我国三峡库区高温天气的变化分析

根据三峡库区及其周围30个气象站1961～2010年的逐日气温资料，采用常规统计方法分析了50 a来三峡库区高温的时空变化特征。结果表明: 过去50 a，三峡库区年均高温日数为2407 d，存在23和31 a尺度的周期振荡，于1979 年发生了由多到少的突变；高温日平均最高气温为3669 ℃，具有3 a尺度的变化周期。8月的高温日数最多且高温日平均最高气温最高。20 世纪80年代高温日数与高温日平均最高气温为负距平，在21 世纪最初10 a，高温日数显著增加，高温日平均高温气温增高。三峡库区高温日数呈峡谷多，山区和丘陵少，库区北部多、南部少的分布特点。三峡库区蓄水后高温趋势变化不显著

CHANGE ANALYSIS OF HIGH TEMPERATURE IN THE THREE GORGES AREA

Based on daily temperature data of 30 stations in or around the Three Gorges Area during 1961-2010,the dynamic temporal and spatial variation characteristics of high temperature were analyzed by mathematical statistical methods.The results showed that the mean annual high temperature days were 2407 days,oscillating with a cycle of about 23 or 31 years,the abrupt change from many to few in 1979,and the mean daily highest temperature during annual high temperature days was 3669℃, oscillating with a cycle of about 3 years in the past 50 years.The frequency and intensity of high temperature in August was the most in the year.Both the high temperature days and mean daily highest temperature during annual high temperature days were negative anomaly in 1980s，and in the first 10 years of the 21st century，the high temperature days and mean daily highest temperature during annual high temperature day increased.The high temperature days in the Three Gorges Area were more (less) in gorges (mountains and hills) and north (south) of the Three Gorges Area.The change trend of high temperature was not significant in the Three Gorges Area after water storage.Besides,it should be noted that with storing water of the Three Gorges,the increasing water level and surface of it might have some influence on the local climate.Now,although some exploratory researches have been done,they could not reveal the influence of the Three Gorges on local climate completely due to the observation data. This need long term observation and study