荆州市大气污染物周边源影响域的气候模拟研究

以大气污染物协同控制与精准治理的需求为导向,开展湖北省荆州市大气污染物的来源分析.基于FLEXPART-WRF模式揭示了2008—2017年荆州市PM_2.5周边源"影响域"的季节气候特征,估算了大气污染物区域传输和局地排放的相对贡献,确定出不同季节的大气污染物主要传输通道.结果表明,荆州地区PM_2.5主要"影响域"为湖北、湖南、河南和安徽省.不同季节湖北省外源传输对荆州PM_2.5"影响域"的贡献率分别为春季50.4%、夏季33.9%、秋季42.6%、冬季43.0%和年均45.1%.春季3条区域传输通道分别为北通道（沿南阳盆地-荆州）、东通道（沿长江航道-荆州）以及南通道（沿雪峰山-荆州）;夏季主要为南通道;秋、冬季分别为北通道、东北通道（沿大别山低山丘陵-荆州）及东通道.针对荆州主要3类重污染天气型的典型个例"影响域"分析表明,高压静稳型PM_2.5污染主要来源于本地排放,省内贡献率达87.8%;低压倒槽型PM_2.5污染主要来源于偏南输送和本地累积,省内贡献率达55.0%;冷锋输送型PM_2.5污染主要来源于北路区域传输,省外贡献率达77.2%.对于冬季重污染期间,建议重点围绕荆州本地与省内荆门、襄阳、孝感、天门、潜江、武汉、随州、宜昌及省外常德、南阳、信阳等地开展协作,加强区域间大气污染联防联控.该项研究可为区域大气污染精细化管控与靶向治理提供科学依据.

Climate simulation on the influence domains of air pollutant sources for the urban area of Jingzhou

This study conducted the source analysis of atmospheric pollutants in the urban area of Jingzhou,Hubei province for the local environmental management and he precise pollution control.By using the model FLEXPART-WRF,the climatic characteristics of PM_2.5 concentrations over Jingzhou and its surrounding sources from 2008 to 2017 were investigated,the relative contributions of regional PM_2.5 transport and local emissions were evaluated,and the main transport pathways of PM_2.5 were identified in different seasons.The results showed that the main "influence source regions" of PM_2.5 for Jingzhou were located over Hubei,Hunan,Henan and Anhui provinces.The air pollutant sources beyond Hubei province had a greater impact on PM_2.5 over Jingzhou with spring,summer,autumn,winter and annual regional transport contribution rates of 45.1%,50.4%,33.9%,42.6% and 43.0%,respectively.The three major pathways of regional PM_2.5 transport in spring were characterized wih the northern channel across Nanyang Basin,the eastern channel along the Yangtze River Channel and the southern channel along Xuefeng Mountain-Jingzhou,respectively.In summer,the southern pathway was the main transport channel to Jingzhou.There were three regional transport channels of air pollutants in autumn and winter with the North Channel,the Northeast Channel,and the East Channel.Combined with the synoptic analysis of the "impact source regions" of heavy air pollution over Jingzhou,the main air pollutant sources of high-pressure stable type of PM_2.5 pollution were local emissions with the Hubei provincial contribution rate of 87.8%; the main sources of low-pressure for PM_2.5 pollution were regional transport from the south and local accumulation,the contribution in the province was up to 55.0%; the cold front transport type of PM_2.5 pollution was mainly from northern transport,and the contribution out of Hubei province was up to 77.2%.For the wintertime heavy air pollution,it is suggested to focus on the jiont control over Jingzhou and other cities such as Jingmen,Xiangyang,Xiaogan in Hubei province as well as cities like Changde,Nanyang,Xinyang in other provinces.This study provided a scientific basis for the refined management and targeted reduction of air pollutant emissions.