine their severity, and monitor their compound and cascading impacts. First, we will develop a flash drought intensity index (FDII) that can be used to identify flash drought events and to categorize their severity. The development of an FDII is an important advancement for flash
drought monitoring and research because it will provide a more complete measure of flash drought severity than existing methods that focus only on their rate of intensification without considering the severity of the drought itself. The FDII method will then be applied to a set of atmospheric and land surface variables to develop a comprehensive and multivariate climatology of flash drought occurrence and severity across the U.S. The climatology will include variables depicting anomalies in precipitation, evaporative demand, soil moisture, evapotranspiration, and vegetation health that together capture the drivers and impacts of flash drought. Detailed analysis of the climatology will
provide valuable information regarding the timing and severity of flash drought in each dataset. The timing of rapid changes in each variable, whether those changes occur simultaneously or sequentially, and the severity of the drought conditions provide guidance regarding the compound and cascading impacts associated with flash drought. Results from these tasks will then inform
development of the multivariate flash drought monitor during the final part of the project.

The proposed project is directly relevant to the MAPP “New Climate Monitoring Approaches and
Products for Areas of Climate Risk” competition through the development of an experimental flash drought monitor that will provide a comprehensive assessment of the spatial extent and severity of these high-impact climate features using a multivariate monitoring framework. By using datasets
depicting anomalies in meteorological, soil moisture, and vegetation conditions, the flash drought monitor will be able to capture the multivariate linkages between the atmosphere and land surface components of the climate system and also be grounded in the physical drivers of variability and
change. Because flash drought is often accompanied by extreme temperatures and leads to rapid decreases in water resource availability, the proposed research will help address the monitoring needs for MAPP’s extreme heat and hydroclimate high priority climate risk areas. It will also directly benefit the Climate Prediction Center and the authors of the weekly U.S. Drought Monitor analyses through development of a framework that will enhance their ability to monitor the rapid evolution and severity of flash drought. Finally, the multivariate flash drought climatology and FDII monitoring framework will be valuable resources for the authors of the National Climate
Assessment because they will support the generation of regional assessments of projected changes in the occurrence, spatial extent, and severity of flash drought.