陕西近50年极端气温事件分析

为分析陕西极端温度事件的气候变化特征,选用陕西75站1961～2010年逐日平均气温、最高气温和最低气温资料,应用气候统计诊断分析方法,分析了陕西近50年极端气温事件的气候变化事实。结果表明:近50年陕西极端冷事件发生的频次呈显著减少趋势,其中陕北长城沿线风沙区和黄土高原沟壑区的冷夜日数、冷昼日数、结冰日数、冬季寒冷日数、冬季严寒日数减少趋势尤为显著;关中平原霜冻日数、冷夜日数、冷昼日数呈明显减少趋势,秦岭南麓浅山区和汉江河谷及巴山山区冷夜、冷昼日数也呈现减少趋势。与此同时陕西极端暖事件发生频次呈显著增多趋势,陕北长城沿线风沙区暖夜、暖昼日数线性增加率为6～7d/10a,秦岭南麓浅山区暖昼日数增加趋势显著,其线性增加率达到6.3d/10a,而关中平原炎热夜数也呈比较显著的增加趋势。

Analysis on Extreme Temperature Events in Shaanxi Province During the Past 50 Years

75 stations were selected to analyze the climatic change characteristic of extreme temperature events in Shaanxi.Based on the daily average temperature,the maximum and minimum temperature data during 1961～2010,using the climatic statistical diagnosis method,the climatic change characteristic of extreme temperature events were analyzed during the recent 50 years in Shaanxi.The results showed that,in recent 50 years,the frequency of the extreme cold temperature events had revealed a significant decreasing trend in Shaanxi,especially on the numbers of cold nights,cold days,ice days,very cold days and extreme cold days in winter in desert area along the Great Wall in North of Shaanxi and gully regions of loess plateau.The numbers of frost days,cold nights,and cold days showed a significant decreasing trend in Guanzhong Plain,the numbers of cold nights,cold days also showed a decreasing trend in the south Qinling shallow mountains,Hanjiang river valley and Bashan mountain area.Meanwhile,the frequency of the extreme warm temperature events showed a significant increasing trend in Shaanxi,the increasing rate of the warm nights and warm days in desert area along the Great Wall in North of Shaanxi was 6～7d/10a.Frequency of the warm days showed a significant increasing trend in the south Qinling shallow mountains and the increasing rate was 6.3 d/10a.The increasing trend of tropical nights was obvious in Guanzhong Plain.