STUDY OF LOW VISIBILITY IN MOUNTAINOUS AREASBY AUTOMATIC WEATHER STATIONS' DATA OF GUIZHOU
From 6 new automatic weather stations' data in the summer half-year,we selected 13 low visibility events.The results are shown as follows.All the events happened in late spring and early autumn,with weather backgrounds of rainfall and temperature decline.All events took place in limited areas and mainly at two relatively high-altitude stations,because of interactions between terrain fog,frontal fog,low cloud,and topographic influence.The events are classified into long events and short events.Long events showed a trunk-shaped pattern,in which the visibility slowly declined at the initial time.During the events,visibility fluctuated quickly and obviously,and repeated for several hours,posing much larger danger.More events,forming over mountainous areas,were short and the visibility dropped quickly.They were small-sized,strong,and sudden,which had limited influence but was hard to predict.Studies of meteorological elements showed that humidity reached 100％ prior to the event and temperature was steady,and most long events had little rainfall and wind speed was negatively correlated with visibility,especially in short events.The "mountainous area agglomerated fog" connected with low cloud directly and happened with considerable wind speed.Two events that happened over two nearby stations in consecutive points of time were either frontal fog or low-cloud,reflecting the complexity of this type of fog in mountainous areas.Low visibility events in mountainous areas can be better identified by combined use of automatic weather stations and background data of weather condition.
low visibilitymonitoringautomatic weather stationmountain areaagglomerated fog
国家科技期刊平台
NSTL
万方数据
维普
