中文摘要：

雾的记录有明确的天气指示意义。通过分析1951—2005年中国大陆743个地面气象站的资料,对中国大陆雾、轻雾的长期变化趋势有如下认识：我国大陆雾日地理分布基本气候特征呈现东南部多西北部少的特点,冬半年雾日数多夏半年少。各年代的差异在不同地区不尽一致。西南地区是我国雾日最多的地区,四川盆地一年有雾日20余天;华北平原和东北平原在冬春季节会出现严重的持续性雾天气。长江以南各省的轻雾日数明显多于长江以北地区,而且1980年代以后轻雾日有明显增加;西南地区是我国轻雾日最多的地区,四川盆地一年有轻雾日100余天。

英文摘要：

Fog is an important indicator of weather.Long-term trends of fog and mist variation were known by studying meteorological data from 743 surface weather stations in mainland China for the time between 1951 and 2005.For the general geographic distribution of foggy days in mainland China,it is climatologically more in the southeast than in the northwest China and fog appears more in the winter half of the year than in the summer half.Differences are insignificant between decades.Southwest China is the part of the country with the most fog appearance and fog appears on more than 20 days in the year in Sichuan Basin.Serious,persistent heavy fog usually appears in winter and spring over plains in North China and Northeast China.Days with mist are much more frequent in provinces south of the Yangtze River than in those north of it and there is a general increase of misty days after the 1980s.Southwest China is the part of the country where there are most days of mist and Sichuan Basin is misty for more than 100 days in the year.