成都地区近30年大雾的气候特征分析

本文利用成都市1981~2010年大雾观测资料对成都地区大雾的气候特征和气候背景进行分析。结果表明,成都地区大雾日数总体减少,减少幅度为3.2d/a,但各季减少幅度及变化显著不同;大雾存在明显的日变化,主要集中在05~08时生成,08~12时消散;空间分布上,呈现南部偏多,西北部和东部偏少的趋势,西北部和西南部减少幅度小于南部。当气压950.0~970.0hPa、气温为5~15℃、相对湿度70%~90%、风速0~3m·s-1、近地面有逆温时,出现大雾的频率最高。 

Climatic Characteristics of Fog in Chengdu in Recent 30 Years

The climatic characteristics and background were analysed by using the observational data of fog in Chengdu in the period of 1981 ~ 2010. The results showed the fog days had a decreasing trend by 3.2 days per year. The change was obviously different in each season. The fog days had a significant change which the formation was mainly concentrated in 5 to 8 o'clock and the dissipation was in 8 to 12 o'clock. The spatial distribution showed the fog was too much in south,and was little in northwest and east of Chengdu. The decreasing amplitude in the northwest and eastern is less than the south. The fog occurred with the highest frequency when the pressure was 950. 0 to 970. 0 h Pa,the temperature was 5 to 15 degree,the relative humidity was 70 to 90,the wind speed was 0 to 3 meter per second and the inversion was in surface.