Atmospheric Environment最新文献

{"title":"Global evaluation of NOAA-20 VIIRS dark target aerosol products over land and ocean","authors":"Xin Pei,&nbsp;Leiku Yang,&nbsp;Weiqian Ji,&nbsp;Mengnan Li,&nbsp;Zhe Peng,&nbsp;Xiaoqian Cheng,&nbsp;Xiaofeng Lu","doi":"10.1016/j.atmosenv.2024.120949","DOIUrl":"10.1016/j.atmosenv.2024.120949","url":null,"abstract":"<div><div>The Dark Target (DT) algorithm has been applied to the Visible Infrared Imaging Radiometer Suite (VIIRS) aboard the Suomi-NPP (SNPP) and NOAA-20 satellites to extend the aerosol data record from the Moderate Resolution Imaging Spectrometer (MODIS). The newly released VIIRS DT Version 2.0 (V2.0) dataset includes NOAA-20 aerosol products for the first time. This study provides the first evaluation of NOAA-20 VIIRS DT aerosol products, including aerosol optical depth (AOD) and Ångstrom exponent (AE), for the period 2018–2022 using Aerosol Robotic Network (AERONET) and Maritime Aerosol Network (MAN) measurements. In addition, the operational DT aerosol products from SNPP VIIRS (V2.0) and MODIS (Collection 6.1) are also used for comparison purposes. Overall, NOAA-20 AODs over land and ocean exhibit good validation metrics globally, showing comparability to MODIS products and superiority over overestimated SNPP products. Nevertheless, it is worth noting that in South Africa specifically, NOAA-20 land AODs tends to display more pronounced negative biases, despite all products being underestimated. Furthermore, all ocean AE products demonstrate high correlation coefficients (&gt;0.83) with the ground-based data, meeting the fraction of expected accuracy (&gt;80%). Encouragingly, NOAA-20 AE product has significantly improved the persistent issue of overestimation at low-value in MODIS product, making it a more preferable choice for usage. Error analysis reveals that the performance of all three land products decreases in sparsely vegetated areas and when the solar zenith angle is small. However, NOAA-20 AOD exhibits relatively stable performance and is less affected by variations in aerosol loading, observation geometry, and surface vegetation cover. In addition, the performance of AOD and AE over ocean is significantly influenced by scattering angle and wind speed. This research is anticipated to serve as a reference for the utilization of operational VIIRS DT aerosol products and possible algorithm optimization.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"342 ","pages":"Article 120949"},"PeriodicalIF":4.2,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142744081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seasonal variation and inhalation health risk of atmospheric polyfluoroalkyl and perfluoroalkyl substances in a metropolitan city centre of southwest China","authors":"Hongtao Si ,&nbsp;Donghang Xie ,&nbsp;Fengwen Wang ,&nbsp;Mengbing Hao ,&nbsp;Jiaxin Liu ,&nbsp;Hai Guo ,&nbsp;Neil L. Rose","doi":"10.1016/j.atmosenv.2024.120950","DOIUrl":"10.1016/j.atmosenv.2024.120950","url":null,"abstract":"<div><div>Fifty-six total suspended particle (TSP) samples, covering four seasons from April 2022 to January 2023, were collected from the centre of Chongqing, a metropolitan city of southwest China, using an aerosol sampler. The samples were analyzed for 20 targeted poly- and per-fluoroalkyl substances (PFAS) by HPLC-MS/MS. The concentrations of PFAS ranged from 125 pg/m³ to 200 pg/m³ and were dominated by perfluorobutanoic acid (PFBA), perfluorooctanoic acid (PFOA), 2-perfluorohexyl ethanoic acid (6:2 FTCA) and perfluorooctane sulfonate (PFOS). Seasonal variations of PFAS were distinct, with the highest concentrations in winter, followed by autumn, and with lowest levels in summer. Positive matrix factorization (PMF) and a dry deposition model were used to apportion sources and to estimate the dry deposition fluxes of the 20 PFAS, respectively. PMF analysis indicated that, based on the annual average, paper packaging production (28.1%) and the degradation of precursor compounds and emissions from PFCA production (27.8%) were the two major sources, followed by electronic product manufacturing (24.0%) and textile production (20.1%), although there were significant differences in sources between seasons. The average annual dry deposition flux of PFAS was estimated to be 18.0 ng/m²/day. However, the wet deposition of PFAS was estimated to account for 82.2% of the total atmospheric deposition flux, suggesting it plays a more important role. Estimated daily intakes (EDI) and hazard quotients (HQ) were utilized to evaluate the risks to humans via exposure to PFAS through inhalation and were found to be insignificant (HQ ≪1). This study provides important information on the contamination status and exposure risk for atmospheric PFAS in a mountainous megacity, and for similar urban centers across China.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"342 ","pages":"Article 120950"},"PeriodicalIF":4.2,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142757630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling the impacts of open biomass burning on regional O3 and PM2.5 in Southeast Asia considering light absorption and photochemical bleaching of Brown carbon","authors":"Minsu Choi,&nbsp;Qi Ying","doi":"10.1016/j.atmosenv.2024.120942","DOIUrl":"10.1016/j.atmosenv.2024.120942","url":null,"abstract":"<div><div>Open biomass burning in Southeast Asia has significant adverse impacts on air quality in the region and in downwind areas. These biomass burning events emit large amounts of light absorbing brown carbon (BrC). Once in the atmosphere, the light absorbing capacity of BrC is reduced by various oxidation processes. However, few modeling studies have been conducted to explicitly examine light absorption and bleaching on the prediction of ozone (O₃) and fine particulate matter (PM_2.5). In this study, a modified Community Multiscale Air Quality (CMAQ) model that explicitly tracks the concentrations of light absorbing and non-light absorbing organic aerosol components from different emission sources and the bleaching of BrC due to photooxidation and OH oxidation is applied to widespread open biomass burning events in March 2018 in Southeast Asia. Open biomass burning accounts for as much as 20–40 ppb (30–50%) of the maximum daily average 8-h ozone (MDA8 O₃) and 40–120 μg m⁻³ (60–90%) of the daily average PM_2.5 in the emission source regions. Compared to a simulation without BrC light absorption, the predicted MDA8 O₃ and PM_2.5 are as much as 16 ppb and 16 μg m⁻³ lower, respectively, than a simulation with light absorption. This confirms that neglecting the UV light absorption of BrC can lead to significant overpredictions of O₃ and PM_2.5 during the open biomass burning periods, which may lead to an overestimation of the adverse impacts of biomass burning on public health in Southeast Asia. The addition of BrC bleaching results in a 0.5–1% increase in MDA8 O₃ and 1–5% increase in PM_2.5 compared to the case without BrC bleaching. The results of this study indicate that light absorption by BrC needs to be considered in chemical transport modeling of large open biomass burning events. The BrC bleaching process is relatively slow and neglecting this process does not significantly change the predictions of MDA8 O₃ and PM_2.5 during open biomass burning.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"342 ","pages":"Article 120942"},"PeriodicalIF":4.2,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multicity accountability and uncertainty assessment of the impacts of regulations on air quality in Atlanta, New York City, and Southern California","authors":"Ziqi Gao ,&nbsp;Eric J. Mei ,&nbsp;Xin He ,&nbsp;Philip K. Hopke ,&nbsp;Stefanie Ebelt ,&nbsp;David Q. Rich ,&nbsp;Armistead G. Russell","doi":"10.1016/j.atmosenv.2024.120947","DOIUrl":"10.1016/j.atmosenv.2024.120947","url":null,"abstract":"<div><div>Multiple regulations have been promulgated to improve air quality, and previous studies have used an accountability chain to evaluate the effects of these regulations on emission levels, air quality, and human health. However, quantifying these impacts through the accountability chain is complex due to interactions between multiple factors that can influence the efficacy of control policies and introduce uncertainties at each step. We evaluated and quantified the impact of emission controls on electricity generating units (EGU) and motor vehicle sources on emissions and air quality via Generalized Additive Models. These GAMs have minimal bias (around 10⁻⁵ to 10⁻² μg/m³ or ppbV) and r² values for daily concentrations ranging from 0.4 to 0.7 Counterfactual air pollutant concentrations, in the absence of EGU and mobile source regulations, were calculated using estimated counterfactual emissions for the period 2005 to 2019 in Atlanta, New York City, and California's South Coast Air Basin. Counterfactual air pollutant concentrations indicated that the effects of regulations on air pollutants varied depending on the season and location. Predicted counterfactual air pollutant concentrations were generally 2–12 times higher than the measured concentrations at these sites, except for ozone. The impact of regulations on ozone concentrations typically resulted in reduced peak ozone values in the summer, but increased concentrations in the winter. Monte Carlo modeling found small to modest uncertainties, depending on the pollutant, location and regulations assessed. Counterfactual concentrations predicted in this project will be used in the assessment of the trends of toxicity in PM_2.5.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"342 ","pages":"Article 120947"},"PeriodicalIF":4.2,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697731","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterizing indoor-outdoor PM2.5 concentrations using low-cost sensor measurements in residential homes in Dhaka, Bangladesh","authors":"Provat K. Saha ,&nbsp;Ahsan Habib ,&nbsp;Dipika R. Prapti ,&nbsp;Talha Jubair ,&nbsp;Abu U. Zarrah ,&nbsp;Chowdhury A. Hossain ,&nbsp;Sheikh M. Rahman ,&nbsp;Abdus Salam ,&nbsp;Md Aynul Bari ,&nbsp;Julian D. Marshall","doi":"10.1016/j.atmosenv.2024.120945","DOIUrl":"10.1016/j.atmosenv.2024.120945","url":null,"abstract":"<div><div>We collected simultaneous indoor and outdoor PM_2.5 measurements from 17 homes in Dhaka, Bangladesh, to characterize spatio-temporal variations and identify factors influencing indoor and outdoor PM_2.5 levels. A pair of PurpleAir PM_2.5 sensors were deployed at each home, one indoors and the other outdoors, during the wet and dry seasons, and the locally calibrated data were used for analysis. Indoor and outdoor PM_2.5 levels were three times higher during the dry season (indoor 146 ± 22 μg/m³, outdoor 153 ± 23 μg/m³) than during the wet season (indoor 52 ± 12 μg/m³, outdoor 50 ± 11 μg/m³). Indoor to outdoor (I/O) ratios were close to 1 in both seasons (dry: 0.97 ± 0.14, wet: 1.05 ± 0.19). This suggests that regional background pollution levels significantly influence indoor levels observed in different households. Infiltration factors closer to 1 (dry: 0.83 ± 0.12; wet: 0.87 ± 0.14), determined through mixed-effects regression of indoor and outdoor time series data, further highlight the substantial impact of outdoor pollution on indoor levels. Data from individual households exhibited strong temporal correlation between indoor and outdoor levels in both seasons (Pearson R: 0.82 ± 0.12 during the dry season and 0.83 ± 0.14 during the wet season), whereas indoor-outdoor spatial correlations across measured households were moderate (R: 0.49 and 0.62 during dry and wet seasons, respectively). These spatial correlations and empirical regression modeling suggest that while the spatial variation of outdoor PM_2.5 levels significantly influences indoor levels' spatial variation, other factors such as indoor source activities and ventilation-related features play crucial roles in explaining variabilities in indoor PM_2.5 across homes. Overall, our study suggests that indoor environments in Dhaka city are nearly as polluted as outdoor settings, and this locally derived scientific evidence can be valuable for enhancing public awareness and developing mitigation measures to reduce PM_2.5 exposures in Bangladesh.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"342 ","pages":"Article 120945"},"PeriodicalIF":4.2,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dust- versus cloud-radiation impacts on the diurnal temperature range for long-lasting dust weather over the Taklimakan Desert","authors":"Yong Chen ,&nbsp;Junling An ,&nbsp;Yu Qu ,&nbsp;Hong Wang","doi":"10.1016/j.atmosenv.2024.120946","DOIUrl":"10.1016/j.atmosenv.2024.120946","url":null,"abstract":"<div><div>The diurnal temperature range (DTR), determined by the difference between daily maximum and minimum air temperature, is an important index of global climate change. The dust direct radiative effect on DTR in cloudy conditions in the Taklimakan Desert (TD) area is still unclear. Based on springtime ground observation data from 2002 to 2013, the DTR variation in dust/cloudy days and the DTR-visibility relationship in dust days in TD were analyzed and summarized. The mean DTR was proportional to the mean visibility, with a slow DTR increase in the southwestern TD caused by cloud-induced radiation when visibility was 4–10 km; the DTR difference between cloudy and cloudless dust days was more significant (1.8–4.2 °C) when visibility was &gt;6 km. The simulation of a long-lasting dust-cloud coexisting event (4 days) with the factor separation technique showed that both pure dust- and cloud-radiation impacts reduced DTR but their synergistic radiation impact mostly increased DTR in TD. Both simulated and observed results indicated that when the daily visibility of dust weather increased from 4-6 km to 6–10 km, the important pure dust impact on DTR weakened whereas the cloud impact became significant.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"342 ","pages":"Article 120946"},"PeriodicalIF":4.2,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142744167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification of major sources of PM2.5 and gaseous pollutants contributing to oxidative potential in the Yeosu national petrochemical industrial complex: Insights from the PMF model","authors":"Seoyeong Choe,&nbsp;Geun-Hye Yu,&nbsp;Myoungki Song,&nbsp;Sea-Ho Oh,&nbsp;Hajeong Jeon,&nbsp;Dong-Hoon Ko,&nbsp;Chaehyeong Park,&nbsp;Min-Suk Bae","doi":"10.1016/j.atmosenv.2024.120943","DOIUrl":"10.1016/j.atmosenv.2024.120943","url":null,"abstract":"<div><div>This investigation seeks to characterize and pinpoint the sources of PM_2.5 and various gaseous pollutants within the Yeosu National Industrial Complex by employing the source apportionment model. PM_2.5 samples were gathered at 3-h intervals during various seasons using both quartz and Teflon filters, and subjected to chemical composition analysis. The mean PM_2.5 concentration was recorded at 22.8 μg/m³, with elevated levels observed during the winter. The source analysis delineated 5 p.m._2.5 sources, featuring combinations of EC, Pb, Ni, Cu, and OC. Gaseous pollutants were categorized into CO, CO₂, Chloroform, Isopropylbenzene &amp; Chlorobenzene, Dichlorobenzene, and Vehicle emissions. Conditional Probability Functions analysis revealed various source inflow directions, predominantly influenced by the nearby industrial complex. The dithiothreitol assay-oxidative potential normalized to 9,10-phenanthrenequinone (QDTT-OP) of PM_2.5 demonstrated significant correlations with primary emission sources, particularly EC and Pb, due to incomplete combustion processes. Effectively managing these emissions is essential for mitigating health risks related to air pollution. This research offers crucial information for the formulation of strategies aimed at enhancing air quality and public health in industrialized regions.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"342 ","pages":"Article 120943"},"PeriodicalIF":4.2,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sources and their contributions of ambient PM2.5 concentrations in an industrial area of Atlanta from 1998 to 2016","authors":"Ivana Stanimirova ,&nbsp;David Q. Rich ,&nbsp;Armistead G. Russell ,&nbsp;Philip K. Hopke","doi":"10.1016/j.atmosenv.2024.120944","DOIUrl":"10.1016/j.atmosenv.2024.120944","url":null,"abstract":"<div><div>The SouthEastern Aerosol Research CHaracterization (SEARCH) program examined air quality at 6 sites across the southeastern United States. The Jefferson Street site in Atlanta operated from 1998 to 2016 with the collection and chemical characterization of PM_2.5 that provide data suitable for source identification and apportionment with a sufficiently long time series to permit effective trend analyses. Although there have been analyses of parts of these data, there is no prior comprehensive analysis relating the changes in source-specific PM_2.5 with policy implementations and economic drivers. The major sources were secondary sulfate, traffic sources (spark- and compression-ignition vehicles), and secondary nitrate. Several local industrial sources were identified primarily assigned as metal working, but likely including a nearby bus maintenance garage. A combined biomass burning and pyrolyzed organic carbon factor was resolved that reflected the extensive prescribed burning that occurred in the southeastern United States to control larger wildfires and that increased in recent years. The major trends were reductions in concentrations of sulfate and nitrate likely as a result of policies to reduce emissions from coal-fired power plants and mobile sources. Gasoline vehicle contributions uniformly declined, but there was a period of increase diesel concentrations in the middle of the study period for which the cause is unknown.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"342 ","pages":"Article 120944"},"PeriodicalIF":4.2,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Canadian record-breaking wildfires in 2023 and their impact on US air quality","authors":"Han Chen ,&nbsp;Weihang Zhang ,&nbsp;Lifang Sheng","doi":"10.1016/j.atmosenv.2024.120941","DOIUrl":"10.1016/j.atmosenv.2024.120941","url":null,"abstract":"<div><div>In recent years, extreme climate has increasingly triggered record boreal wildfires. The year 2023 saw a significant surge in wildfire occurrences in Canada, far surpassing the historical record. In this study, multi-source data were utilized for a comprehensive analysis of the development of the Canadian wildfires in 2023, the pathways of wildfire smoke, and its impact on the air quality in the US. The results indicate that the 2023 Canadian wildfires mainly occurred in western Canada (accounting for 60% of the burned area) and Quebec (eastern Canada, 29% of the burned area). Weather systems played a key role throughout wildfires and smoke plume transport processes. Specifically, high temperatures and dry weather caused by the blocking high-pressure systems was conducive to the enhancement of wildfire activities. Additionally, the southward airflow ahead of the ridge facilitated the transport of wildfires plume towards the south. This transport pattern frequently manifests under the Weather Regimes (WR) associated with the Alaskan Ridge (AkR) and Arctic High (ArH). In May and July, the smoke originating from the wildfires in western Canada, guided by the North American trough, affected the midwestern US. In June, smoke from eastern Canada led to severe air pollution in the northeastern US. Throughout the wildfire season, particulate matter dominated pollution in the US. The daily average PM_2.5 concentration peaked at 258.9 μg/m³, exceeding the World Health Organization standard guidelines (15 μg/m³) by 17.3 times. This study highlights that wildfire has become one of the major environmental challenges facing the world under the influence of extreme climate.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"342 ","pages":"Article 120941"},"PeriodicalIF":4.2,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Extreme cooling in Northeast China in January and concurrent maximum in the lower stratospheric temperature and ozone: Case studies","authors":"Yu Shi ,&nbsp;Oleksandr Evtushevsky ,&nbsp;Gennadi Milinevsky ,&nbsp;Ruixian Yu ,&nbsp;Asen Grytsai ,&nbsp;Xiaopeng Sun ,&nbsp;Xiaolong Wang ,&nbsp;Bohdan Novosyadlyj","doi":"10.1016/j.atmosenv.2024.120938","DOIUrl":"10.1016/j.atmosenv.2024.120938","url":null,"abstract":"<div><div>This paper analyzes the four severe cooling events in Changchun, Northeast China, in January for selected years. The events in the absence of sudden stratospheric warmings were chosen. This excludes the possible effects of warm stratospheric anomalies in the polar vortex region, which may affect midlatitudes. The meridional profiles and maps for the coldest and warmest days of January are compared using the temperature and ozone data from observations and reanalysis. Based on the vertical temperature structure compared to the coldest–warmest days, the lower stratosphere–surface thermal coupling was analyzed, which has not been studied previously. It has been shown that (i) temperature increase by 5–10 °C in the lower stratosphere, (ii) lowering the tropopause by about 2–3 km, (iii) pushing the cold midtropospheric layer from climatological about 3 km to the surface with formation of the midlatitude temperature minimum, and (iv) a decrease in surface temperature in Changchun by 15–24 °C, concurrently occurred on the coldest days compared to the warmest days. Cold air in the region of the midlatitude minimum temperature, merging with the cold air of higher latitudes, contributes to the formation of the cold air outbreak pattern. The main elements of stratospheric and tropospheric dynamics (quasi-stationary and traveling planetary waves, zonally asymmetric Brewer–Dobson circulation, deformation of the tropopause and tropospheric isotherms) involved in extreme cooling events are analyzed. Because of the positive correlation between total ozone and temperature in the lower stratosphere, extremely high total ozone over the midlatitude region may serve as an indicator of warm stratospheric anomaly and possible downward thermal forcing.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"342 ","pages":"Article 120938"},"PeriodicalIF":4.2,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}