昆山50a最高气温变化特征

利用1961—2010年昆山逐日最高气温资料,采用趋势分析、滑动平均、小波变换等方法,分析了昆山市50a平均最高气温的变化特征,以及高温天气的气候特征。结果表明:昆山年平均最高气温整体呈振荡上升趋势,1980s后期开始上升趋势显著。50a的年平均最高气温存在着24 a、15 a、10 a左右的年代际变化周期以及4 a的年际变化周期。高温总日数从1990s起明显增多,21世纪以来高温总日数进一步增加。高温初日呈现逐渐偏早的趋势,终日呈现"晚—早—晚"的趋势,高温时间逐渐延长。高温过程发生在6月下旬至9月上旬,各级高温过程数都以7月最多,8月次之,21世纪前10年高温过程数最多。

Change characteristics of maximum temperature in past 50 a in Kunshan

The variation characteristics of average maximum temperature and high temperature days were analyzed by the linear trend method, sliding average method and the wavelet translation method, based on the daily maximum temperature in Kunshan from 1961 to 2010. The results showed that average maximum temperature increased with slight fluctuation. The average maximum temperature had an obvious increasing trend since late 1980s. Its oscillation period was 24 a, 15 a, 10 a and 4 a. The change in the number of high temperature days showed an obvious increasing trend since 1990s, especially since 2001. The first days of maximum temperature had an earlier trend and the last days of maximum temperature had a later-earlier-later pattern. The high temperature duration was increased gradually. High temperature processes occurred from the last ten days of June to the first ten days of September. The maxi mum number of each type of high temperature process belonged to July, while August took second place. In the first ten years of the 21st century, there was the maximum number of each type of high temperature process appeared most frequently.