中国不同等级雾日的气候特征

 利用1961-2005年中国300个台站的逐日雾资料及能见度资料，分析了不同等级雾的时空分布及基本气候特征、雾生时间和持续时间的年代际变化。结果表明：雾的空间分布范围随着能见度的降低而减小；随时间的变化多呈减少趋势，但沿长江及东部沿海的重浓雾日在20世纪70年代发生突变，雾日增多；内陆、南部沿海雾生时间多在清晨06:00-08:00，东部及沿海多发生在夜间20:00-21:00；雾生频次经历少-多-少的年代际变化，90年代后频次减少，个别区域雾生时间随着年代的延伸而推后；大部分地区雾的持续时间在3 h内，12 h以上的雾区多集中在沿海、华北和陇东-山西地区，沿海、四川盆地、云贵地区90年代12 h以上雾的发生频次最高。

Climate Characteristics of Fog Days of Various Categories in China

Based on the observational data of daily fog and visibility at 300 national meteorological observatory stations of China during the period of 1961-2005, spatially and temporally distributive climate characters of fogs of various categories were analyzed through regional division. The frequencies of fog generation and duration in each decade were also calculated. Results show that the fog area was smaller when the visibility of the fog was small. Fog frequencies in most regions generally displayed a evolutional trend of less (the1960s)-more (the 1970s-1980s)-less (since the 1990s) fog days, however, super-dense fog days abruptly increased in the 1970s over the Yangtze River valley and the eastern coastal region. Fogs mostly occurred during 06:00-08:00 o'lock in inland and south coast areas, and 20:00-21:00 o'lock in eastern China and the east coast region. Fogs generally lasted for less than 3 hours in most regions; and those with a duration of more than 12 hours mainly concentrated in the coastal areas, North China, and the Longdong-Shanxi area, and its maximum frequency occurred in the coastal areas, the Sichuan Basin and Yunnan-Guizhou Plateau in the 1990s.