石羊河流域近46年来最高、最低气温时空变化特征分析

以1960～2005年石羊河流域月平均最高、最低气温资料为基础，采用气候倾向率、趋势系数、Kriging插值、Mann­Kendall突变检验、小波分析等方法对石羊河流域最高、最低气温的时空变化特征、突变特点和变化周期进行分析。结果表明： 近46年来石羊河流域最高、最低气温均有明显增温趋势，增温幅度存在季节差异，冬季增温最明显，夏季增温最弱； 增温趋势强弱的地域差异明显； 升温突变显著，突变时间存在一定季节差异，冬季最早，最低气温升温突变普遍早于最高气温，且显著性高于最低气温。最高、最低气温变化周期显著，最高气温存在4年的振荡周期，最低气温存在7～9年和4年的振荡周期。

CHARACTERISTIC ANALYSES OF TIME­SPACE CHANGE TRENDS OF THE HIGHEST AND THE LOWEST TEMPERATURE OF THE PAST 46 YEARS IN THE SHIYANG RIVER BASIN

The Shiyang River Basin lies in the northeast of Tibetan Plateau，an intersection area of three natural zones，and has a complicated climate system.
Based on monthly mean highest and lowest temperature data of 1960～2005 in this region，characteristics of time­space changes of highest and lowest temperatures over the last 46 years were analyzed by using such methods as climate tendency rate，trend coefficient，Kriging interpolation，Mann­Kendall abrupt change test and wavelet analysis. The results show that the highest temperature increased at a rate of 0.368℃/10a and the lowest temperature increased at a rate of 0.149℃/10a; the warming amplitude of the lowest temperature was remarkably higher than that of the highest temperature，which resulted in an asymmetric warming trend; and the diurnal temperature varying range was reducing. Both the highest and the lowest temperature are low in the 1960s～1980s，but into the 1990s they began to increase. The highest and the lowest temperature showed a seasonal increase，but such an increase was stronger in winter than in other seasons. The warming amplitude was obviously varying from area to area. A weak warming center of highest temperature was formed in the east of Gulang: the trend coefficient was highest over Yongchang and Wushaoling. On the other hand，for the lowest temperature，the highest trend coefficient is in the east of Gulang and the north of Minqin，whereas the lowest trend coefficient was in Yongchang and Wushaoling. Both the highest and the lowest temperature had quite obvious abrupt change and the abrupt change time was earlier in winter than in other seasons. The abrupt change of the lowest temperature occurred in 1993，whereas the abrupt change of the highest temperature occurred in 1995.The former was more remarkable than the latter. Both the highest and the lowest temperature had some change periods: 4 years for the highest temperature and 7～9 years and 4 years for the lowest temperature.
In China，the mean temperature was increasing obviously over the last 50 years and the warming mainly occurred after the middle of 1980s. The lowest temperature was increasing rapidly and the diurnal temperature varying range was reducing. In Northern China，the abrupt change of the lowest temperature occurred earlier than that of the highest temperature. Through comparison of climate change trends in China，we find that the climate change trend in the Shiyang River Basin was synchronous with the total climate change trend of China.