1961~2005年中国大雾天气气候特征

利用1961～2005年中国541个地面台站观测的能见度和相对湿度资料,分析了中国大雾时空分布特征和趋势变化特征.结果表明:中国大部分地区冬半年大雾日数明显偏多.夏半年明显偏少.其中11月最多,6月最少.在空间分布上,中国东部降水量较多的平原和丘陵年均大雾日数较多,而内蒙古大部和中国西部大部分地区年均大雾日数较少,多在1天以下.长江中下游和黄淮地区一些省市,是大雾天气多发的地区,并且具有明显正变化趋势,年大雾天气日数呈波动增多的趋势,波动的周期大约为1.5年.1982、1987、1989～2000年和2002年是大雾日数较多的年份,而1967年则是大雾日数明显偏少的年份.

Climatic Characteristics of Heavy Fog Weather in China from 1961 to 2005

The temporal and spatial distribution characteristics and variation of heavy fog days in China are analyzed by using the data of visibility and relative humidity of 541 ground stations over China from 1961 to 2005. The results show that there is obviously more heavy fog days in the winter half year than in the summer half year, the most in November and the least June. The spatial distribution shows that the annual mean fog days are much more in the eastern China, and obviously less in the most parts of Inner Mongolia and the western China, with the annual mean number of fog days less than 1 day mostly. Heavy fogs occur frequently, and there was obvious increasing and fluctuating trends in annual fog days with a period of about 1.5 years in the middle and lower reaches of the Yangtze River and some parts of the Huanghuai region. The years of 1982, 1987, 1989 to 2000, and 2002 were more than normal years, and 1967 was a less than normal year.