河北平原一次持续大雾天气分析  

Analysis on a Heavy Fog Event in Hebei Plain

作　　者：侯瑞钦 李江波 赵玉广 

机构地区：[1]河北省气象局,河北石家庄050021

出　　处：《干旱气象》2009年第3期263-270,共8页Journal of Arid Meteorology

基　　金：中国气象局新技术推广项目"河北平原大雾能见度与生消时间预报系统研发"资助

摘　　要：利用气象观测资料和NCEP 1°×1°资料，从天气背景、温湿特征、层结条件、动力热力学特征等方面分析了2007年11月7～13日河北平原1次持续大雾的成因。结果表明：这次大雾是在较为稳定的大气环流背景下产生的，中高层以纬向环流为主，冷空气以扩散形势影响华北地区；地面夜间风速在0～2m／s，充足的水汽及地面辐射冷却作用有利于大雾的形成和维持；大气层结是对流稳定的，同时近地面层为逆温结构；近地面层的弱辐合及持续微弱的暖平流十分有利于逆温层的维持，对于大雾长时间维持具有重要作用。大雾多发生在地面辐合线偏向冷空气一侧。本次大雾性质复杂，持续大雾由平流辐射雾-辐射雾-平流雾3个阶段构成，不同阶段大雾逆温强度及湿层厚度有所不同。Based on the observations and the NCEP reanalysis data, a heavy fog event occurred in Hebei Plain from November 7 to 13, 2007 is investigated from such aspects as the weather background, temperature and humidity condition, the atmospheric stratification, dynamic and thermal features. The results show that the background situation was stable with zonal circulation at the middle and high levels and no strong cold air moving during the heavy fog. The ground wind speed at night ranged from 0 to 2 m/s. Plenty vapor and radiation cooling process at ground layer were in favor of the formation and maintenance of the heavy fog. The atmospheric stratification was stable with an inversion layer near the ground, and the weak convergence and the persistent warm advection near the ground made for maintaining of the inversion layer, which played a very important role in the long -time maintenance of the fog event. The heavy fog event went through three phases including advection - radiation fog, radiation fog and advection fog, and the intensity of ground invertion and moist thickness were different in different developing phases of the fog.

关 键 词：大雾 天气分析 辐射 逆温层 

分 类 号：P458.3[天文地球—大气科学及气象学]