[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"doc-detail-150437-en":3,"doc-seo-150437-105":30,"detail-sidebar-cat-0-en-105":91},{"code":4,"msg":5,"data":6},0,"success",{"doc_id":7,"user_id":8,"nickname":9,"user_avatar":10,"doc_module":4,"category_id":11,"category_name":12,"doc_title":13,"doc_description":14,"doc_content":15,"file_id":16,"file_url":17,"file_type":18,"file_size":19,"view_count":20,"is_deleted":4,"is_public":20,"is_downloadable":20,"audit_status":20,"page_count":21,"language":22,"language_code":23,"site_id":24,"html_lang":23,"table_of_contents":25,"faqs":26,"seo_title":27,"seo_description":14,"update_tm":28,"read_time":29},150437,8796093062539,"8796093062539","",8,"Research & Report","Elevated 3D structures of PM2.5 and impact of complex terrain-forcing circulations on heavy haze pollution over Sichuan Basin, China","Deep basins create uniquely favorable conditions for air pollution, and the Sichuan Basin in Southwest China is characterized by frequent heavy haze events. Using conventional and intensive observations together with the WRF-Chem model, the study investigates the 3D distribution of PM2.5 and links it to regional emissions, basin-associated circulations influenced by surrounding plateaus, and downwind transport. Results reveal a hollow–sandwiched vertical structure with high PM2.5 layers and a highly polluted near-surface layer, driven by lee vortex formation and vertical lifting out of the basin.","Please note the remarks at the end of the manuscript.  \nAtmos. Chem. Phys., 21, 1–16, 2021  \n[https://doi.org/10.5194/acp-21-1-2021](https://doi.org/10.5194/acp-21-1-2021)[ ](https://doi.org/10.5194/acp-21-1-2021)© Author(s) 2021 . This work is distributed under the Creative Commons Attribution 4 .0 License.  \nElevated 3D structures of PM2:5 and impact of complex terrain-forcing circulations on heavy haze pollution over Sichuan Basin, China  \nZhuozhi Shu 1,4 , Yubao Liu 1,4 , Tianliang Zhao 1,4 , Junrong Xia 1 , Chenggang Wang 1 , Le Cao 1 , Haoliang Wang 1 , Lei Zhang2 , Yu Zheng2 , Lijuan Shen 1 , Lei Luo3 , and Yueqing Li3  \n1 Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science and Technology, Nanjing, 210044, China  \n2 State Key Laboratory of Severe Weather & Key Laboratory of Atmospheric Chemistry of CMA, Chinese Academy of Meteorological Sciences, Beijing, 100081, China TS1  \n3Institute of Plateau Meteorology, China Meteorological Administration, Chengdu, 610072, China  \n4Precision Regional Earth Modeling and Information Center, Nanjing University of Information Science and Technology, Nanjing, 210044, China  \nCorrespondence: Tianliang Zhao ([tlzhao@nuist.edu.cn](tlzhao@nuist.edu.cn))  \nReceived: 6 November 2020 – Discussion started: 23 November 2020 Revised: 18 April 2021 – Accepted: 5 May 2021 – Published:  \nAbstract. Deep basins create uniquely favorable conditions for causing air pollution, and the Sichuan Basin (SCB) in Southwest China is such a basin featuring frequent heavy pollution. A wintertime heavy haze pollution event in the 5 SCB was studied with conventional and intensive observation data and the WRF-Chem model to explore the 3D distribution of PM2:5 to understand the impact of regional pollutant emissions, basin circulations associated with plateaus, and downwind transport to the adjacent areas. It was found 10 that the vertical structure of PM2:5 over the SCB was characterized by a remarkable hollow sandwiched by high PM 2:5 layers at heights of 1.5–3 km and a highly polluted nearsurface layer. The southwesterlies over the Tibetan Plateau (TP) and Yunnan-Guizhou Plateau (YGP) resulted in a lee 15 vortex over the SCB, which helped form and maintain heavy PM2:5 pollution. The basin PM2:5 was lifted into the free troposphere and transported outside of the SCB. At the bottom of the SCB, high PM 2:5 concentrations were mostly located in the northwestern and southern regions. Due to the blocking 20 effect of the plateau terrain on the northeasterly winds, PM 2:5 gradually increased from northeast to southwest in the basin. In the lower free troposphere, the high PM 2:5 centers were distributed over the northwestern and southwestern SCB areas, as well as the central SCB region. For this event, the  \nregional emissions from the SCB contributed 75.4 %–94.6 % 25 to the surface PM2:5 concentrations in the SCB. The SCBemissions were the major source of PM 2:5 over the eastern regions of the TP and the northern regions of the YGP, with contribution rates of 72.7 % and 70.5 %, respectively, during the dissipation stage of heavy air pollution over the SCB, 30 which was regarded as the major pollutant source affecting atmospheric environment changes in Southwest China.  \n1 Introduction  \nHaze pollution has caused serious environmental problems, especially in the densely populated and economically devel- 35 oped regions in China, which have high levels of fine particulate matter (PM 2:5) (particulate matter with an aerodynamic diameter equal to or less than 2.5 µm) (Guo et al., 2014; P. Liet al., 2015; Gu and Yim, 2016; Lin et al., 2018) . Owing to the significant adverse effects on human health and climate 40 change (Dawson et al., 2007; Langrish et al., 2012; Megaritiset al., 2014; Guo et al., 2016), understanding PM 2:5 pollution distributions and mechanisms","cbCaibvj1wRLZEOV","https://ap.wps.com/l/cbCaibvj1wRLZEOV","pdf",8795363,1,17,"English","en",105,"# Abstract\n# Introduction\n## PM2.5 haze pollution background and health/climate relevance\n## Regional hotspots and the Sichuan Basin research gap\n## Plateau “harbor effect” and lee-side stagnation mechanisms","[{\"question\":\"What modeling and observational approach is used to study the haze event?\",\"answer\":\"The study combines conventional and intensive observation data with the WRF-Chem model to analyze the 3D PM2.5 distribution over the Sichuan Basin.\"},{\"question\":\"How is the vertical structure of PM2.5 over the Sichuan Basin characterized?\",\"answer\":\"It features a hollow sandwiched by high-PM2.5 layers at heights of about 1.5–3 km, together with a highly polluted near-surface layer.\"},{\"question\":\"What role does terrain and plateau circulation play in heavy haze over the basin?\",\"answer\":\"Southwesterlies over the Tibetan Plateau and Yunnan–Guizhou Plateau produce a lee vortex over the Sichuan Basin, helping form and maintain heavy PM2.5 pollution, while basin PM2.5 can be lifted to the free troposphere and transported outward.\"}]","Elevated 3D structures of PM2.5 and impact of complex terrain-forcing circulations on heavy haze pollution over Sichuan Basin, China | PDF",1787820480,43,{"code":4,"msg":31,"data":32},"ok",{"site_id":24,"language":23,"slug":33,"title":13,"keywords":10,"description":14,"schema_data":34,"social_meta":86,"head_meta":88,"extra_data":90,"updated_unix":28},"elevated-3d-structures-of-pm25-and-impact-of-complex-terrain-forcing-circulations-on-heavy-haze-pollution-over-sichuan-basin-china",{"@graph":35,"@context":85},[36,53,68],{"@type":37,"itemListElement":38},"BreadcrumbList",[39,43,47,50],{"item":40,"name":41,"@type":42,"position":20},"https://docshare.wps.com","Home","ListItem",{"item":44,"name":45,"@type":42,"position":46},"https://docshare.wps.com/document/","Document",2,{"item":48,"name":12,"@type":42,"position":49},"https://docshare.wps.com/document/research-report/",3,{"item":51,"name":13,"@type":42,"position":52},"https://docshare.wps.com/document/elevated-3d-structures-of-pm25-and-impact-of-complex-terrain-forcing-circulations-on-heavy-haze-pollution-over-sichuan-basin-china/150437/",4,{"url":51,"name":13,"@type":54,"author":55,"headline":13,"publisher":57,"fileFormat":60,"inLanguage":23,"description":14,"dateModified":61,"datePublished":62,"encodingFormat":60,"isAccessibleForFree":63,"interactionStatistic":64},"DigitalDocument",{"name":9,"@type":56},"Person",{"url":40,"name":58,"@type":59},"DocShare","Organization","application/pdf","2026-09-04","2026-08-27",true,{"@type":65,"interactionType":66,"userInteractionCount":20},"InteractionCounter",{"@type":67},"ViewAction",{"@type":69,"mainEntity":70},"FAQPage",[71,77,81],{"name":72,"@type":73,"acceptedAnswer":74},"What modeling and observational approach is used to study the haze event?","Question",{"text":75,"@type":76},"The study combines conventional and intensive observation data with the WRF-Chem model to analyze the 3D PM2.5 distribution over the Sichuan Basin.","Answer",{"name":78,"@type":73,"acceptedAnswer":79},"How is the vertical structure of PM2.5 over the Sichuan Basin characterized?",{"text":80,"@type":76},"It features a hollow sandwiched by high-PM2.5 layers at heights of about 1.5–3 km, together with a highly polluted near-surface layer.",{"name":82,"@type":73,"acceptedAnswer":83},"What role does terrain and plateau circulation play in heavy haze over the basin?",{"text":84,"@type":76},"Southwesterlies over the Tibetan Plateau and Yunnan–Guizhou Plateau produce a lee vortex over the Sichuan Basin, helping form and maintain heavy PM2.5 pollution, while basin PM2.5 can be lifted to the free troposphere and transported 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