巢湖地区能见度特征及其影响因子分析

Analysis of visibility characteristics and its influencing factors over Chaohu Lake area

基于巢湖地区高密度的能见度监测数据,分析了其能见度时空分布特点,初步探讨了湖泊及周边地形对能见度及大雾形成的影响机理。结果表明:受湖泊气温、风、水汽等要素的影响,巢湖沿岸能见度低于远岸地区;一般远岸地区雾较近岸先形成,但是近岸地区雾持续时间长,且消散慢;在湖陆风或主导风作用下,巢湖北岸和西南岸雾的发生次数和持续时间明显多于其他地区;巢湖东南岸由于受山脉的影响,夜间干冷山风提高了岸边能见度,减少了大雾的发生。

Based on the high-density visibility monitoring data from Chaohu Lake area,the spatial and temporal distribution characteristics of visibility were analyzed,and the influence mechanism of the lake and surrounding topography on visibility and fog formation was preliminarily discussed.The results show that the visibility over Chaohu Lake is lower than that of far shore due to the influence of temperature,wind and water vapor.Generally,fog forms first in the far shore area compared with the nearshore area,but the nearshore area fog lasts for a long time and dissipates slowly.Under the action of lacustrine wind or dominant wind,the occurrence and duration of fog on the north and southwest coast of Chaohu Lake are obviously more than those in other areas.Due to the impact of mountains on the southeast coast of Chaohu Lake,dry and cold mountain winds at night improve the visibility on the shore and reduce the occurrence of fog.