气候变化对重庆高温和旱涝灾害的影响

Impact of Climate Changes on High-Temperature,Drought and Flood Disasters of Chongqing

利用重庆地区1961—2006年逐日气象观测资料,研究了气候变化对重庆高温和旱涝灾害的影响。结果表明:重庆区域显著的增暖开始于20世纪90年代后期,突变检验结果显示气温距平的突变出现在1997年。增暖后,极端高温事件发生频次增加趋势明显,高温热浪风险显著上升,极端降水事件发生频次也呈现出显著增加趋势,洪涝灾害的风险不断上升。进一步分析了区域平均各级别降水日数的变化趋势,结果显示小雨和中雨日数减少趋势明显,使得干旱的风险增大。将区域平均气温距平序列分为全球气候变化对重庆区域平均气温的影响和重庆区域平均气温的自身变率两部分,发现在增暖后,全球气候变化对区域气温变化的贡献较增暖前增大。分别计算2006年全球气候变化和区域自身变率对重庆异常气温的贡献,发现2006年重庆异常高温可能是受全球气候变化和区域自身的变率共同作用的结果,但以区域自身的变率为主。

Daily meteorological data from 1961 to 2006 of Chongqing area have been employed to diagnose the impact of climate changes on high-temperature,drought and flood disasters of Chongqing.Results show that significant warming of Chongqing area began at late 1990s.The abrupt temperature change occurred in 1997.During warming period,extreme high temperature event increased obviously,the risk of heat wave rose significantly,meanwhile extreme precipitation event also increased obviously,the risk of flood rose significantly.Furthermore,the trends of each grade regional average precipitation days have been analyzed,the precipitation days of light and moderate rain decrease obviously,which may lead to the risk of drought to increase significantly.Put regional temperature anomalies into two parts,one is the impact of global climate changes on it,the other is regional self-variability.It was found that the contribution of global climate changes to regional temperature variations increased significantly during warming period. Then we calculated the contributions of global climate changes and regional self-variability in 2006,respectively, results suggest that global climate changes and regional self-variability may cause the abnormal high temperature of 2006,but regional self-variability is the main contributor.