EGU General Assembly 2021
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Decomposing the Critical Components of Flash Drought Using the Standardized Evaporative Stress Ratio

Jeffrey Basara1,2, Stuart Edris1, Jordan Christian1, Bradley Illston3,1, Eric Hunt4, Jason Otkin5, and Scott Salesky1
Jeffrey Basara et al.
  • 1School of Meteorology, University of Oklahoma, Norman, OK, USA
  • 2School of Civil Engineering and Environmental Science, University of Oklahoma, Norman, OK, USA
  • 3Oklahoma Mesonet, University of Oklahoma, Norman, OK, USA
  • 4Atmospheric and Environmental Research, Inc., Lexington, MA, USA
  • 5Space Science and Engineering Center, Cooperative Institute for Meteorological Satellite Studies, University of Wisconsin-Madison, Madison, WI, USA

Flash droughts occur rapidly (~1 month timescale) and have produced significant ecological, agricultural, and socioeconomical impacts. Recent advances in our understanding of flash droughts have resulted in methods to identify and quantify flash drought events and overall occurrence. However, while it is generally understood that flash drought consists of two critical components including (1) anomalous, rapid intensification and (2) the subsequent occurrence of drought, little work has been done to quantify the spatial and temporal occurrence of the individual components, their frequency of covariability, and null events. Thus, this study utilized the standardized evaporative stress ratio (SESR) method of flash drought identification applied to the North American Regional Reanalysis NARR) to quantify individual components of flash drought from 1979 – 2019. Individual case studies were examined and the the drought component was assessed using the United States Drought Monitor for 2010 – 2019.   Additionally, the flash component was assessed using results of previous flash drought studies. Further, the correlation coefficient and composite mean difference was calculated between the flash component and flash droughts identified to determine what regions, if any, experienced rapid intensification but did not fall into flash drought. The results yielded that SESR was able to represent the spatial coverage of drought well for regions east of the Rocky Mountains, with mixed success regarding the intensity of the drought events. The flash component tended to agree well with other flash drought studies though some differences existed especially for areas west of the Rocky Mountains which experience rapid intensification at high frequencies but did not achieve drought designations due to hyper-aridity.

How to cite: Basara, J., Edris, S., Christian, J., Illston, B., Hunt, E., Otkin, J., and Salesky, S.: Decomposing the Critical Components of Flash Drought Using the Standardized Evaporative Stress Ratio, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-13683,, 2021.

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