关键词: 气候暖干化, 气温, 降水, 旱涝灾害, 时空分布, 黄土高原

Abstract: In this paper, the spatiotemporal evolutions of annual precipitation, drought and flood were researched using the Kriging interpolation, Mann-Kendall test and Morlet wavelet analysis based on the annual precipitation data observed by 58 meteorological stations in the Loess Plateau during the period from 1960 to 2010 and the background of climate change and peculiar geographic location in China. The results revealed that the annual temperature in the Loess Plateau was increased, but the annual precipitation was decreased in the whole area and the semiarid and semihumid regions. Precipitation variation was the highest in arid zone but the lowest in semihumid regions. There was a regional difference of annual precipitation, the annual precipitation was gradually decreased from the southeast to the northwest, and drought trend became more obvious. The sharp change of mean annual temperature and precipitation occurred in 1996 and 1990 respectively. The drought and flood levels were in an increase trend, especially in the semihumid regions. Occurring frequencies of drought and flood were the highest in arid zone. Drought occurred more easily than flood, and the centers with high drought occurring frequency were dispersed; the occurring frequency of flood was the lowest in the west but the highest in the central area. There were the fluctuation periodicities of drought and flood in the Loess Plateau, the 25-30year fluctuation was the strongest, and it was considered that the current flood period would be ended, but a new drought period would begin.

Key words: climate drying-warming, air temperature, precipitation, drought and flood disasters, spatiotemporal distribution, the Loess Plateau