西北干旱区近50年气候变化特征与趋势

Trend and Characteristics of Climatic Change in Arid Region of Northwest China in Resent 50 Years

20世纪后期全球增暖趋势越来越明显,受全球增暖的影响,西北地区的气候也将受到不同程度的影响。选取了西北干旱区1951～2000年的21个代表站点气温、降水量资料,采用趋势系数法对西北干旱区近50年气温和降水变化进行分析,找出各分区的变化趋势。结果表明:近50年西北干旱区气温呈上升趋势(0.22℃/10 a),1986年后气温明显升高;柴达木盆地和新疆北部升温较大;各季都有增温趋势,贡献最大的是秋冬两季。降水变化有增加的趋势(3.2 mm/10 a),年降水量贡献最大的是夏季;各区降水都有增加,其中新疆北部降水增加最多。西北干旱区近50年气温升高趋势是南北高,中间低;降水量增加趋势从东南向西北呈现递增的格局。

The global warming becomes evident from the last years of the twentieth century, the climate of North- west China is affected by it. Based on the month data of the temperature and precipitation from 1951 to 2000, this paper analyzes the climatic change in the arid region of Northwest China using trend coefficient method to find out the trends of change subareas. The results indicate that the temperature appears to be ascending（0.22℃/10 a） in recent 50 years, especially in the Chaidam basin and north Xinjiang, the jump point happened in 1986. Seasonal temperatures tend to be increasing trend, mainly in autumn and winter. Precipitation appears to be ascending （3.2 mm/10 a）, obviously increasing in summer precipitation. Precipitation shows increasing trend each subarea, especially in the north Xinjiang. Trend of climate change is that amplitude of temperature warming in southern and northern arid area of Northwest China is bigger than that in the middle parts, trend of precipitation increasing is from southeast to northwest.