四川不同等级雾的时空分布及其生消时间

Analysis on Spatial and Temporal Distribution of Fog with Different Intensities in Sichuan

利用四川省153个气象观测站点的逐时能见度和相对湿度资料,根据水平能见度将雾分为大雾、浓雾、强浓雾和特强浓雾四个等级,分析了四川不同等级雾的时空分布、持续时间及生消时间,结果表明:四川地区,雾在冬季最多,夏季最少,特强浓雾在4~9月比较罕见;各等级雾均在后半夜到早上(03~09时)最为频发,午后到晚上最少,强浓雾和特强浓雾几乎不会在午后到晚上(13~20时)发生;四川盆地是雾的多发区,川西高原和攀西地区雾较少,四川大部地区没有强浓雾和特强浓雾发生;四川大雾和浓雾持续时间短,一般为1~3h;强浓雾和特强浓雾一旦形成,便不容易在短时间内消散;成雾时间主要在夜间到日出前,消雾时间主要在日出后。

Using the hourly visibility and relative humidity data of 153 meteorological observation stations in Sichuan Province,the fog is divided into four levels according to the visibility:heavy fog,dense fog,strong dense fog and extra strong dense fog.The temporal and spatial distribution,duration time,generation and disappearance time of different levels of fog in Sichuan are analyzed.Studies have shown that the frequency of fog is most in winter and least in summer,and extra strong dense fog is rare from April to September.The most frequent time period for the four levels of fog is from 3:00a.m.to 9:00 a.m.,and the least is from noon to night.Strong dense fog and extra strong dense fog rarely occur from1:00 p.m.to 8:00 p.m.Sichuan Basin is a fog-prone area.There is less fog in the western Sichuan Plateau and Panxi area,and there is no strong dense fog and extremely strong dense fog in most areas of Sichuan.The heavy fog and dense fog in Sichuan lasts for a short time,generally 1~3 hours.Once strong dense fog and extremely strong dense fog are formed,it is not easy to dissipate in a short time.The generation time of fog is mainly from night to sunrise,and the disapperance time is mainly after sunrise.