The background condition, Temperature, visibility and stratification condition of fog happened on January 1st, 2015 was analyzed using conventional observation data from automatic weather stations(AWS), AWOS, airport wind profile radar, satellite cloud pictures. It is showed that, this fog process occurred and maintained in the atmospheric circulation background of warm ridge in high level, stable dry-warm southeast wind in lower layers, and cold-wet air mass behind the bottom of cold high near land surface, the structure of which provide a favorable necessities for the build-up and maintain of dense fog. This fog process is characterized with large spatial range with great depth, which covered the whole region along the northern slope of the Tianshan Mountains. The daily variation of air temperature over 2m altitude in the fog process is quiet small, with the air mass in fog saturated for a long time, which is also the main causes for the long time-period maintenance of the selected fog process.%利用常规观测资料、机场跑道自动观测系统(AWOS)、机场风廓线雷达、卫星云图等资料,分析2015年1月14日乌鲁木齐国际机场一次严重影响航班运行的大雾天气背景、温度、能见度、层结条件等.结果表明:此次大雾天气是在高空暖高压脊,低层干暖的东南风稳定维持,近地层处于地面冷高压底后部的冷湿气团控制的环流背景下形成的,上暖下冷的层结条件有利于逆温层的建立和维持,为大雾提供了必要条件.此次过程乌鲁木齐以西的北疆沿天山一带均为大雾天气所覆盖,大雾天气的范围大,厚度厚,且大雾期间各站的温度日变化很小,湿空气长时间维持饱和状态,也是乌鲁木齐机场大雾长时间维持的主要原因.
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