- 1California State University Los Angeles, Geography, Geology, and Environment, United States of America (afarahm2@calstatela.edu)
- 2Newcastle University, School of Engineering, Newcastle, United Kingdom
- 3Lamont-Doherty Earth Observatory, Palisades, United States
- 4University of California Los Angeles - JIFRESSE
- 5University of California, Irvine, Department of Civil and Environmental Engineering, Irvine, United States
- 6University of Florida, Department of Geography, Gainesville, United States
- 7San Jose State University, San Jose, United States
- 8Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
Flash droughts can develop suddenly, often within just a few weeks, and are marked by rapidly depleting soil moisture and intense heat stress. These conditions can have devastating effects on crop growth and disrupt entire ecosystems. What makes flash droughts especially challenging is their tendency to occur during the peak growing season, leaving little time for the agricultural and ecological sectors to prepare or mitigate losses. While a lack of precipitation is the primary trigger, other factors like high evaporative demand, low humidity, increased solar radiation, and clear skies can intensify their onset. Since flash droughts are driven by a combination of factors, it is crucial to rely on diverse and accurate data sources to effectively monitor their development and spread.
Previous studies have largely focused on analyzing the evolution of flash droughts using reanalysis data. However, there has been no comprehensive examination of their development at large scales incorporating a wide range of satellite observations. In this study, we characterized flash droughts over the Contiguous United States (CONUS) using remote sensing data from 2003 to 2020. We employed a unique combination of satellite climatic, agricultural, and ecological variables, including Atmospheric Infrared Sounder (AIRS) Vapor Pressure Deficit (VPD), Relative Humidity (RH), Temperature, ERA5 Soil Moisture, Global Precipitation Measurement (GPM) Precipitation, MODIS (Moderate Resolution Imaging Spectroradiometer) Evapotranspiration (ET), Potential Evapotranspiration (PET), Leaf Area Index (LAI), Normalized Difference Vegetation Index (NDVI), land cover map, and Orbiting Carbon Observatory-2 (OCO-2) Contiguous Solar-Induced Chlorophyll Fluorescence (CSIF). Flash drought events were identified based on root zone soil moisture (RZSM), with all variables aggregated into 8-day (octad) averages to analyze their temporal evolution and lead-lag correlations with RZSM.
Furthermore, the deteriorating impact of flash droughts associated with background aridity needs to be considered when monitoring their agricultural and ecological impacts. To address this, we investigated ecosystem responses to flash droughts across five climate regimes defined using the Aridity Index (AI) within the CONUS. We separated agricultural lands from natural vegetation to differentiate the development of flash droughts across these distinct ecosystems. Finally, we examined the propagation timeline of flash droughts from meteorological to agricultural and ecological droughts using cross-correlation and Cross Wavelet Transform methods.
How to cite: Farahmand, A., Zeraati, M., Seager, R., Madani, N., AghaKouchak, A., Wen, Y., Fowler, H., Mehran, A., and Parazoo, N.: Utilizing Satellite Data for Large-Scale Monitoring and Analysis of Flash Droughts Across the Contiguous United States , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13779, https://doi.org/10.5194/egusphere-egu25-13779, 2025.
