骤旱是一种以快速发展为主要特征的干旱。全球变暖背景下，近年来骤旱频发且不断加剧，严重影响我国农业生态系统和人类健康。了解骤旱事件的时空特征及其影响因素，对骤旱的监测、预警和防治至关重要。基于1981—2020年ERA5-LAND数据，辅以趋势分析和相关分析等气候诊断方法，对黄土高原生长季（4—9月）热浪型和缺水型骤旱的时空特征进行分析。结果表明：（1） 近40 a黄土高原2类骤旱呈波动增加趋势。其中，缺水型骤旱增加速率[0.54候·(10a)^-1]高于热浪型骤旱[0.46候·(10a)^-1]；年代变化上，黄土高原2类骤旱变化具有相似性。1998年之前，2类骤旱以低位波动为主；1998—2010年，骤旱迅速增加；2010年后，骤旱增速停滞且呈下降趋势。（2） 空间上，热浪型、缺水型骤旱分别有36.5%、37.5%的区域呈显著增加趋势（P<0.05）。黄土丘陵沟壑区、河套平原东部、汾渭河谷平原、黄土高原沟壑区东部，为2类骤旱共同显著增加区。（3） 在影响因素上，青藏高原北部气压、赤道印度洋中部（0°~10°N、50°~90°E区域）海温异常，与黄土高原生长季骤旱异常显著正相关，即青藏高原北部气压偏高，赤道印度洋中部海温异常偏高时，黄土高原2类骤旱发生风险均较高。

Flash drought is a type of drought characterized by rapid intensification. In the context of global warming, flash droughts are increasingly frequent, which has had a devastating impact on the agricultural ecosystem and public health of China. Understanding the spatiotemporal variation characteristics and influencing factors of flash drought events is of critical importance for monitoring, early warning, and loss prevention. On the basis of ERA5-Land data from 1981 to 2020, this study examined the spatiotemporal variation of two types of flash drought (heat wave and precipitation deficit flash drought) in the Loess Plateau using trend and correlation analyses. The relationship between the different atmosphere-ocean oscillation indices and the number of flash drought is also examined. The following results are presented. (1) The frequency of the two types of flash drought increased significantly from 1981 to 2020, with a higher increasing precipitation deficit rate [0.54 penta·(10a)^-1] than that of heat wave [0.46 penta·(10a)^-1] flash drought. Particularly, the two types of flash drought had a similar pattern in decadal variation. Before 1998, the two types of flash drought primarily displayed low fluctuation. From 1998 to 2010, the number of flash droughts rapidly increased. The growth rate of flash droughts stalled and began to decline after 2010. (2) A spatially significant (P<0.05) upward trend for heat wave (precipitation deficit) flash drought was observed in 36.5% (37.5%) of the Loess Plateau. The parts of the Loess Plateau with gullies and hills, as well as the eastern Hetao Plain and the Fenwei River Valley Plain, had a marked increase in the incidence of heat waves and precipitation deficit flash droughts. (3) Considering the influencing factors, the trend and interannual oscillations of flash drought in the Loess Plateau can be explained by the sea surface temperature (SST) anomaly in the NINO B region and the atmospheric pressure anomaly in the northern Qinghai-Tibet Plateau. The Loess Plateau had an increase in the probability of flash drought due to positive air pressure anomalies in the northern Qinghai-Tibet Plateau and large SST anomalies in the central equatorial India Ocean.