广汉机场一次非典型辐射平流雾的天气诊断分析

Diagnostic Study on a Non-typical Radiation and Advection Fog in Guanghan Airport

为探索广汉机场雾发生发展的机制,确保飞行安全,提高预报准确率,利用广汉机场地面观测资料、Micaps系统下的常规观测资料、探空资料和NCEP/NCAR再分析资料,采用天气诊断分析方法,对2012年11月13日-15日广汉机场持续性的辐射平流雾进行分析。结果表明,雾是在稳定的天气背景下形成。夜间地面长波辐射冷却触发了这次雾的形成,而在轻雾转大雾期间,地面长波辐射冷却作用明显减弱,低层暖湿平流则起到了主要作用。与典型辐射平流雾不同的是成雾后,机场由脊前西北气流转为南支槽前西南气流控制,天空中云量的迅速增加使得雾进一步加强。

In order to find out the development mechanism of fog in Guanghan Airport and assure the safety of flight, improve the accuracy of forecasting, with observation data in Guanghan Airport, conventional data and sounding data of Micaps and NCEP/NCAR reanalysis data, the process of a long-lasting fog in Guanghan Airport that occurred dur- ing 13 and 15 November 2012 are analyzed by synoptic method. Results show that the fog was a non-typlcal radiation and advection fog, which occurred in the stable large-scale circulation. The cooling process produced by net surface radiation fluxes in night played a key role in the formation of the fog. During the process from light fog to dense fog, the role of cooling process produced by net surface radiation fluxes weakened, the warm and moist advection in lower level was responsible for the thickening of the fog. Different from typical radiation and advection fog, under the back- ground of south trough, the swiftly cloud increase in the sky played an important role in the maintenance of the dense fo~.