影响汾渭平原地区空气污染的地面环流形势及PM_(2.5)浓度预报研究  

The Impact of Surface Synoptic Circulation Types on Air Quality and the PM_(2.5) Concentration Forecast in Fen-Wei Plains

作　　者：刘慧 张煦庭 黄鑫 胡波[4] LIU Hui;ZHANG Xuting;HUANG Xin;HU Bo(Shaanxi Meteorological Observatory,Xi’an 710014,Shaanxi,China;Key Laboratory of Eco-Environment and Meteorology for the Qinling Mountains and Loess Plateau,Xi’an 710014,Shaanxi,China;Shaanxi Meteorological Information Center,Xi’an 710014,Shaanxi,China;State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China)

机构地区：[1]陕西省气象台,陕西西安710014 [2]秦岭和黄土高原生态环境气象重点实验室,陕西西安710014 [3]陕西省气象信息中心,陕西西安710014 [4]中国科学院大气物理研究所大气边界层物理和大气化学国家重点实验室,北京100029

出　　处：《高原气象》2022年第6期1583-1598,共16页Plateau Meteorology

基　　金：陕西省气象局秦岭和黄土高原生态环境气象重点实验室开放研究基金课题(2019M-11,2021G-15);陕西省自然科学基础研究计划项目(2022JQ-294,2020JQ-977,2021JQ-965)。

摘　　要：基于2014-2018年海平面气压资料,采用Lamb-Jenkinson(L-J)客观环流分型方法对影响汾渭平原地区的环流形势进行分型,分析PM_(2.5)污染季影响汾渭平原地区的主要环流形势。结合地面空气质量及气象要素观测资料探讨环流型与PM_(2.5)浓度及气象要素之间的关系,建立每种环流型下各地市的PM_(2.5)浓度预报模型。结果表明:(1)不同环流型出现的频率不同,且各环流型控制下PM_(2.5)浓度有所差异,其中偏南气流型(S)、东南气流型(SE)、偏东气流型(E)及气旋型(C)控制下PM_(2.5)污染日所占比例与所有环流型下PM_(2.5)污染日所占比例的比值均超过1,较易造成PM_(2.5)污染事件,同时这些环流型出现的频率与对应污染日数的乘积较大。(2)西安轻度及以上污染时混合层高度为483.5~601.38 m,相对湿度为42.94%~64.03%,风速为1.45~2.61 m·s^(-1),滞留指数为0.13~0.53。S型、SE型、E型及C型四种环流型下混合层高度平均值为488.98 m,风速平均值为1.89 m·s^(-1),滞留指数平均值为0.46,除C型外其余三个环流型控制时混合层高度低于500 m,风速低于2 m·s^(-1)及滞留指数大于0.4的站点数均超过60%,相对湿度高于60%的站点数超过50%。(3)2014-2018年所有环流型下计算等级与实测等级相差0~1级的样本数达82%,其中有37%的样本数计算等级与实测等级一致。2019-2020年预报值相对于实测值一致偏高,平均绝对偏差值与2014-2018年数值相差较小,模型的预报效果及稳定性较好。2019-2020年预报等级与实测等级相差0~1级的总样本数达80%,其中0级占33%。Based on the sea level pressure data from 2014 to 2018,Lamb-Jenkinson(L-J)atmospheric circulation classification scheme was used to classify the surface synoptic circulation types during air pollution seasons in Fen-Wei Plains and their relationships with the PM_(2.5)concentration and surface meteorological elements were analyzed.Combining the observed PM_(2.5)mass concentration and mixing layer height,relative humidity,wind speed,retention index,a PM_(2.5)concentration forecast model was established in each city under different surface synoptic circulation types.The results show:(1)Occurrence frequencies of different surface circulation types vary,under which the distributions of PM_(2.5)concentration and meteorological elements differentiate also.Under controls of circulation types South(S),South East(SE),East(E)and cyclone(C)the ratio of PM_(2.5)polluted days proportion to PM_(2.5)polluted days proportion under all synoptic circulation types were more than 1,corresponding to a larger product of the occurrence frequency and the pollution days,which will lead to PM_(2.5)pollution events easily.(2)In the case of mild or above pollution in Xi’an,the mixed layer height ranged from 483.5m to 601.38 m,the relative humidity ranged from 42.94%to 64.03%,the wind speed ranged from 1.45 m·s^(-1)to 2.61 m·s^(-1)and the retention index ranged from 0.13 to 0.53.Under controls of circulation types S,SE,E and C the average mixed layer height was 488.98 m,the average wind speed was 1.89 m·s^(-1)and the average retention index was 0.46.Except for under type C,the mixed layer height was below 500 m on more than 60%of the sites,and the relative humidity over 60%on more than 50%of the sites.The wind speed was below 2 m·s^(-1)with a retention index more than 0.4 on more than 60%of the sites under all four circulation types.(3)According to the PM_(2.5)concentration forecast models for different circulation patterns in each city,there exists a 0~1 level difference between predicted level and measured level about 82%of all sample

关 键 词：环流分型 PM_(2.5)质量浓度 气象要素 预报模型 

分 类 号：X16[环境科学与工程—环境科学]