关键词: 干旱, 时空变化, EOF/REOF分析, 小波分析, 中国

Abstract: Based on the data of monthly precipitation and monthly average temperature of 589 meteorological stations over China from 1961 to 2009, the spatial anomaly and temporal evolution characteristics of annual standard drought index are studied by using EOF, REOF, Wavelet analysis and Mann-Kendall test. Main results have been shown as follows. Abnormality of the annual standard drought index over China was significant in ten areas, just as Hetao northern China, middle and lower reaches of Yangtze River, southern China, main part of northeast China, southern Shaanxi eastern Qinghai, Yunnan-Guizhou-Guangxi hilly area, northern Xinjiang, western Sichuan eastern Tibet Plateau, eastern Liaoning, and Shandong northeastern Henan. Among them, the climate became significantly dryer in seven regions and it became significantly wetter in 3 regions. The most significantly drying region was Yunnan-Guizhou-Guangxi hilly area and the most significantly wetting region was northern Xinjiang. The abrupt change took place in 1980 in Yunnan-Guizhou-Guangxi hilly area, and the abrupt change also took place in 1980 in northern Xinjiang for arid-wet change. There existed multiple time scale features over China for arid-wet change according to wavelet energy spectrum, and the fluctuation period of 2~4 years was the most significant. The main period was 3 years over China, and there were main periods of 22 years and 8 years in southern Shaanxi eastern Qinghai for arid-wet change.

Key words: drought, spatiotemporal change, EOF/REOF analysis, wavelet analysis, China