天津秋冬季重度霾天气过程气象特征分析及海风的作用

发布时间：2019-03-08 08:07

【摘要】：利用常规气象观测资料、加密自动站观测资料、污染物PM2.5质量浓度数据等,对近3年天津秋冬季出现的重度霾天气过程进行分析。主要从重度霾天气发生的天气形势、气象要素特征、减弱消散条件等方面进行分析。结果表明:秋冬季重度霾天气发生时500 h Pa环流形势基本为弱西北气流或偏西气流,低层850 h Pa为高压脊前偏北气流或暖高压脊或高压后部西南气流等控制;地面气压场较弱,多为鞍形场、低压或高压后部控制,风力较小。重度霾天气发生时,海平面气压值基本在1 023~1 028.5 h Pa之间,地面多为南到东南风,风速1.0 m/s,水平能见度较差(基本在2.0 km以下),当空气湿度较大、雾和霾同时存在时能见度会降至1.0 km以下,另外霾天气发生时在850 h Pa以下均存在较强逆温层或双层逆温现象。对于重度霾天气减弱消散条件,除冷空气东移南下能对污染物起到很好消除作用外,当地面西南风明显加大、出现浓雾天气近地层空气达到饱和以及受偏东路径冷空气影响时,也会对重度霾过程减弱消散起到较好的作用。另外受海风环流影响时,天津大气污染扩散条件会好转、污染物浓度降低、重度霾过程会减弱消散;但因存在海风锋锋前累积增长特征,受海风影响地区会出现霾污染加重的现象(一般为3 h左右,与海风强度及移动速度有关)。
[Abstract]:Using conventional meteorological observation data, encrypted automatic observation data and pollutant PM2.5 mass concentration data, the severe haze weather process in Tianjin in autumn and winter in recent 3 years was analyzed. Mainly from the severe haze weather situation, meteorological elements characteristics, weakening dissipative conditions and other aspects of the analysis. The results show that when the severe haze occurs in autumn and winter, the Pa circulation situation is basically weak northwest airflow or westward airflow, and the lower level 850h Pa is controlled by the northerly airflow in front of the high pressure ridge or warm high pressure ridge or the southwest airflow in the rear part of the high pressure. Ground air pressure field is weak, mostly saddle field, low pressure or high pressure rear control, small wind. When the severe haze occurs, the sea level pressure is basically between 1 023 and 1 028.5 h / Pa, the ground is mostly south to southeast wind, the wind speed is 1. 0m / s, the horizontal visibility is poor (basically below 2. 0 km), when the air humidity is higher, When fog and haze exist at the same time, visibility will decrease to less than 1.0 km. In addition, there is strong inversion layer or double layer inversion phenomenon when haze occurs below 850h / Pa. For the weakening and dissipating conditions of severe haze weather, except that the cold air moves eastward down to the south can play a very good role in eliminating pollutants, when the southwest wind on the ground is obviously increased, when the surface air reaches saturation in dense fog weather and is affected by the cold air in the eastward path, It will also play a good role in reducing and dissipating the severe haze process. In addition, under the influence of sea wind circulation, the diffusion conditions of air pollution in Tianjin will be improved, the concentration of pollutants will be reduced, and the process of heavy haze will be weakened and dissipated. However, due to the accumulated growth characteristics in front of the sea wind front, the haze pollution will increase in the areas affected by the sea wind (generally about 3 h, which is related to the intensity and velocity of the sea wind).
【作者单位】：天津市气象科学研究所;天津市气象台;
【基金】：天津市气象局课题(201609ybxm06) 科技支撑项目子课题(2014BAC23B01) 天津科委项目(14ZCDGSF00027)
【分类号】：X16;X513

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