Climate Change of the Cold Wave Frequency of China in the Last 53 Years and the Possible Reasons
Climate Change of the Cold Wave Frequency of China in the Last 53 Years and the Possible Reasons
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发表时间：
2006
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通讯作者：
Wang Zun;D. Yi
中科院分区：
文献类型：
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作者：
Wang Zun;D. Yi
本文利用1951—2004年我国740个站逐日地表温度资料,对我国寒潮频率的气候特征和气候变化进行了分析,并进一步探讨了寒潮气候变化的可能原因。 揭示了我国寒潮频率的时空分布。我国寒潮主要发生在秋季，特别是11月份。但华南和北方寒潮的时间分布并不完全相同。南方地区春季寒潮相对秋季多，北方则相反。寒潮主要发生在北方，特别是北疆和内陆中部。 蒙古国，平均每年超过10次。1951年至2003年，我国共发生区域性和全国性寒潮371次，其中全国性寒潮104次。进一步分析，主要结论如下：近53年来，我国大部分站位寒潮明显减少，特别是东北地区。全国寒潮和区域性寒潮均明显减少，且呈线性关系。 趋势系数分别为-0.031次/年和-0.063次/年。我国北方区域性寒潮减少幅度最大,线性趋势系数为-0.071次/年。寒潮从1960年代开始减少,到1970年代末急剧变化。减少趋势在冬季最显着,春季最不明显。 冬季，西伯利亚高压的强度与我国区域性和全国性寒潮的频率呈正相关，西伯利亚高压的减弱主要导致其总数的减少。在全球变暖的背景下，近53年中国地表温度和西伯利亚高压上空冷体温度均明显升高，且均呈负相关。 它们可以直接解释为什么我国寒潮频率减少，大风频率相应减少。而且，近53年来西伯利亚高压和冬季风不同程度减弱，可能导致我国特别是北方地表温度升高，通过气温变化对我国寒潮频率产生重要影响。
By virtue of the 740 stations daily surface temperature data in China from 1951 to 2004,the climatology and the climate change of the cold wave frequency of China are analyzed and the possible reasons for the climate change of it are further discussed in this paper.Firstly,a cold wave is defined according to the difference between the maximum and the minimum daily temperature and the anomaly of the minimum daily temperature from its climatological 10-day mean temperature during the period of the activity of a cold air.Then the temporal and spacial distributions of the cold wave frequency of China are revealed.Cold waves of China occur mainly in autumn,especially in November.But the temporal distributions of cold waves between southern China and northern China are not all the same.The cold waves are relatively more in spring than in autumn in southern China,with the situation being opposite in northern China.The cold waves occur mostly in northern China,especially in northern Xinjiang and middle Inner Mongolia,being over 10 times per year on average.There were 371 regional and countrywide cold waves of China from 1951 to 2003,including 104 countrywide ones.Further analyses are processed and the main conclusions are as follows: In recent 53 years,cold waves in most stations of China decreased significantly,especially in Northeast China.As for the countrywide cold wave and the regional cold wave,both of them decreased obviously and their linear trend coefficients are-0.031 times/year and-0.063 times/year,respectively.The regional cold wave in northern China decreased most,with its linear trend coefficient being-0.071 times/year.The cold wave began to decrease in the 1960s and changed abruptly in the late 1970s.The decreasing trend is most significant in winter and least significant in spring.On the basis of analyses about climatology and climate change of the cold wave frequency of China,the possible reasons why they have changed are discussed by correlation analysis.In winter,the strength of Siberian high has a positive correlation with the frequency of regional and countrywide cold waves of China.The weakening of Siberian high mainly resulted in the decrease of their total number.Under the background of global warming,the surface temperature of China and the temperature of the cold mass over Siberian high have increased evidently in the last 53 years.And they both have the negative correlation with the cold wave frequency,especially in autumn and winter and in northern China.They may explain directly why the cold wave frequency of China decreased,the gale frequency having being decreased accordingly.And,it may cause the increase of the surface temperature of China,especially in northern China,that Siberian high and the winter monsoon have weakened in the last 53 years on different degree.They have important impacts on the cold wave frequency of China through the change in temperature.