合肥市近50年最高气温变化特征

Characteristics of Maximum Temperature Change in Past 50 Years in Hefei

利用合肥市1953-2005年逐日最高气温资料，采用滑动t检验等统计方法，分析了合肥市平均最高气温、高温日数和高温出现初终日的变化特征。结果表明：合肥市近50年来平均最高气温呈“上升-下降-上升”的趋势，并且平均最高气温在1968和1988年附近发生了突变。合肥市高温日数也呈“增多-减少-增多”的趋势，但年累计高温日数没有很明显的突变；高温日5～9月都有出现，其中7月出现的次数最多，占总日数的49．7％，8月次之，占40．5％。合肥市高温持续的时间经历了由长变短再变长的过程，20世纪80年初期最短。

The variation characteristics of average maximum temperature, the number of high temperature days, and the dates of the first and last days of high temperature occurrence are analyzed with the observational data from 1953 to 2005 in Hefei, based on the moving t test technique, etc. The results indicate that the changes of the average maximum temperature shows an increasing-decreasing-increasing trend, with the abrupt changes taking place in 1968 and 1988. The change of the number of high temperature days shows an increasing-decreasing-increasing trend, without evident abrupt change. High temperature days occurred mainly from May to September, most frequently in July （49.7 %） and secondly in August （40.5 %）. The high temperature duration in Hefei underwent a long-short-long change, with the shortest in the early 1980s.