长沙地区寒露风气候特征及初日预测模型

Climate Characteristics and First Day Prediction Model of Cold Dew Wind in Changsha Area

根据1959—2015年长沙地区4个气象站的日平均气温资料、湖南省寒露风等级标准和构建的寒露风初日时间序列,利用数理统计分析、均生函数、最优子集回归等方法,分析了长沙地区寒露风气候特征,建立了寒露风初日预测模型。结果表明:长沙地区1959—2015年发生寒露风共97次,宁乡、望城坡、马坡岭和浏阳分别为38、28、19和12次;发生中度以上寒露风次数自西向东分别为15、10、8和5次。寒露风平均初日在9月19—22日。≤20℃的开始日期最早为9月3日(2013年),最迟为10月28日(2014年),极差为56天。9月上、中及下旬发生寒露风的概率分别为6%、32%和62%,下旬发生概率显著增加。西部宁乡约2 a一遇,东部浏阳约5 a一遇,西部宁乡频率及影响程度远高于东部浏阳的。预测模型拟合率均在89%以上,2011—2016年预测结果较好。

According the daily average temperature data at 4 observation stations in Changsha area during 1959—2015,the grade standard and time series of first day of cold drew wind in Hunan province,using mathematical statistics analysis,mean generating function,optimum subset regression and other methods,the climate characteristics of cold dew wind in Changsha area are analyzed and the first day prediction model is built. The results show that： there are 97 times cold dew wind during 1959—2015 in Changsha area,while 38,28,19 and 12 times in Ningxiang,Wangchengpo,Mapoling and Liuyang. The cold dew wind above middle level is 15,10,8,5 times from west to east. The average first day of cold dew wind is in September 19—22. The earliest beginning date of temperature ≤20 ℃ is September 3 rd（2013）,the latest is October 28 th（2014）,and the range is 56 days. In the first,middle and late ten days of September,the occurrence probability of cold dew wind is 6%,32% and 62% respectively,which is significantly increased in the late ten days. The cold dew wind in western Ningxiang occurs in about every 2 years,while in eastern Liuyang occurs in about every 5 years,the frequency and influence degree in western Ningxiang is much higher than that in eastern Liuyang. The fitting rate of prediction model is above 89%,the prediction results are better during 2011—2016.