Diagnostic Classification of Flash Drought Events Reveals Distinct Classes of Forcings and Impacts

作者：Mahmoud Osman, Benjamin F. Zaitchik, Hamada S. Badr, Jason A. Otkin, Yafang Zhong, David J. Lorenz, Martha C. Anderson, Trevor F. Keenan, David L. Miller, Christopher Hain, Thomas Holmes · 发表于：Journal of Hydrometeorology · 年份：2022 · DOI：10.1175/jhm-d-21-0134.1 · 被引用次数：43 · 研究领域：Hydrology and Drought Analysis、Climate variability and models、Plant Water Relations and Carbon Dynamics

Abstract Recent years have seen growing appreciation that rapidly intensifying flash droughts are significant climate hazards with major economic and ecological impacts. This has motivated efforts to inventory, monitor, and forecast flash drought events. Here we consider the question of whether the term “flash drought” comprises multiple distinct classes of event, which would imply that understanding and forecasting flash droughts might require more than one framework. To do this, we first extend and evaluate a soil moisture volatility–based flash drought definition that we introduced in previous work and use it to inventory the onset dates and severity of flash droughts across the contiguous United States (CONUS) for the period 1979–2018. Using this inventory, we examine meteorological and land surface conditions associated with flash drought onset and recovery. These same meteorological and land surface conditions are then used to classify the flash droughts based on precursor conditions that may represent predictable drivers of the event. We find that distinct classes of flash drought can be diagnosed in the event inventory. Specifically, we describe three classes of flash drought: “dry and demanding” events for which antecedent evaporative demand is high and soil moisture is low, “evaporative” events with more modest antecedent evaporative demand and soil moisture anomalies, but positive antecedent evaporative anomalies, and “stealth” flash droughts, which are different f...