近35年南充大雾特征分析

Characteristics Analysis of Heavy Fog for 35 Years in Nanchong City

利用雾霾统计14∶00法、NCEP再分析资料,对近35年南充大雾天气的时空分布特征及其成因进行了初步分析。结果表明,大雾主要集中在20世纪90年代;就季节而言,大雾天气主要出现在秋冬季;从空间分布来看,雾日主要出现在高坪,浓雾和强浓雾主要出现在仪陇,高坪和仪陇两站的雾日数占全市总雾日数的70%以上。低层湿度较大、风力较小、层结比较稳定的天气形势有利于大雾天气的形成,再加之晴朗少云的夜间辐射冷却(秋冬季)及特殊的地形作用(高坪站沿江的城区地形及仪陇站较高的海拔高度),共同构成了南充大雾天气成因;大雾天气与空气污染有较好的相关性,当连续出现大雾天气时,对应AQI指数和空气污染等级升高。

Based on the method of haze statistics 14∶ 00,and NCEP reanalysis data,the temporal and spatial distribution characteristics of heavy fog in Nanchong during the last 35 years and their causes were analyzed. Results showed that fog days in Nanchong were mainly concentrated in the 90＇s. In terms of seasons,fog days mainly occurred in autumn and winter. From the point of spatial distribution,fog days mainly appear in Gaoping,dense fog and strong fog mainly appear in Yilong. Fog days of Gaoping and Yilong stations accounted for over 70% of the total number in Nanchong City. Low humidity is bigger,and smaller wind,the weather situation of relatively stable stratification is in favor of formation of heavy fog weather,coupled with the sunny,cloudless radioactive cooling at night（ autumn and winter） and special effect of topography（ the urban terrain of Gaoping station along river and higher altitude of Yilong station）,these together constitute the cause of heavy fog weather in Nanchong. It has good correlation with air pollution. When the fog weather occurs continuously,the corresponding AQI index and air pollution levels are increased.