天水地区冬半年最低气温的概率分布特征

Probability Distribution of Minimum Temperature during Half Year of Winter in Tianshui

根据1971-2007年天水7个站冬半年(11月-翌年4月)平均最低气温资料,使用统计检验的方法,分析了近40a天水冬半年最低气温的突变事实,在此基础上给出了气候变暖前后最低气温的概率分布,比较了变暖前后天水最低气温空间分布的差异。结果表明:1)20世纪90年代中期天水冬半年最低气温发生了显著突变,进入异常增暖时期,其增温程度比平均气温明显;2)增暖后天水最低气温的概率分布发生了明显的变化,最低气温偏冷的概率显著减小,偏暖的概率明显增大;3)气候变暖后除关山地区最低气温上升幅度不显著外,河谷、渭北地区最低气温均呈显著增加趋势。

Based on the mean minimum temperature data of seven meteorological stations in 1971 -2007 in Tianshui during the half year of winter, which was from November to April of the next year, the abrupt changes of the minimum temperature were analyzed by using Mann-Kendall statistic test. The probability distributions of the minimum temperature series for the colder periods in 1971 - 1972 and 1995 - 1996 and warmer periods in 1996 - 1997 and 2006 -2007 were analyzed. The differences of the spatial distribution of the minimum temperature between the two climatic periods were also compared. The results showed the significant increase of the minimum temperature occurred in the middle of 1990＇s. Its increasing amplitude was larger than that of the mean temperature. The partial cold probability of the minimum temperature apparently reduced, while the partial warm probability of the minimum temperature increased. The minimum temperature in the North of the Wei River and the valley of Wei River significantly increased with exception in the Guan Mountain Areas.