The Regional Difference and Catastrophe of Climatic Change in Qilian Mt. Region

Based on climatic data of 8 stations in the Qilian Mt. region, methods of regression analysis and moving average were used to study the climatic changing trend of the study area under the background of global warming. Results showed that the temperature increased after the mid-1980s and climatic warming has accelerated since the 1990s due to the rise of temperature in autumn and winter. The precipitation experienced a changing trend, that is lower (the 1960s)--higher (the 1980s)--lower (the 1990s)--higher (after 2000). The regional difference in temperature rise is, with the main Heihe River as the divide, characterized by the fact that it is increasing from south to north in the middle-eastern Qilian Mt. region while decreasing from south to north in the middle-western. Also the precipitation presents obvious spatial change. The rising range is decreasing from east to west in the eastern Qilian Mt. region, while decreasing from south to north in the western. What's more, methods of T checking, Cramer and Mann-Kendall were employed to analyze climatic break, indicating that the abrupt change of temperature was more noticeable than that of precipitation in the study area. The abrupt change of spring and summer temperature happened in 1997 while that of autumn and winter appeared in 1985. Moreover, the temperature abrupt change in 1987 was more obvious than in 1997 because the scale of temperature rise was higher in autumn and winter than in spring and summer, and the precipitation break in the eastern, middle and western regions happened in 1980, 1972 and 1969, respectively.