长江流域近50年来的气温变化特征

分析了1951~2000年长江流域（上、中、下游）的平均气温、平均日最低气温、平均日最高气温随时间的变化趋势特征。结果表明：长江流域近50年来年平均气温、年平均日最低气温、年平均日最高气温在20世纪50年代明显偏高，60~80年代波动下降，80年代中后期以后有所上升，90年代较80年代增温0.3℃~0.6℃之间；同时不同季节、不同区域气温呈现不同的态势，冬季平均气温、平均日最低气温在60年代以后呈上升趋势，而平均日最高气温呈下降趋势，夏季平均气温、平均日最低气温、平均日最高气温均以降温为主。

CHARACTERISTICS IN THE VARIATION OF TEMPERATURE OVER THE YANGTZE RIVER VALLEY OVER LAST 50 YEARS

This paper analysed characteristics in the variation of mean temperature,the minimum temperature as well as the maximum temperature in the Yangtze River Valley over the period between 1951 and 2000.The temperature was significantly higher in 1950s,and dropped down with fluctuation from 1960s to 1980s,and then rose up afterwards.However,the changes were to some extent different in relation to mean temperature,minimum temperature and maximum temperature in different seasons and regions.A pattern with the temperature rising up in winter but dropping down in summer on the region of upper and middle reaches,and with the mean minimum temperature rising but the mean maximum temperature dropping down was observed.A uniformly declining trend was observed in the lower reach in every season.