摘要
利用位于九华山不同海拔高度上测站和自动气象站的气象资料,对比分析雾的时空分布特征,探讨地形的影响作用.结果表明:年平均雾日平地区为19d,低山区为82d,半山区为145d,高山区为110d,平地区雾日呈逐年增加的趋势,山区雾日呈逐年减少的趋势;平地区的雾主要出现在秋季和冬季,山区的雾多发生在春季和冬季;平地区雾日10月—次年1月出现频率较高一些,山区雾日的高值出现在3月,低值出现在7月,1—4月山区雾的发生频率明显高于平地区;平地区和低山区最易生成雾的时间在05—07时,半山区和高山区在04—08时;平地区和低山区的雾主要在08—10时消散,半山区和高山区主要在09—11时;半山区雾的平均持续时间和最长持续时间均大于其他区域,高山区雾的最短持续时间仅有0.2h;未饱和湿空气随气流进入喇叭口后,受到上升运动的作用,气团抬升冷却,在喇叭口底部区域水汽达到饱和而形成雾;地形逆温的存在提供了稳定的层结条件,对雾的形成和维持起着重要作用;山区风场的辐合作用有利于雾的形成和维持.
Meteorological data from automatic obselvation stations at different altitudes of Mount Jiuhua are used to analyze and compare the temporal and spatial distribution characteristics of fog, and the topographic effect as well. The results show that the average annual fog days are 19,82,145,110 days for flat land,low level, middle level and high level mountain areas, respectively, with increasing trends in flat land and decreasing trends in mountain areas. The temporal distribution of fog shows different characteristics in flat land and mountain areas. In flat land, fog oc- curred mainly in autumn and winter with peak value in October to January of next year, while in mountain areas, fog occurred mainly in spring and winter with peak value in March and low value in July. Fog mostly formed during 05:00---4)7:00 and disappeared during 08:00--10:00 in flat land and low level mountain area,while formed during 04:00--08:00 and disappeared during 09 :O0--11:00 in middle and high level mountain areas. The average and maximum fog lasting time is longer in middle level mountain area than it in other areas, and the shortest fog lasting time appeared to be 0.2 hour in high level mountain area. In the Mount Jiuhua, unsaturated air flows into the fun- nel-shaped area and cools down in ascending process, then the water vapor will reach saturation and the fog is formed thereby. Topographic temperature inversion provides stable stratification conditions, thus is significant for fog formation and duration. Convergence of wind field in mountain area also favors the fog formation and duration.
出处
《南京信息工程大学学报(自然科学版)》
CAS
2013年第3期229-235,共7页
Journal of Nanjing University of Information Science & Technology(Natural Science Edition)
基金
安徽省池州市科技社会发展项目(CZ201040)
关键词
雾
时空分布
地形作用
九华山
fog
temporal and spatial distribution
effect of topography
mount Jiuhua