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Arid Land Geography ›› 2023, Vol. 46 ›› Issue (3): 360-370.doi: 10.12118/j.issn.1000-6060.2022.307

• Climatology and Hydrology • Previous Articles     Next Articles

Spatiotemporal variation characteristics and influencing factors of heat wave and precipitation deficit flash drought in the Loess Plateau

REN Taotao(),LI Shuangshuang,DUAN Keqin(),HE Jinping   

  1. School of Geography and Tourism, Shaanxi Normal University, Xi’an 710119, Shaanxi, China
  • Received:2022-06-22 Revised:2022-08-23 Online:2023-03-25 Published:2023-03-31
  • Contact: Keqin DUAN E-mail:r1372841563@163.com;kqduan@snnu.edu.cn

Abstract:

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.

Key words: climate change, flash drought, spatiotemporal variation, ERA5-LAND, Loess Plateau