三江源地区1961~2005年气温极端事件变化

利用三江源地区11个气象台站1961~2005年逐日最高气温和最低气温资料，分析了三江源地区极端高温和极端低温的变化趋势。研究表明：近45年来，白天和夜间温度极端偏高的日数明显增多，分别以26 d/10 a和44 d/10 a速度在增加;白天和夜间温度极端偏低的日数显著减缓，分别以41 d/10 a和85 d/10 a的速度显著减少;年极端低温和极端高温分别以042℃/10 a和029℃/10 a的速度增加;白天和夜间温度极端偏高的日数增加主要发生在冬季和夏季，而白天和夜间温度极端偏低的日数减少主要发生在春季和秋季，夜间温度极端偏低的日数减少趋势最为明显;长江源地区极端气温变化对区域增温的响应更为敏感。

CHANGE IN EXTREME TEMPERATURE OVERSANJIANGYUAN REGION IN THE PERIOD FROM 1961 TO 2005

Based on daily minimum and maximum temperature data in 11 meteorological stations obtained in the period from 1961 to 2005 over Sanjiangyuan region,the spatial and temporal characteristics of climate extremes were studied.The main results are summarized as follows:The trends for the annual number of warm days ( 26 d/10 a) and warm nights (44 d/10 a) are on the rise,while decreasing trends are found in the number of cold days (41 d/10 a) and cold nights (85 d/10 a);The changing trends of annual minimum temperature (042℃/10 a) is higher than that of maximum temperature(029℃/10 a);The increasing number of warm days and warm nights mainly occurs in winter and summer,while the decreasing number of cold days and cold nights occurs in spring and fall,and the trend of cold nights decreases significantly;The change in extreme in the source regions of the Yangtze River is more sensitive to the climate warming compared with the other two source regions.