中文摘要：

使用上海1873--2006年共134年冬季气温资料和1961--2004年NCEP／NCAR再分析资料。分析了上海冬季气温的变化特征及其可能成因。结果表明，百余年来上海冬季气温有3次明显的增温过程和2次降温过程，总体上呈现出显著的增温趋势，其中1970年代以来增温幅度最大。上海冬季气温具有2年、40年和80年的变化周期，在1980年代中期冬季气温发生增暖突变。134年间上海冬季平均日数显著缩短，趋势倾向率为-1．6d／（10a）。上海冬季气温变化是全球气候变化和局地城市化双重作用的结果。上海冬季气温变化与北半球温度和全中国气温的变化基本一致，西伯利亚高压和东亚冬季风强度的减弱使得上海冬季气温增暖，局地人口增加、土地利用变化等因素也对上海冬季气温起到了一定的增温作用。

英文摘要：

The characteristics of winter temperature variation in Shanghai from 1873 to 2006 and their probable causes are analyzed with the observation data from Xujiahui station and the NCEP/NCAR reanalysis data from 1961 to 2004. The results indicate that in the past 134 years, winter temperature in Shanghai increased significantly, oscillating with cycles of about 2, 40 and 80 years. From 1873 to 2006, winter temperature varied in three obvious warming periods and two cooling periods and had the most increase after 1970s. In the middle of 1980s, it showed an abrupt warming change. The average number of wintry days decreased significantly with a linear trend of 0.16d/10a in the past 134 years. The variation was influenced jointly by the global climate change and regional urbanization. Its characteristics are consistent with those for the Northern Hemisphere and the whole of China. The winter warming may also result from the weakening of East Asian winter monsoon and Siberian High. Moreover, local human activities, such as population explosion and land use change, may to some extent be responsible for the long-term change of Shanghai＇s winter temperature.