上海浦东机场平流雾的统计和监测分析

利用2000-2009年常规地面观测资料、探空资料和上海浦东机场地面气象例行观测资料,对浦东机场平流雾的气候特征和天气形势背景进行了统计分析.结果发现:浦东机场平流雾发生频次逐年增多、持续时间有增长趋势.从季节分布来看,平流雾多集中在冬春季出现.平流雾天气多发于“入海高压后部”、“副高西北侧”、“低槽气旋”、“台风外围”和“高压前部”等五类特定天气形势背景下.天气系统在空间上的特定配置使暖湿气流得以稳定的流经浦东机场,是浦东机场平流雾形成的根本原因.此外,利用浦东机场2007-2009年自动气象观测系统时间分辨率为1 min的能见度探测资料,对能见度低于200 m的平流浓雾进行分析,结果表明:浓雾爆发不是一次性完成的,稳定的浓雾形成之前会有较长时间的能见度大幅振荡过程,在能见度图谱上形成明显的“象鼻形”先期振荡特征,这一特性也给平流浓雾的监测和预警提供了依据.

Statistics and monitoring analysis of advection fog at Shanghai Pudong Airport

Using regular ground observations, sounding data, Shanghai Pudong Airport routine surface meteorological observations, statistic analysis of the climatic characteristics and the weather situations of advection fog at Pudong Airport has been carried out. The study found that advection fogs at Pudong Airport occur more and last longer year by year, mainly concentrate in winter and spring, appear at anytime in a day, mostly are southeast surface wind, and mainly occur in five specific weather situations which are "behind the high-pressure system entering the sea", "at the northwest side of the subtropical", "before the cyclone", "outside the typhoon", "before the high-pressure system". Using the visibility data with time resolution of one minute from Pudong airport Automatic Weather Observation System(AWOS) 2007-2009, the heavy advection fogs with visibility below 200 meters were analyzed. The results found that a number of proccesses are necessary for the outbreak of a heavy fog event. Before the main body of heavy advection fog's coming, there is a large-amplitude oscillation which shows obvious "trunk-like" fluctuating forepart at the visibility map. This feature provides a basis for monitoring and warning of advection fog.