商丘市极端天气气候事件变化趋势

利用1961~2004年逐日气象资料,分析了商丘市近44年来极端天气气候事件的变化趋势。结果表明:近44年来,商丘市暴雨、大暴雨和达到极端干旱标准的总天数都存在增加的趋势,但是这种趋势在统计上并不显著。极端高温事件年发生频率增加而极端低温事件发生频率减少;季节变化以冬、夏两季最为明显,其中冬季极端高温事件增加而极端低温事件减少,变化趋势都通过了99%的显著性水平检验;夏季与冬季变化趋势相反,其中极端高温事件显著减少,通过95%的显著性水平检验。寒冷期长度和炎热期长度都显著减少,分别通过99%和95%的显著性水平检验。

Extreme Climate Events in Shangqiu over Last 44 Years

Extreme climate events in Shangqiu are analyzed on the basis of daily mean temperature and precipitation observations of eight stations from 1961 to 2004.Heavy rain events,defined as those with daily precipitation being or larger than 50 mm,show no significant secular trend.In winter,the occurrence frequency of hot days increased,while that of low temperature events decreased significantly with the confidence level being 99%.In summer,vice versa with the confidence level being 95%.The variation periods of both hot days and cold days were shortened significantly(at 99% and 95% confidence level,respectively).