Long-Term Variation in Wintertime Atmospheric Diffusion Conditions Over the Sichuan Basin

Atmospheric diffusion is one of the factors affecting local air quality, dominating the evolution of air pollution episodes. Previous work has emphasized the unfavorable diffusion conditions in the Sichuan Basin resulting from its complex terrain. However, the recent spatiotemporal variation in atmo...

Descripción completa

Guardado en:
Detalles Bibliográficos
Autores principales: Guoyin Wang, Wennan Leng, Shaojing Jiang, Bangjun Cao
Formato: article
Lenguaje:EN
Publicado: Frontiers Media S.A. 2021
Materias:
Acceso en línea:https://doaj.org/article/77c327e5918640ecb2cd1b3b2eec753f
Etiquetas: Agregar Etiqueta
Sin Etiquetas, Sea el primero en etiquetar este registro!
id oai:doaj.org-article:77c327e5918640ecb2cd1b3b2eec753f
record_format dspace
spelling oai:doaj.org-article:77c327e5918640ecb2cd1b3b2eec753f2021-11-10T09:15:58ZLong-Term Variation in Wintertime Atmospheric Diffusion Conditions Over the Sichuan Basin2296-665X10.3389/fenvs.2021.763504https://doaj.org/article/77c327e5918640ecb2cd1b3b2eec753f2021-11-01T00:00:00Zhttps://www.frontiersin.org/articles/10.3389/fenvs.2021.763504/fullhttps://doaj.org/toc/2296-665XAtmospheric diffusion is one of the factors affecting local air quality, dominating the evolution of air pollution episodes. Previous work has emphasized the unfavorable diffusion conditions in the Sichuan Basin resulting from its complex terrain. However, the recent spatiotemporal variation in atmospheric diffusion conditions in the basin and their effects on local air quality remain unclear. Based on the wind speed, boundary layer height, vertical potential temperature difference of ERA5 analysis, two independent metrics containing information on horizontal and vertical diffusion ability, i.e., ventilation coefficient (VE) and the air stagnant conditions (ASI), are involved to indicate wintertime atmospheric diffusion conditions in the basin. Both VE and ASI reveal a decrease tendency of atmospheric diffusion condition from the northwestern portion of the basin to the southeast. In terms of the long-term variation in diffusion conditions, VE showed a broader increasing trend from 1979 to 2019, with a distinct increase in the western region. In contrast, the occurrence of air stagnation events has declined −3∼−6%/decade in the basin, more significantly over the western basin. Both the increase in VE and the decrease in air stagnation frequency indicate the improvement of atmospheric diffusion conditions in the Sichuan Basin from 1979 to 2019, which mitigates the effects of air pollutant emissions to some extent. The enhancement of diffusion conditions is due to the improvement of vertical diffusion conditions. The lowest seasonal PM2.5 concentrations occur in the northwestern basin, where VE is highest and ASI is lowest. Atmospheric diffusion conditions can explain approximately 25–50% of the interannual variation in PM2.5 concentrations in Chengdu.Guoyin WangGuoyin WangWennan LengShaojing JiangBangjun CaoFrontiers Media S.A.articleatmospheric diffusion abilityventilation coefficientatmospheric boundary layerair pollutionSichuan BasinEnvironmental sciencesGE1-350ENFrontiers in Environmental Science, Vol 9 (2021)
institution DOAJ
collection DOAJ
language EN
topic atmospheric diffusion ability
ventilation coefficient
atmospheric boundary layer
air pollution
Sichuan Basin
Environmental sciences
GE1-350
spellingShingle atmospheric diffusion ability
ventilation coefficient
atmospheric boundary layer
air pollution
Sichuan Basin
Environmental sciences
GE1-350
Guoyin Wang
Guoyin Wang
Wennan Leng
Shaojing Jiang
Bangjun Cao
Long-Term Variation in Wintertime Atmospheric Diffusion Conditions Over the Sichuan Basin
description Atmospheric diffusion is one of the factors affecting local air quality, dominating the evolution of air pollution episodes. Previous work has emphasized the unfavorable diffusion conditions in the Sichuan Basin resulting from its complex terrain. However, the recent spatiotemporal variation in atmospheric diffusion conditions in the basin and their effects on local air quality remain unclear. Based on the wind speed, boundary layer height, vertical potential temperature difference of ERA5 analysis, two independent metrics containing information on horizontal and vertical diffusion ability, i.e., ventilation coefficient (VE) and the air stagnant conditions (ASI), are involved to indicate wintertime atmospheric diffusion conditions in the basin. Both VE and ASI reveal a decrease tendency of atmospheric diffusion condition from the northwestern portion of the basin to the southeast. In terms of the long-term variation in diffusion conditions, VE showed a broader increasing trend from 1979 to 2019, with a distinct increase in the western region. In contrast, the occurrence of air stagnation events has declined −3∼−6%/decade in the basin, more significantly over the western basin. Both the increase in VE and the decrease in air stagnation frequency indicate the improvement of atmospheric diffusion conditions in the Sichuan Basin from 1979 to 2019, which mitigates the effects of air pollutant emissions to some extent. The enhancement of diffusion conditions is due to the improvement of vertical diffusion conditions. The lowest seasonal PM2.5 concentrations occur in the northwestern basin, where VE is highest and ASI is lowest. Atmospheric diffusion conditions can explain approximately 25–50% of the interannual variation in PM2.5 concentrations in Chengdu.
format article
author Guoyin Wang
Guoyin Wang
Wennan Leng
Shaojing Jiang
Bangjun Cao
author_facet Guoyin Wang
Guoyin Wang
Wennan Leng
Shaojing Jiang
Bangjun Cao
author_sort Guoyin Wang
title Long-Term Variation in Wintertime Atmospheric Diffusion Conditions Over the Sichuan Basin
title_short Long-Term Variation in Wintertime Atmospheric Diffusion Conditions Over the Sichuan Basin
title_full Long-Term Variation in Wintertime Atmospheric Diffusion Conditions Over the Sichuan Basin
title_fullStr Long-Term Variation in Wintertime Atmospheric Diffusion Conditions Over the Sichuan Basin
title_full_unstemmed Long-Term Variation in Wintertime Atmospheric Diffusion Conditions Over the Sichuan Basin
title_sort long-term variation in wintertime atmospheric diffusion conditions over the sichuan basin
publisher Frontiers Media S.A.
publishDate 2021
url https://doaj.org/article/77c327e5918640ecb2cd1b3b2eec753f
work_keys_str_mv AT guoyinwang longtermvariationinwintertimeatmosphericdiffusionconditionsoverthesichuanbasin
AT guoyinwang longtermvariationinwintertimeatmosphericdiffusionconditionsoverthesichuanbasin
AT wennanleng longtermvariationinwintertimeatmosphericdiffusionconditionsoverthesichuanbasin
AT shaojingjiang longtermvariationinwintertimeatmosphericdiffusionconditionsoverthesichuanbasin
AT bangjuncao longtermvariationinwintertimeatmosphericdiffusionconditionsoverthesichuanbasin
_version_ 1718440207912534016