绵阳机场一次大雾过程的分析与研究

本文利用常规观测资料、机场自动观测资料、以及NCEP/NCAR的2.5°×2.5°格点的再分析资料对绵阳机场2011年12月的一次大雾过程进行分析,结果表明：高层弱高压脊控制,地面处于均压场中,是有利于绵阳机场大雾形成的一个大气环流形式;中低层充足的水汽及较强的逆温层为大雾维持提供了有力条件;大雾开始生成时,中低层有弱辐散下沉区,使中下层水汽汇合,阻止水汽向上扩散;大雾维持阶段600hPa以下为弱辐散下沉作用,大雾消散阶段600hPa以下开始弱辐合上升为主,辐散场的变化对大雾的生消演变指示意义明显;机场的小气候环境决定了当机场风向由西南或偏西方向转为东南向的过程中,跑道能见度随之下降。

An Analysis on Heavy Fog in Mianyang Airport

In this article we analyzed the cause and the process of a heavy fog in Mianyang airport which occurred in December,based on the routine observation data、the data from automatic weather station and the NCEP/NCAR 2.5°×2.5 grid point data and came to a conclusion as： the weak high pressure ridge at upper levels and the mean pressure field provided the good circulation background of this heavy fog;the favorable condition for the occurrence of this heavy frog was due to the sufficient supply of water vapor and the apparent inversion layer in middle and low level;divergence and subsidence in middle and low level helped the water vapor converged and prevented the diffusion of water vapor at initiation;it was found that there was an area of weak divergence and subsidence below 600hPa during the period of duration and an area of weak convergence ascending below 600hPa during the period of dissipation,and we found that the changes of the divergence field was very useful to analyze the initiation,duration and dissipation of the fog process.Also we found that microclimate environment of Mianyang airport caused the reducing of the runway visibility when wind direction changed from southwest or west to the southeast.