【摘要】 利用NCEP再分析格点资料、常规观测资料,统计分析了2005-2007年7-9月河北省典型的10次空气污染过程与气象要素、天气系统的关系。结果表明:河北省夏季典型污染过程的主要天气类型与冬季环流形式差别较大,可分为纬向型、低压槽前型、副热带高压外围型等;空气污染过程发生日多以雾、霾天气为主,05:00-08:00时(北京时)的能见度最小,地面观测资料的温度露点差(T-T_d)小于等于3℃;高空无明显的垂直运动或系统性弱下沉运动,近地层弱气压场、风场,不利于空气中污染物的扩散;近地层存在逆温,稳定的层结使空气污染得以持续;过程后期,因冷空气活动产生降水,空气污染减弱、结束。更多还原

【Abstract】 The relationship of air pollution with meteorological factors and weather systems for 10 typical cases in summer(July to September) from 2005 to 2007 in Hebei Province is analyzed by using the conventional observation data and NECP six-hour re-analysis data.It is concluded that the main weather patterns related to the typical processes of air pollution are longitudinal,frontal low trough,peripheral subtropical high patterns,etc.Air pollution occurs usually in fog and haze days,with minimum visibility between 05:00 and 20:00,and the dew-point deficit less than 3℃.There is no significant vertical motion or weak systematic downwelling at upper air.Because the weak pressure and wind fields near the surface are not conducive to the diffusion of contamination and the temperature inversion of the surface layer,the air pollutants are easily kept in the stable layer.When cold air invades,precipitation can make air pollution weaken or disappeared.更多还原