关键词: 全球变暖, 西北干旱区, 降水, 未来趋势, global warming, Northwest China arid region, precipitation, future trend

Abstract: The spatiotemporal characteristics of rainy season precipitation for the five climatic subareas of Northwest China arid region (NCAR) under the background of global warming were investigated by using the daily precipitation data at 77 representative stations from 1961 to 2007, and future trends of the precipitation in the next decades were projected as well. The results are summarized as follows. 1) The precipitation in the NCAR presented significant interannual and interdecadal variabilities. The rainfall in western NCAR exhibited obvious increasing trends, especially in northern Xinjiang and the Yili River valley. There were generally two interannual periodic oscillations of five- to six-year and two- to three-year and one interdecadal cycle of eight- to eleven-year in rainy season precipitation time series in most areas of the NCAR, but in the Hexi Corridor, the thirteen- to fourteen-year long cycle dominated the interdecadal variability. 2) The abrupt change dates of precipitation in the five subareas were distinctively different from each other. The abrupt change from less to more than normal occurred in southern Xinjiang in the early 1980s, and then reached northern Xinjiang in the middle 1980s, the opposite trend abrupt change occurred in the Yili River valley and the Hexi Corridor region in the early 1990s, however no remarkable trend change was detected in the Alxa Plateau. 3) In the next interdecadal cycle, the precipitation will sustain the less than normal regime until the year of 2015 in western NCAR, afterwards return to the more than normal regime; while the precipitation may become more than normal in the next eight to eleven years in the Alxa Plateau.