Intensification of historical drought over China based on a multi-model drought index

摘要

Observations show that in recent decades, a large area of China has been affected by drought and that frequent droughts have caused damage to the ecological environment and the economy. Because of the differences in data and methods, assessing regional droughts often leads to contradictory conclusions of trending. The self-calibrated Palmer drought severity index (scPDSI) is based on multiple parameters, and it is considered regionally applicable and is widely used. However, some divergence has been observed in the results of drought in China using different scPDSI_PM (scPDSI based on the Penman-Monteith model) datasets. We establish an integrated scPDSI dataset (scPDSI_PM_INT) by averaging three scPDSI products and analyse the temporal change and spatial characteristics of drought in China from 1950 to 2009. The annual and seasonal drought intensities have increased slightly in the past 60 years, while the disturbed area has broadened significantly, especially in eastern China which has become much drier than before. The drought intensity of most drought-prone regions is slight and moderate, while severe and extreme droughts occur mostly in the Agro-Pastoral Transitional Zone and the Beijing-Tianjin-Hebei Region.