利用观测资料， 发现中国东部冬季雾日数明显高于其余月份， 且冬季雾日数的气候统计诊断变量分布不均匀， 从而可将中国东部分为南、 北方两个区域。又根据雾日数变化趋势的强弱， 以及南北方间雾日数相关性的特点， 可将冬季分为早冬（11 -12月）和晚冬（次年1 -2月）。通过分析早晚冬时南北方雾日与海表温度的关系发现， 在早冬， 南北方两区域的雾日都受热带太平洋区域海温显著影响； 在晚冬， 北方雾日受北大西洋区域海温影响显著， 而南方仍受热带太平洋区域海温显著影响。通过分析环流发现， 早冬时， 热带太平洋区域海温的暖异常， 有利于中低纬西太副高显著增强北抬， 促使中高纬日本北部上空出现深厚的反气旋异常、 西伯利亚高压明显减弱， 从而使整个中国东部出现一致的偏南风异常， 有利于南北方雾日都增加。在晚冬， 热带太平洋对东亚中高纬地区的影响显著减弱， 异常偏南风仅能维持在南方， 仅使南方雾日偏多， 并不能影响北方的雾日变化； 而此时北大西洋区域海温暖异常通过波列的作用， 对东亚中高纬地区的影响显著， 使得北方地区受到异常东南风控制， 有利于北太平洋水汽的输送， 配合冬季气候态极强的下沉气流， 大气层结相对稳定， 使得北方地区雾日显著增多。

Based on observational data， it is evident that fog occurrence in Eastern China is notably higher during winter compared to other months.Spatial analysis of climatological statistics reveals a distinct heterogeneity， dividing Eastern China into northern and southern regions based on fog day patterns.Furthermore， winter can be subdivided into early （November and December） and late （January and February） periods， characterized by varying trends in fog occurrence and interregional correlations.Examining the relationship between sea surface temperature （SST） and fog days across both southern and northern China throughout winter， significant influences emerge.During early winter， fog days in both regions are markedly impacted by SST anomalies in the tropical Pacific.Conversely， in late winter， while the north Atlantic SST exerts a considerable influence on fog days in northern China， southern China continues to be strongly affected by tropical Pacific SST.Analyzing atmospheric circulation patterns reveals distinct mechanisms driving fog occurrences in different seasons.In early winter， warm SST anomalies in the tropical Pacific drive northward movement of the Western North Pacific Subtropical High， resulting in anticyclonic anomalies over northern Japan and weakened Siberian High， leading to increased fog days in both southern and northern areas of Eastern China.Conversely， in late winter， weakened influence from the tropical Pacific shifts the anomalous southerly winds only over southern China， while the north Atlantic SST anomalies induce anomalous southeasterly winds over northern areas， enhancing moisture transport from the north Pacific， with relatively stable atmospheric structure， thus significantly increasing fog days over northern China.