期刊
JOURNAL OF HYDROMETEOROLOGY
卷 21, 期 7, 页码 1513-1530出版社
AMER METEOROLOGICAL SOC
DOI: 10.1175/JHM-D-19-0290.1
关键词
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资金
- National Key Research and Development Program of China [2017YFA0603704]
- National Natural Science Foundation of China [41877159, 41605062]
- Open Foundation of State Key Laboratory of Hydrology Water Resources and Hydraulic Engineering [2016490211]
This study elucidates drought characteristics in China during 1980-2015 using two commonly used meteorological drought indices: standardized precipitation index (SPI) and standardized precipitation-evapotranspiration index (SPEI). The results show that SPEI characterizes an overall increase in drought severity, area, and frequency during 1998-2015 compared with those during 1980-97, mainly due to the increasing potential evapotranspiration. By contrast, SPI does not reveal this phenomenon since precipitation does not exhibit a significant change overall. We further identify individual drought events using the three-dimensional (i.e., longitude, latitude, and time) clustering algorithm and apply the severity-area-duration (SAD) method to examine the drought spatiotemporal dynamics. Compared to SPI, SPEI identifies a lower drought frequency but with larger total drought areas overall. Additionally, SPEI identifies a greater number of severe drought events but a smaller number of slight drought events than the SPI. Approximately 30% of SPI-detected drought grids are not identified as drought by SPEI, and 40% of SPEI-detected drought grids are not recognized as drought by SPI. Both indices can roughly capture the major drought events, but SPEI-detected drought events are overall more severe than SPI. From the SAD analysis, SPI tends to identify drought as more severe over small areas within 1 million km(2) and short durations less than 2 months, whereas SPEI tends to delineate drought as more severe across expansive areas larger than 3 million km(2) and periods longer than 3 months. Given the fact that potential evapotranspiration increases in a warming climate, this study suggests SPEI may be more suitable than SPI in monitoring droughts under climate change.
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