基于多源数据的长江流域1982—2022年骤旱事件时空演变

Temporal and spatial evolution of flash drought events in the Yangtze River basin from 1982 to 2022 based on multi-source data

  • 摘要: 骤发性干旱(简称骤旱)是一种突发性高且强度大的极端干旱现象, 会对农业生产和生态系统构成严重威胁。近年来, 长江流域骤旱频发, 然而其骤旱时空演变格局及规律尚不明晰。本研究基于GLEAM、GLDAS和ERA5-Land数据, 以标准化蒸发胁迫比及其变化值作为识别指标, 开展1982—2022年长江流域骤旱识别, 全面分析长江流域骤旱空间分布和时间演变特征; 并鉴于2022年旱情的严重性和特殊性, 重点分析该年长江流域骤旱事件。研究结果表明: ①在空间分布上, 长江流域上游的金沙江水系和中下游的大型水库湖泊骤旱发生频率最高且强度最大; ②在时间演变上, 骤旱发生频率、平均持续时间和强度均在长江流域整体上呈现出非显著上升趋势, 而有显著变化趋势的区域在2001年前后表现出明显的趋势反转现象; ③ 2022年夏季受极端高温热浪影响, 长江流域遭遇大规模骤旱事件, 具有波及范围广、持续时间长的特点, 且骤旱在空间上呈现出从上游向下游传递的态势。

     

    Abstract: A flash drought is an extreme drought phenomenon that has high suddenness and intensity and can pose a severe threat to agricultural production and ecosystems. In recent years, flash droughts have occurred frequently in the Yangtze River basin, but the temporal and spatial evolution characteristics of these flash droughts are still unclear. In this study, based on Global Land Evaporation Amsterdam Model (GLEAM), Global Land Data Assimilation System (GLDAS), and ERA5-Land data, the standardized evaporation stress ratio and changes in its value were used as identification indicators to identify flash drought events in the Yangtze River basin from 1982 to 2022, and comprehensively analyze their spatial distribution and temporal evolution characteristics. Additionally, the study examined the flash drought events in the Yangtze River basin in 2022 due to their severity and singularity. The results were as follows : ① In terms of spatial distribution, the Jinsha River in the upper reaches and the large reservoirs and lakes in the middle and lower reaches of the Yangtze River basin had the highest frequency and intensity of flash drought events. ② Temporally, the frequency, average duration, and intensity of flash drought events all showed an insignificant upward trend in the Yangtze River basin as a whole from 1982 to 2022, while some smaller areas with significant trends exhibited a notable trend reversal around 2001. ③ The Yangtze River basin was affected by extreme high temperatures and a heat wave in the summer of 2022 and suffered a large-scale flash drought event that was wide in scope, long in duration, and spatially propagated from upstream to downstream.

     

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