关键词: 气候变化, 年平均气温, 降水量, 阿勒泰, 新疆

Abstract: Climate change is very remarkable in Xinjiang. Climate warming is one of the main causes resulting in degeneration of ecological environment and frequent occurrence of natural disasters. It belongs to the typical cold continental climate in Altay Prefecture, where drought and strong wind occur frequently in spring, summer is short but not hot, winter is long and cold, and the seasonal snow cover is thick. Related data show that the extreme weather events, such as snowstorm, rainstorm, low temperature and drought, occur frequently in Altay Prefecture in recent 10 years. To understand the environmental effect over Altay Prefecture of Xinjiang, in this paper climate change in recent 50 years is studied using the temperature and precipitation data observed by 6 typical meteorological stations in the prefecture during the period 1961-2008. The results show that the mean annual temperature in Altay Prefecture was in an increase trend in recent 50 years, especially since 1985. The mean annual temperature in recent 10 years was 1.76 ℃ higher than the average in the 1960s. The increasing rate of mean annual temperature was 0.49 ℃/10 a, which was higher than that in entire Xinjiang and even in north Xinjiang. The increasing rates of mean minimum and maximum temperatures were 0.71 ℃/10 a and 0.36 ℃/10 a respectively, and the increase of mean minimum temperature was much higher than that of mean maximum and annual temperature. The maximum and minimum temperatures in recent 10 years were increased by 1.33 ℃ and 2.56 ℃ respectively compared with that in the 1960s. High temperature occurred mostly after the 1990s, and low temperature occurred mostly during the period from the 1960s to the 1970s. An abrupt change of mean annual, minimum and maximum temperatures occurred after 2005. Annual precipitation was also in an increase trend since recent 48 years, its increasing rate was 10.0 mm/10 a, but it was lower than that in north Xinjiang (19.75 mm/10 a). There is a positive correlation between temperature increase and precipitation increase, that is, climate in Altay Prefecture is changing from warming-drying type to warming-wetting type, and such trend is basically accordant with that in entire Xinjiang and northwest China. The increasing rates of precipitation in winter, spring, summer and autumn during the period from 2000 to 2008 were 17 mm/10 a, 10 mm/10 a, 11 mm/10 a and 3.8 mm/10 a respectively. The annual, winter, spring, summer and autumn precipitations in recent 10 years were increased by 35.74 mm, 68.40 mm, 2.74 mm, 61.63 mm and 27.18 mm respectively compared with those in the 1960s. Five serious snowstorms occurred during the period from 2000 to 2004. Climate change in Altay Prefecture is jointly affected by natural factors and human activities.

Key words: climate change, mean annual temperature, precipitation, Altay Prefecture, Xinjiang