双流机场一次低能见度事件的气象分析
Meteorological Analysis of a Low Visibility Event at Shuangliu Airport

低能见度在交通运输方面影响较大，随着民航事业的高速发展，能见度预报越来越重要。本文利用常规气象观测数据，对发生在2015年1月12日的双流机场的大雾天气过程，通过分析此次大雾发生前的环流形势、气象要素、物理量以及层结条件等，得到以下结论：此次低能见度事件为辐射雾引发的。发生大雾前一晚的高空500 hPa为强的西北气流控制，中低层均为反气旋性流场，受冷空气影响，辐散下沉运动明显，从地面到925 hPa有一浅的逆温层，抑制垂直扩散，有利于晴空辐射冷却，并抑制对流的形成。同时低层相对湿度增大到>90%，气压逐渐增大，地面温度明显下降，导致水汽凝结，维持静风条件，风力大小<2 m/s，微弱风场使水汽凝聚在盆地内，另外，大雾发生前的大气层结稳定维持，且当天浅层有一些不稳定能量的增加，出现了微弱扰动，可促进雾滴碰并增长，这些均有利于大雾天气的产生。再加上盆地地形的协同作用，导致雾持续。通过对这次双流机场低能见度事件的细致分析，有利于对双流机场低能见度的成因有了进一步的深入了解，为民航精细化预报提供一定的科学依据。
Low visibility conditions significantly impact transportation systems. With the rapid development of civil aviation, visibility forecasting has become increasingly important. This study utilizes conventional meteorological observation data to analyze a heavy fog event at Shuangliu Airport on January 12, 2015. By examining the circulation patterns, meteorological elements, physical parameters, and atmospheric stratification conditions prior to the fog formation, the following conclusions were drawn: The low visibility event was triggered by radiation fog. The night before the fog occurred, the upper atmosphere at 500 hPa was dominated by strong northwesterly airflow, while the middle and lower layers exhibited anticyclonic flow patterns. Influenced by cold air, pronounced divergence and subsidence motions were observed. A shallow inversion layer extended from the surface to 925 hPa, suppressing vertical diffusion and favoring clear-sky radiative cooling while inhibiting convective development. Simultaneously, the relative humidity in the lower atmosphere increased to >90%, with gradually rising surface pressure and significant temperature drops that promoted water vapor condensation. Persistent calm wind conditions (<2 m/s) allowed moisture to accumulate within the basin. Additionally, the stable atmospheric stratification preceding the fog event, coupled with slight increases in unstable energy and weak disturbances in shallow layers, facilitated fog droplet coalescence and growth—all conducive to heavy fog formation. The basin’s topographic effects further contributed to the fog’s persistence. Through detailed analysis of this low visibility event at Shuangliu Airport, we gained deeper insights into the causative mechanisms, providing valuable scientific references for refined aviation weather forecasting.