北京一次雾霾天气的气象条件和污染物输送特征分析  

Analysis of meteorological conditions and pollutant transport characteristics during haze days in Beijing

作　　者：姚爽 熊秋芬[2] 姜晓飞 张志森[1] YAO Shuang;XIONG Qiufen;JIANG Xiaofei;ZHANG Zhisen(National Meteorological Information Center,Beijing 100081,China;CMA Training Centre,Beijing 100081,China)

机构地区：[1]国家气象信息中心,北京100081 [2]中国气象局气象干部培训学院,北京100081

出　　处：《气象科学》2024年第5期928-935,共8页Journal of the Meteorological Sciences

基　　金：国家自然科学基金资助项目(U2033207);国家自然科学基金青年基金资助项目(41905053)。

摘　　要：利用气象常规观测资料以及国家环境监测站PM_(2.5)质量浓度资料,分析2019年3月1—6日北京持续性雾霾过程特征、环流形势和气象影响因子;再基于HYSPLIT模式,模拟过程期间北京近地层气团的后向轨迹;采用WRF-Chem对污染过程中PM_(2.5)输送通量进行模拟分析。结果表明,在整个污染过程中北京高空环流平直或受槽后西北气流控制,地面受弱高压或低压槽控制,风速较小,近地层逆温维持,气象条件不利于污染物扩散;PM_(2.5)质量浓度与地面风速、相对湿度变化明显相关,是影响PM_(2.5)质量浓度日变化的重要气象因子;除不利于本地污染扩散的气象条件外,HYSPLIT轨迹聚类结果显示,本次污染过程中有向北京的污染气团输送,以西南—东北向路径为主,此类轨迹占比大、PM_(2.5)平均质量浓度大,在污染输送中贡献最大;WRF-Chem模拟PM_(2.5)输送通量结果表明在整个污染过程中北京南侧和东侧有较大的PM_(2.5)输入通量,与轨迹模拟结果及北京东南部污染相对西北更重的观测实际基本一致。Based on conventional observation data,hourly observation data from automatic stations and the PM_(2.5)concentration data from environmental monitoring station,the circulation situation and meteorological factors of the haze days in Beijing from March 1 to 6,2019 was analyzed.Based on HYSPLIT model,the backward trajectory of near-surface air parcel in Beijing during the process was simulated.WRF-Chem model was used to simulate the PM_(2.5)transport flux during the pollution process.Results show that,during the whole pollution process,there are west airflow or northwest airflow at 500 hPa and weak anticyclone or low pressure at surface with small wind speed,and the temperature inversion layer nearsurface is sustained.These meteorological conditions are not favorable for the diffusion of pollutants.The correlation between concentration of PM_(2.5)and surface wind speed is negative,while the correlation between concentration of PM_(2.5)and relative humidity is positive.The diurnal variation of relative humidity and wind speed is coincided with the diurnal variation of concentration of PM_(2.5).The trajectory simulation shows that,in addition to the accumulation of local pollution under adverse meteorological conditions,the pollutant in Beijing is transported from southwest to northeast.This kind of air mass has the largest number of trajectories and the largest average concentration of PM_(2.5),which contributes most to the pollution process.The analysis of PM_(2.5)transport flux also shows that there is a large PM_(2.5)inflow flux from the south and east of Beijing during the pollution process.The result is consistent with the trajectory cluster,which confirmed that the pollution in the east and south of Beijing was significantly heavier than that in the northwest of Beijing.

关 键 词：PM_(2.5) 气象条件 轨迹 输送通量 质量浓度权重轨迹 

分 类 号：P425.55[天文地球—大气科学及气象学]