近40a西北干旱区极端气候变化趋势研究

本文选取了西北干旱区21个代表站点1961-2000年逐日气温和逐日降水量资料。用百分位阈值法分析极端年最低温度、年最高温度和极端降水量变化特征及其各分区极端气候变化趋势。研究结果表明:(1)西北干旱区近40a年最低温度的天数有减少的趋势,而年最高温度的天数略有增加趋势。(2)西北干旱区年最低温度有增加趋势,年最高温度略有减少趋势。从分区看,北疆和南疆的年最低温度有升高趋势,年最高温度有下降趋势;河西走廊、柴达木盆地年最低温度和最高温度有升高趋势。(3)近40a西北干旱区极端降水的天数增加了2天。

Study On Trends Of Extreme Climate Change in the Arid Region of Northwest China in Resent 40 Years

Based on the precipitation data of 21 representative stations during the period from 1961 to 2000,used percentile threshold method to analyze the trends of minimum temperature,maximum temperature,extreme precipitation and extreme climate changes in each subarea.The results showed that:(1) There was a remarkable decreasing trend of days of minimum temperature during the period,but days of maximum temperature has increasing trend in the arid region of Northwest China in resent 40 years.(2) There was increasing trend of annual minimum temperature,and annual maximum temperature showed decreasing trend.Annual minimum temperature showed increasing trend,annual maximum temperature showed decreasing trend in the northern and southern Xinjiang;Annual minimum temperature and annual maximum temperature showed increasing trend in Hexi passageway and Chaidam Basin.(3) Days of extreme precipitation increased 2 days in resent 40 years.