Global Flash Drought Analysis: Uncertainties From Indicators and Datasets
Global Flash Drought Analysis: Uncertainties From Indicators and Datasets
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DOI：
10.1029/2022ef002660
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发表时间：
2022-06
期刊：
影响因子：
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通讯作者：
S. Mukherjee;Anshuman Mishra
中科院分区：
文献类型：
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作者：
S. Mukherjee;Anshuman Mishra
近年来，闪电干旱（FD）引起了人们的广泛关注，用于识别这些迅速加剧的事件的指标取得了重大进展。然而，现有的FD定义和方法的研究界和不同的数据源的选择之间的差异强调了解决与全球FD特征及其驱动因素相关的不确定性的重要性。本研究比较了基于蒸发应力比（ESR）和根区土壤水分（RZSM）得出的两个关键FD指标，使用三个不同的数据源来研究全球FD频率和强度（速度）的不确定性，以及影响因素。结果表明，这种差异是显着的两个FD指标在不同的气候区域的地球仪。结果突出了不同的空间驱动FD频率，强度，及其演变，可能与背景干旱。降水、温度、蒸汽压亏损和土壤温度耦合的变化对基于RZSM（ESR）的FD演变具有级联（并发）影响。ESR和RZSM之间的关系无法解释这些指标中的每一个特定的FD事件，特别是在过渡和潮湿的气候制度的方差。总的来说，研究结果强调了更细致入微的方法来获得FD指标的必要性，这些指标可以有效地将深层土壤水分快速消耗率与大气蒸发需求的变化相结合，这对植被健康有直接影响。
Flash Drought (FD) has garnered much attention in recent years, with significant advancements in the indicators applied for identifying these rapidly intensifying events. However, the difference in existing FD definitions and methodologies among research communities and the choice of different data sources underscores the importance of addressing the uncertainties associated with the global FD characteristics and their drivers. This study compares two key FD indicators derived based on evaporative stress ratio (ESR) and root‐zone soil‐moisture (RZSM) using three different data sources to investigate the uncertainties in global FD frequency and intensity (speed), and the influencing drivers. The results suggest that such disparities are significant in the two FD indicators across different climate regions of the globe. The results highlight varying spatial drivers of FD frequency, intensity, and their evolution, potentially linked to background aridity. Changes in precipitation, temperature, vapor pressure deficit, and soil‐temperature coupling play an important role with a cascading (concurrent) impact on the evolution of FD based on RZSM (ESR). The relationship between ESR and RZSM fails to explain most of the variance in each of these indicators specific to the FD episodes, especially in the transitional and humid climate regimes. Overall, the results highlight the necessity of more nuanced methodologies for deriving FD indicators that can efficiently couple the rapid soil‐moisture depletion rates in deeper layers with changes in atmospheric evaporative demand which has direct implications on vegetation health.