Pub Date : 2024-06-25DOI: 10.5194/acp-24-7227-2024
Zhen Liu, Massimo A. Bollasina, Laura J. Wilcox
Abstract. Reliable attribution of Asian summer monsoon variations to aerosol forcing is critical to reducing uncertainties in future projections of regional water availability, which is of utmost importance for risk management and adaptation planning in this densely populated region. Yet, simulating the monsoon remains a challenge for climate models that suffer from long-standing biases, undermining their reliability in attributing anthropogenically forced changes. We analyze a suite of climate model experiments to identify a link between model biases and monsoon responses to Asian aerosols and associated physical mechanisms, including the role of large-scale circulation changes. The aerosol impact on monsoon precipitation and circulation is strongly influenced by a model's ability to simulate the spatio-temporal variability in the climatological monsoon winds, clouds, and precipitation across Asia, which modulates the magnitude and efficacy of aerosol–cloud–precipitation interactions, an important component of the total aerosol response. There is a strong interplay between South Asia and East Asia monsoon precipitation biases and their relative predominance in driving the overall monsoon response. We found a striking contrast between the early- and late-summer aerosol-driven changes ascribable to opposite signs and seasonal evolution of the biases in the two regions. A realistic simulation of the evolution of the large-scale atmospheric circulation is crucial to realize the full extent of the aerosol impact over Asia. These findings provide important implications for better understanding and constraining the diversity and inconsistencies of model responses to aerosol changes over Asia in historical simulations and future projections.
{"title":"Impact of Asian aerosols on the summer monsoon strongly modulated by regional precipitation biases","authors":"Zhen Liu, Massimo A. Bollasina, Laura J. Wilcox","doi":"10.5194/acp-24-7227-2024","DOIUrl":"https://doi.org/10.5194/acp-24-7227-2024","url":null,"abstract":"Abstract. Reliable attribution of Asian summer monsoon variations to aerosol forcing is critical to reducing uncertainties in future projections of regional water availability, which is of utmost importance for risk management and adaptation planning in this densely populated region. Yet, simulating the monsoon remains a challenge for climate models that suffer from long-standing biases, undermining their reliability in attributing anthropogenically forced changes. We analyze a suite of climate model experiments to identify a link between model biases and monsoon responses to Asian aerosols and associated physical mechanisms, including the role of large-scale circulation changes. The aerosol impact on monsoon precipitation and circulation is strongly influenced by a model's ability to simulate the spatio-temporal variability in the climatological monsoon winds, clouds, and precipitation across Asia, which modulates the magnitude and efficacy of aerosol–cloud–precipitation interactions, an important component of the total aerosol response. There is a strong interplay between South Asia and East Asia monsoon precipitation biases and their relative predominance in driving the overall monsoon response. We found a striking contrast between the early- and late-summer aerosol-driven changes ascribable to opposite signs and seasonal evolution of the biases in the two regions. A realistic simulation of the evolution of the large-scale atmospheric circulation is crucial to realize the full extent of the aerosol impact over Asia. These findings provide important implications for better understanding and constraining the diversity and inconsistencies of model responses to aerosol changes over Asia in historical simulations and future projections.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"13 1","pages":""},"PeriodicalIF":6.3,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141452951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. Urban Green Spaces (UGS) are widely advocated for mitigating urban atmospheric environment. However, this study reveals that it can exacerbate urban ozone (O3) levels under certain conditions, as demonstrated by a September 2017 study in Guangzhou, China. Utilizing the Weather Research and Forecasting Model with the Model of Emissions of Gases and Aerosols from Nature (WRF-MEGAN) and the Community Multiscale Air Quality (CMAQ) model with a high horizontal resolution (1 km), we assessed the impact of UGS-related biogenic volatile organic compound (BVOC) emissions on urban O3. Our findings indicate that UGS-BVOC emissions in Guangzhou amounted to 666.49 Gg, primarily from isoprene (ISOP) and terpenes (TERP). These emissions contribute ~30 % of urban ISOP concentrations and their incorporations to the model significantly reduce the underestimation against observations. The study shows improvements in simulation biases for NO2, from 7.01 µg/m3 to 6.03 µg/m3, and for O3, from 7.77 µg/m3 to -1.60 µg/m3. UGS-BVOC and UGS-LUCC (land use cover changes) integration in air quality models notably enhances surface monthly mean O3 predictions by 3.6–8.0 µg/m3 (+3.8–8.5 %) and contributes up to 18.7 µg/m3 (+10.0 %) to MDA8 O3 during O3 pollution episodes. Additionally, UGS-BVOC emissions alone increase the monthly mean O3 levels by 2.2–3.0 µg/m3 (+2.3–3.2 %) in urban areas and contribute up to 6.3 µg/m3 (+3.3 %) to MDA8 O3 levels during O3 pollution episodes. These impacts can extend to surrounding suburban and rural areas through regional transport, highlighting the need for selecting low-emission vegetation and refining vegetation classification in urban planning.
{"title":"Unheralded contributions of biogenic volatile organic compounds from urban greening to ozone pollution: a high-resolution modeling study","authors":"Haofan Wang, Yuejin Li, Yiming Liu, Xiao Lu, Yang Zhang, Qi Fan, Tianhang Zhang, Chong Shen","doi":"10.5194/egusphere-2024-1163","DOIUrl":"https://doi.org/10.5194/egusphere-2024-1163","url":null,"abstract":"<strong>Abstract.</strong> Urban Green Spaces (UGS) are widely advocated for mitigating urban atmospheric environment. However, this study reveals that it can exacerbate urban ozone (O<sub>3</sub>) levels under certain conditions, as demonstrated by a September 2017 study in Guangzhou, China. Utilizing the Weather Research and Forecasting Model with the Model of Emissions of Gases and Aerosols from Nature (WRF-MEGAN) and the Community Multiscale Air Quality (CMAQ) model with a high horizontal resolution (1 km), we assessed the impact of UGS-related biogenic volatile organic compound (BVOC) emissions on urban O<sub>3</sub>. Our findings indicate that UGS-BVOC emissions in Guangzhou amounted to 666.49 Gg, primarily from isoprene (ISOP) and terpenes (TERP). These emissions contribute ~30 % of urban ISOP concentrations and their incorporations to the model significantly reduce the underestimation against observations. The study shows improvements in simulation biases for NO<sub>2</sub>, from 7.01 µg/m<sup>3</sup> to 6.03 µg/m<sup>3</sup>, and for O<sub>3</sub>, from 7.77 µg/m<sup>3</sup> to -1.60 µg/m<sup>3</sup>. UGS-BVOC and UGS-LUCC (land use cover changes) integration in air quality models notably enhances surface monthly mean O<sub>3</sub> predictions by 3.6–8.0 µg/m<sup>3 </sup>(+3.8–8.5 %) and contributes up to 18.7 µg/m<sup>3 </sup>(+10.0 %) to MDA8 O<sub>3</sub> during O<sub>3</sub> pollution episodes. Additionally, UGS-BVOC emissions alone increase the monthly mean O<sub>3</sub> levels by 2.2–3.0 µg/m<sup>3 </sup>(+2.3–3.2 %) in urban areas and contribute up to 6.3 µg/m<sup>3 </sup>(+3.3 %) to MDA8 O<sub>3</sub> levels during O<sub>3</sub> pollution episodes. These impacts can extend to surrounding suburban and rural areas through regional transport, highlighting the need for selecting low-emission vegetation and refining vegetation classification in urban planning.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"28 1","pages":""},"PeriodicalIF":6.3,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141452995","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-25DOI: 10.5194/egusphere-2024-1851
Julika Zinke, Gabriel Freitas, Rachel Ann Foster, Paul Zieger, Ernst Douglas Nilsson, Piotr Markuszewski, Matthew Edward Salter
Abstract. Primary biological aerosol particles (PBAP) can influence climate and affect human health. To investigate the aerosolization of PBAP with sea spray aerosol (SSA), we conducted ship-based campaigns in the central Baltic Sea near Östergarnsholm in May and August 2021. Using a plunging jet sea spray simulation chamber filled with local seawater, we performed controlled chamber experiments to collect filters and measure aerosols. We determined the abundance of bacteria in the chamber air and seawater by staining and fluorescence microscopy, normalizing these values to sodium concentration to calculate enrichment factors. Our results showed that bacteria were enriched in the aerosol by 13 to 488 times compared to the underlying seawater, with no significant enrichment observed in the sea surface microlayer. Bacterial abundances obtained through microscopy were compared with estimates of fluorescent PBAP (fPBAP) using a single-particle fluorescence spectrometer. We estimated bacterial emission fluxes using two independent approaches: (1) applying the enrichment factors derived from this study with mass flux estimates from previous SSA parameterizations, and (2) using a scaling approach from a companion study. Both methods produced bacterial emission flux estimates that were in good agreement and on the same order of magnitude as previous studies, while fPBAP emission flux estimates were significantly lower. Furthermore, 16S rRNA sequencing identified the diversity of bacteria enriched in the nascent SSA compared to the underlying seawater.
{"title":"Quantification and characterization of primary biological aerosol particles and bacteria aerosolized from Baltic seawater","authors":"Julika Zinke, Gabriel Freitas, Rachel Ann Foster, Paul Zieger, Ernst Douglas Nilsson, Piotr Markuszewski, Matthew Edward Salter","doi":"10.5194/egusphere-2024-1851","DOIUrl":"https://doi.org/10.5194/egusphere-2024-1851","url":null,"abstract":"<strong>Abstract.</strong> Primary biological aerosol particles (PBAP) can influence climate and affect human health. To investigate the aerosolization of PBAP with sea spray aerosol (SSA), we conducted ship-based campaigns in the central Baltic Sea near Östergarnsholm in May and August 2021. Using a plunging jet sea spray simulation chamber filled with local seawater, we performed controlled chamber experiments to collect filters and measure aerosols. We determined the abundance of bacteria in the chamber air and seawater by staining and fluorescence microscopy, normalizing these values to sodium concentration to calculate enrichment factors. Our results showed that bacteria were enriched in the aerosol by 13 to 488 times compared to the underlying seawater, with no significant enrichment observed in the sea surface microlayer. Bacterial abundances obtained through microscopy were compared with estimates of fluorescent PBAP (fPBAP) using a single-particle fluorescence spectrometer. We estimated bacterial emission fluxes using two independent approaches: (1) applying the enrichment factors derived from this study with mass flux estimates from previous SSA parameterizations, and (2) using a scaling approach from a companion study. Both methods produced bacterial emission flux estimates that were in good agreement and on the same order of magnitude as previous studies, while fPBAP emission flux estimates were significantly lower. Furthermore, 16S rRNA sequencing identified the diversity of bacteria enriched in the nascent SSA compared to the underlying seawater.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"55 1","pages":""},"PeriodicalIF":6.3,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141452996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-25DOI: 10.5194/acp-24-7253-2024
Naser Mahfouz, Johannes Mülmenstädt, Susannah Burrows
Abstract. Cloud albedo susceptibility to droplet number perturbation remains a source of uncertainty in understanding aerosol–cloud interactions and thus both past and present climate states. Through the Energy Exascale Earth System Model (E3SM) v2 experiments, we probe the effects of competing processes on cloud albedo susceptibility of low-lying marine stratocumulus in the northeast Pacific. In present-day conditions, we find that increasing precipitation suppression by aerosols increases cloud albedo susceptibility, whereas increasing cloud sedimentation decreases it. By constructing a hypothetical model configuration exhibiting negative susceptibility under all conditions, we conclude that cloud albedo change due to aerosol perturbation cannot be predicted by present-day co-variabilities in E3SM v2. As such, our null result herein challenges the assumption that present-day climate observations are sufficient to constrain past states, at least in the context of cloud albedo changes to aerosol perturbation.
{"title":"Present-day correlations are insufficient to predict cloud albedo change by anthropogenic aerosols in E3SM v2","authors":"Naser Mahfouz, Johannes Mülmenstädt, Susannah Burrows","doi":"10.5194/acp-24-7253-2024","DOIUrl":"https://doi.org/10.5194/acp-24-7253-2024","url":null,"abstract":"Abstract. Cloud albedo susceptibility to droplet number perturbation remains a source of uncertainty in understanding aerosol–cloud interactions and thus both past and present climate states. Through the Energy Exascale Earth System Model (E3SM) v2 experiments, we probe the effects of competing processes on cloud albedo susceptibility of low-lying marine stratocumulus in the northeast Pacific. In present-day conditions, we find that increasing precipitation suppression by aerosols increases cloud albedo susceptibility, whereas increasing cloud sedimentation decreases it. By constructing a hypothetical model configuration exhibiting negative susceptibility under all conditions, we conclude that cloud albedo change due to aerosol perturbation cannot be predicted by present-day co-variabilities in E3SM v2. As such, our null result herein challenges the assumption that present-day climate observations are sufficient to constrain past states, at least in the context of cloud albedo changes to aerosol perturbation.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"13 1","pages":""},"PeriodicalIF":6.3,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141453111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. Aerosol phase state is crucial for air quality, climate, and human health. Atmospheric secondary aerosols are often internally mixed with organic and inorganic components, particularly dicarboxylic acids, ammonium, sulfate, nitrate, and chloride. These complex compositions enable aqueous reaction between organic and inorganic species, significantly complicating aerosol phase behaviour during aging and making phase predictions challenging. We investigated carboxylate/ammonium salt mixtures using in-situ infrared spectroscopy. The di- and tri- carboxylates included sodium pyruvate (SP), sodium tartrate (ST), and sodium citrate (SC), while the ammonium salts included NH4NO3, NH4Cl, and (NH4)2SO4. Our results demonstrated that aqueous replacement reactions between carboxylates and ammonium salts was promoted by the formation and depletion of NH3 as relative humidity (RH) changed. Solid NaNO3, SP, and Na2SO4 formed in SP/ammonium aerosol at 35.7 %~12.7 %, 64 % and 65.5 %~60.1 % RH, respectively. In contrast, reactions between ST or SC and (NH4)2SO4 was incomplete due to the gel structure of SC or ST at low RH. Upon hydration, the deliquescence RH of Na2SO4 in SP/(NH4)2SO4 (88.8 %–95.2 %) and NaNO3 in SP/NH4NO3 (76.5–81.9 %) are higher than those of pure inorganic aerosols. Unexpectedly, aqueous Na2SO4 crystallized upon humidification in ST/(NH4)2SO4 particles at 43.6 % RH and then deliquesced with increasing RH. This is attributed to decreased viscosity and increased ion mobility, which overcome the kinetic inhibition of ion movement, leading to nucleation and growth of Na2SO4 crystal. Our findings highlight the intricate interplay between chemical components within organic/inorganic aerosol, the impact of replacement reactions on aerosol aging and phase state, and subsequently on atmospheric processes.
{"title":"The Impact of Aqueous Phase Replacement Reaction on the Phase State of Internally Mixed Organic/ammonium Aerosols","authors":"Hui Yang, Fengfeng Dong, Li Xia, Qishen Huang, Shufeng Pang, Yunhong Zhang","doi":"10.5194/egusphere-2024-1556","DOIUrl":"https://doi.org/10.5194/egusphere-2024-1556","url":null,"abstract":"<strong>Abstract.</strong> Aerosol phase state is crucial for air quality, climate, and human health. Atmospheric secondary aerosols are often internally mixed with organic and inorganic components, particularly dicarboxylic acids, ammonium, sulfate, nitrate, and chloride. These complex compositions enable aqueous reaction between organic and inorganic species, significantly complicating aerosol phase behaviour during aging and making phase predictions challenging. We investigated carboxylate/ammonium salt mixtures using in-situ infrared spectroscopy. The di- and tri- carboxylates included sodium pyruvate (SP), sodium tartrate (ST), and sodium citrate (SC), while the ammonium salts included NH<sub>4</sub>NO<sub>3</sub>, NH<sub>4</sub>Cl, and (NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub>. Our results demonstrated that aqueous replacement reactions between carboxylates and ammonium salts was promoted by the formation and depletion of NH<sub>3</sub> as relative humidity (RH) changed. Solid NaNO<sub>3</sub>, SP, and Na<sub>2</sub>SO<sub>4</sub> formed in SP/ammonium aerosol at 35.7 %~12.7 %, 64 % and 65.5 %~60.1 % RH, respectively. In contrast, reactions between ST or SC and (NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub> was incomplete due to the gel structure of SC or ST at low RH. Upon hydration, the deliquescence RH of Na<sub>2</sub>SO<sub>4</sub> in SP/(NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub> (88.8 %–95.2 %) and NaNO<sub>3</sub> in SP/NH<sub>4</sub>NO<sub>3</sub> (76.5–81.9 %) are higher than those of pure inorganic aerosols. Unexpectedly, aqueous Na<sub>2</sub>SO<sub>4</sub> crystallized upon humidification in ST/(NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub> particles at 43.6 % RH and then deliquesced with increasing RH. This is attributed to decreased viscosity and increased ion mobility, which overcome the kinetic inhibition of ion movement, leading to nucleation and growth of Na<sub>2</sub>SO<sub>4</sub> crystal. Our findings highlight the intricate interplay between chemical components within organic/inorganic aerosol, the impact of replacement reactions on aerosol aging and phase state, and subsequently on atmospheric processes.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"44 1","pages":""},"PeriodicalIF":6.3,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141444759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-24DOI: 10.5194/acp-24-7179-2024
Britta Schäfer, Robert Oscar David, Paraskevi Georgakaki, Julie Thérèse Pasquier, Georgia Sotiropoulou, Trude Storelvmo
Abstract. The representation of Arctic clouds and their phase distributions, i.e., the amount of ice and supercooled water, influences predictions of future Arctic warming. Therefore, it is essential that cloud phase is correctly captured by models in order to accurately predict the future Arctic climate. Ice crystal formation in clouds happens through ice nucleation (primary ice production) and ice multiplication (secondary ice production). In common weather and climate models, rime splintering is the only secondary ice production process included. In addition, prescribed number concentrations of cloud condensation nuclei or cloud droplets and ice-nucleating particles are often overestimated in Arctic environments by standard model configurations. This can lead to a misrepresentation of the phase distribution and precipitation formation in Arctic mixed-phase clouds, with important implications for the Arctic surface energy budget. During the Ny-Ålesund Aerosol Cloud Experiment (NASCENT), a holographic probe mounted on a tethered balloon took in situ measurements of number and mass concentrations of ice crystals and cloud droplets in Svalbard, Norway, during fall 2019 and spring 2020. In this study, we choose one case study from this campaign that shows evidence of strong secondary ice production and use the Weather Research and Forecasting (WRF) model to simulate it at a high vertical and spatial resolution. We test the performance of different microphysical parametrizations and apply a new state-of-the-art secondary ice parametrization. We find that agreement with observations highly depends on the prescribed cloud condensation nuclei/cloud droplet and ice-nucleating particle concentrations and requires an enhancement of secondary ice production processes. Lowering mass mixing ratio thresholds for rime splintering inside the Morrison microphysics scheme is crucial to enable secondary ice production and thereby match observations for the right reasons. In our case, rime splintering is required to initiate collisional breakup. The simulated contribution from collisional breakup is larger than that from droplet shattering. Simulating ice production correctly for the right reasons is a prerequisite for reliable simulations of Arctic mixed-phase cloud responses to future temperature or aerosol perturbations.
{"title":"Simulations of primary and secondary ice production during an Arctic mixed-phase cloud case from the Ny-Ålesund Aerosol Cloud Experiment (NASCENT) campaign","authors":"Britta Schäfer, Robert Oscar David, Paraskevi Georgakaki, Julie Thérèse Pasquier, Georgia Sotiropoulou, Trude Storelvmo","doi":"10.5194/acp-24-7179-2024","DOIUrl":"https://doi.org/10.5194/acp-24-7179-2024","url":null,"abstract":"Abstract. The representation of Arctic clouds and their phase distributions, i.e., the amount of ice and supercooled water, influences predictions of future Arctic warming. Therefore, it is essential that cloud phase is correctly captured by models in order to accurately predict the future Arctic climate. Ice crystal formation in clouds happens through ice nucleation (primary ice production) and ice multiplication (secondary ice production). In common weather and climate models, rime splintering is the only secondary ice production process included. In addition, prescribed number concentrations of cloud condensation nuclei or cloud droplets and ice-nucleating particles are often overestimated in Arctic environments by standard model configurations. This can lead to a misrepresentation of the phase distribution and precipitation formation in Arctic mixed-phase clouds, with important implications for the Arctic surface energy budget. During the Ny-Ålesund Aerosol Cloud Experiment (NASCENT), a holographic probe mounted on a tethered balloon took in situ measurements of number and mass concentrations of ice crystals and cloud droplets in Svalbard, Norway, during fall 2019 and spring 2020. In this study, we choose one case study from this campaign that shows evidence of strong secondary ice production and use the Weather Research and Forecasting (WRF) model to simulate it at a high vertical and spatial resolution. We test the performance of different microphysical parametrizations and apply a new state-of-the-art secondary ice parametrization. We find that agreement with observations highly depends on the prescribed cloud condensation nuclei/cloud droplet and ice-nucleating particle concentrations and requires an enhancement of secondary ice production processes. Lowering mass mixing ratio thresholds for rime splintering inside the Morrison microphysics scheme is crucial to enable secondary ice production and thereby match observations for the right reasons. In our case, rime splintering is required to initiate collisional breakup. The simulated contribution from collisional breakup is larger than that from droplet shattering. Simulating ice production correctly for the right reasons is a prerequisite for reliable simulations of Arctic mixed-phase cloud responses to future temperature or aerosol perturbations.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"26 1","pages":""},"PeriodicalIF":6.3,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141444767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-24DOI: 10.5194/acp-24-7203-2024
Moritz Günther, Hauke Schmidt, Claudia Timmreck, Matthew Toohey
Abstract. Previous research has shown that stratospheric aerosol causes only a small temperature change per unit forcing because they produce stronger cooling in the tropical Indian Ocean and the western Pacific Ocean than in the global mean. The enhanced temperature change in this so-called “warm-pool” region activates strongly negative local and remote feedbacks, which dampen the global mean temperature response. This paper addresses the question of why stratospheric aerosol forcing affects warm-pool temperatures more strongly than CO2 forcing, using idealized MPI-ESM simulations. We show that the aerosol's enhanced effective forcing at the top of the atmosphere (TOA) over the warm pool contributes to the warm-pool-intensified temperature change but is not sufficient to explain the effect. Instead, the pattern of surface effective forcing, which is substantially different from the effective forcing at the TOA, is more closely linked to the temperature pattern. Independent of surface temperature changes, the aerosol heats the tropical stratosphere, accelerating the Brewer–Dobson circulation. The intensified Brewer–Dobson circulation exports additional energy from the tropics to the extratropics, which leads to a particularly strong negative forcing at the tropical surface. These results show how forced circulation changes can affect the climate response by altering the surface forcing pattern. Furthermore, they indicate that the established approach of diagnosing effective forcing at the TOA is useful for global means, but a surface perspective on the forcing must be adopted to understand the evolution of temperature patterns.
摘要以往的研究表明，平流层气溶胶每单位强迫只引起很小的温度变化，因为它们在热带印度洋和西太平洋产生的降温比在全球平均温度产生的降温更强。在这个所谓的 "暖池 "区域，温度变化的增强激活了强烈的本地和远程负反馈，从而抑制了全球平均温度响应。本文利用理想化的 MPI-ESM 模拟，探讨了为什么平流层气溶胶强迫对暖池温度的影响比二氧化碳强迫更强。我们的研究表明，气溶胶在暖池上空大气顶部（TOA）增强的有效作用力是暖池温度变化加剧的原因之一，但不足以解释这种效应。相反，地表有效作用力的模式与 TOA 上的有效作用力有很大不同，与温度模式的关系更为密切。与地表温度变化无关，气溶胶会加热热带平流层，加速布鲁尔-多布森环流。增强的布鲁尔-多布森环流将额外的能量从热带地区输出到外热带地区，从而在热带地表产生特别强的负强迫。这些结果表明了强迫环流变化如何通过改变地表强迫模式来影响气候响应。此外，这些结果还表明，诊断 TOA 有效强迫的既定方法对全球手段是有用的，但必须从表面强迫的角度来理解温度模式的演变。
{"title":"Why does stratospheric aerosol forcing strongly cool the warm pool?","authors":"Moritz Günther, Hauke Schmidt, Claudia Timmreck, Matthew Toohey","doi":"10.5194/acp-24-7203-2024","DOIUrl":"https://doi.org/10.5194/acp-24-7203-2024","url":null,"abstract":"Abstract. Previous research has shown that stratospheric aerosol causes only a small temperature change per unit forcing because they produce stronger cooling in the tropical Indian Ocean and the western Pacific Ocean than in the global mean. The enhanced temperature change in this so-called “warm-pool” region activates strongly negative local and remote feedbacks, which dampen the global mean temperature response. This paper addresses the question of why stratospheric aerosol forcing affects warm-pool temperatures more strongly than CO2 forcing, using idealized MPI-ESM simulations. We show that the aerosol's enhanced effective forcing at the top of the atmosphere (TOA) over the warm pool contributes to the warm-pool-intensified temperature change but is not sufficient to explain the effect. Instead, the pattern of surface effective forcing, which is substantially different from the effective forcing at the TOA, is more closely linked to the temperature pattern. Independent of surface temperature changes, the aerosol heats the tropical stratosphere, accelerating the Brewer–Dobson circulation. The intensified Brewer–Dobson circulation exports additional energy from the tropics to the extratropics, which leads to a particularly strong negative forcing at the tropical surface. These results show how forced circulation changes can affect the climate response by altering the surface forcing pattern. Furthermore, they indicate that the established approach of diagnosing effective forcing at the TOA is useful for global means, but a surface perspective on the forcing must be adopted to understand the evolution of temperature patterns.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"20 1","pages":""},"PeriodicalIF":6.3,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141444762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-24DOI: 10.5194/egusphere-2024-1488
Haifeng Yu, Yunhua Chang, Lin Cheng, Yusen Duan, Jianlin Hu
Abstract. A growing body of research has demonstrated the effectiveness of China’s Air Pollution Prevention and Control Action Plan in controlling PM2.5 pollution. However, there is a lack of long-term studies investigating the impact of these abatement policies on carbonaceous aerosols in PM2.5, particularly secondary organic carbon (SOC). Shanghai, as China’s largest megacity and prominent industrial hub, serves as a crucial gateway to the nation’s rapid development with a population exceeding twenty million. In this study, we conducted hourly online measurements of organic carbon (OC) and elemental carbon (EC) in PM2.5 in Shanghai from July 2010 to July 2017. The results revealed that the annual concentrations (mean ± 1 σ) of OC and EC reached their peaks in 2013 (9.5 ± 6.4 and 2.7 ± 2.6 µg m-3 to 3.0 ± 2.3 µg m-3 and 2.7 ± 2.1 µg m-3). Subsequently, a consistent year-by-year decrease in both OC and EC concentrations was observed, mirroring the trend observed for PM2.5. Primary organic carbon (POC), the primary component of OC, accounted for an average of 65.6 %, displaying similar trends to OC. This finding indicates the effectiveness of primary emission control measures. However, the concentration of secondary organic carbon (SOC) did not decrease from 2013 to 2017, remaining relatively stable within the range of 2.7 ± 2.6 µg m-3 to 3.0 ± 2.3 µg m-3. When considering data from previous studies in Shanghai, concentrations of SOC did not exhibit a noticeable decline until 2018, coinciding with the implementation of measures targeting volatile organic compounds (VOCs) emissions. Seasonally, with the exception of 2011, OC and EC concentrations were highest during winter, likely influenced by unfavourable meteorological conditions and long-range transport. SOC displayed no distinct seasonal fluctuations, as its formation is influenced by both photochemical reactions and meteorological conditions. POC and SOC exhibited different diurnal patterns, but neither showed a significant weekend effect, suggesting limited reduction in anthropogenic activities during weekends. Furthermore, SOC concentrations exhibited simultaneous increases in summer, particularly when O3 concentrations exceeded 50 µg m-3, indicating that stronger oxidation reactions contribute to higher SOC concentrations. Our findings also revealed concentration gradients of SOC dependent on wind direction (WD) and wind speed (WS), with higher concentrations typically observed for winds originating from the southwest and northwest. Potential sources from distant regions were analyzed using the potential source contribution function (PSCF), indicating that the geographical potential source area is concentrated near the middle and lower Yangtze River.
{"title":"Measurement Report: Long-term Assessment of Primary and Secondary Organic Aerosols in Shanghai Megacity throughout China’s Clean Air Actions since 2010","authors":"Haifeng Yu, Yunhua Chang, Lin Cheng, Yusen Duan, Jianlin Hu","doi":"10.5194/egusphere-2024-1488","DOIUrl":"https://doi.org/10.5194/egusphere-2024-1488","url":null,"abstract":"<strong>Abstract.</strong> A growing body of research has demonstrated the effectiveness of China’s Air Pollution Prevention and Control Action Plan in controlling PM<sub>2.5</sub> pollution. However, there is a lack of long-term studies investigating the impact of these abatement policies on carbonaceous aerosols in PM<sub>2.5</sub>, particularly secondary organic carbon (SOC). Shanghai, as China’s largest megacity and prominent industrial hub, serves as a crucial gateway to the nation’s rapid development with a population exceeding twenty million. In this study, we conducted hourly online measurements of organic carbon (OC) and elemental carbon (EC) in PM<sub>2.5</sub> in Shanghai from July 2010 to July 2017. The results revealed that the annual concentrations (mean ± 1 σ) of OC and EC reached their peaks in 2013 (9.5 ± 6.4 and 2.7 ± 2.6 µg m<sup>-3</sup> to 3.0 ± 2.3 µg m<sup>-3</sup> and 2.7 ± 2.1 µg m<sup>-3</sup>). Subsequently, a consistent year-by-year decrease in both OC and EC concentrations was observed, mirroring the trend observed for PM<sub>2.5</sub>. Primary organic carbon (POC), the primary component of OC, accounted for an average of 65.6 %, displaying similar trends to OC. This finding indicates the effectiveness of primary emission control measures. However, the concentration of secondary organic carbon (SOC) did not decrease from 2013 to 2017, remaining relatively stable within the range of 2.7 ± 2.6 µg m<sup>-3</sup> to 3.0 ± 2.3 µg m<sup>-3</sup>. When considering data from previous studies in Shanghai, concentrations of SOC did not exhibit a noticeable decline until 2018, coinciding with the implementation of measures targeting volatile organic compounds (VOCs) emissions. Seasonally, with the exception of 2011, OC and EC concentrations were highest during winter, likely influenced by unfavourable meteorological conditions and long-range transport. SOC displayed no distinct seasonal fluctuations, as its formation is influenced by both photochemical reactions and meteorological conditions. POC and SOC exhibited different diurnal patterns, but neither showed a significant weekend effect, suggesting limited reduction in anthropogenic activities during weekends. Furthermore, SOC concentrations exhibited simultaneous increases in summer, particularly when O<sub>3</sub> concentrations exceeded 50 µg m<sup>-3</sup>, indicating that stronger oxidation reactions contribute to higher SOC concentrations. Our findings also revealed concentration gradients of SOC dependent on wind direction (WD) and wind speed (WS), with higher concentrations typically observed for winds originating from the southwest and northwest. Potential sources from distant regions were analyzed using the potential source contribution function (PSCF), indicating that the geographical potential source area is concentrated near the middle and lower Yangtze River.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"20 1","pages":""},"PeriodicalIF":6.3,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141444764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-24DOI: 10.5194/egusphere-2024-1784
Fan Lu, Kai Qin, Jason Blake Cohen, Qin He, Pravash Tiwari, Wei Hu, Chang Ye, Yanan Shan, Qing Xu, Shuo Wang, Qiansi Tu
Abstract. This work focuses on Changzhi, Shanxi China, a city and surrounding rural region with one of the highest atmospheric concentrations of methane (CH4) world-wide (campaign-wide minimum/mean/standard deviation/max observations: 2.0, 2.9, 1.3, and 16 ppm) due to a rapid increase in the mining, production, and use of coal over the past decade. An intensive 15-day surface observation campaign of CH4 is used to drive a new analytical, mass-conserving method to compute and attribute CH4 emissions. Observations made in concentric circles at 1 km, 3 km, and 5 km around a high production high gas coal mine yielded emissions of 0.73, 0.28, and 0.15 ppm min-1 respectively. Attribution used a 2-box mass conserving model to identify the known mine’s emissions from 0.042–5.3 ppm min-1, and a previously unidentified mine’s emission from 0.22–7.9 ppm min-1. These results demonstrate the importance of simultaneously quantifying both the spatial and temporal distribution of CH4 to better control regional-scale CH4 emissions. Results of the attribution are used in tandem with observations of boundary layer height to quantify policy-relevant emissions from the two coal mines as 13670±7400 kg h-1 and 5070±2270 kg h-1 respectively. Both mines display a fat tail distribution, with respective 25th, median, and 75th percentile values of [870, 7500, 38700] kg h-1 and [431, 1590, 7000] kg h-1. These findings are demonstrated to be higher than CH4 emissions from equivalent oil and gas operations in the USA, with one about double and the other similar to day-to-day emissions inverted over 5-years using TROPOMI over the same region.
{"title":"Surface Observation Constrained High Frequency Coal Mine Methane Emissions in Shanxi China Reveal More Emissions than Inventories, Consistency with Satellite Inversion","authors":"Fan Lu, Kai Qin, Jason Blake Cohen, Qin He, Pravash Tiwari, Wei Hu, Chang Ye, Yanan Shan, Qing Xu, Shuo Wang, Qiansi Tu","doi":"10.5194/egusphere-2024-1784","DOIUrl":"https://doi.org/10.5194/egusphere-2024-1784","url":null,"abstract":"<strong>Abstract.</strong> This work focuses on Changzhi, Shanxi China, a city and surrounding rural region with one of the highest atmospheric concentrations of methane (CH<sub>4</sub>) world-wide (campaign-wide minimum/mean/standard deviation/max observations: 2.0, 2.9, 1.3, and 16 ppm) due to a rapid increase in the mining, production, and use of coal over the past decade. An intensive 15-day surface observation campaign of CH<sub>4</sub> is used to drive a new analytical, mass-conserving method to compute and attribute CH<sub>4</sub> emissions. Observations made in concentric circles at 1 km, 3 km, and 5 km around a high production high gas coal mine yielded emissions of 0.73, 0.28, and 0.15 ppm min<sup>-1</sup> respectively. Attribution used a 2-box mass conserving model to identify the known mine’s emissions from 0.042–5.3 ppm min<sup>-1</sup>, and a previously unidentified mine’s emission from 0.22–7.9 ppm min<sup>-1</sup>. These results demonstrate the importance of simultaneously quantifying both the spatial and temporal distribution of CH<sub>4</sub> to better control regional-scale CH<sub>4</sub> emissions. Results of the attribution are used in tandem with observations of boundary layer height to quantify policy-relevant emissions from the two coal mines as 13670±7400 kg h<sup>-1</sup> and 5070±2270 kg h<sup>-1 </sup>respectively. Both mines display a fat tail distribution, with respective 25<sup>th</sup>, median, and 75<sup>th</sup> percentile values of [870, 7500, 38700] kg h<sup>-1</sup> and [431, 1590, 7000] kg h<sup>-1</sup>. These findings are demonstrated to be higher than CH<sub>4</sub> emissions from equivalent oil and gas operations in the USA, with one about double and the other similar to day-to-day emissions inverted over 5-years using TROPOMI over the same region.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"24 1","pages":""},"PeriodicalIF":6.3,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141444753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-24DOI: 10.5194/egusphere-2024-1717
Zilu Zhang, Libo Zhou, Meigen Zhang
<strong>Abstract.</strong> The rapid warming of the Arctic, accompanied by glacier and sea ice melt, has significant consequences for the Earth's climate, ecosystems, and economy. Recent evidence suggests that the snow-darkening effect (SDE) induced by light-absorbing particles, such as black carbon (BC) deposition, could greatly influence rapid warming in the Arctic. However, there is still a lack of ensemble simulations using high-resolution models for investigating the impacts of the SDE resulting from BC deposition on the Arctic surface energy balance. By integrating the physically based Snow, Ice, Aerosol, and Radiation (SNICAR) model with a polar-optimized version of the Weather Research and Forecasting model (Polar-WRF), this study aimed to quantify the impacts of the SDE due to BC deposition and analyze the relationship between BC aerosol mass in snow (represented by snow depth) and snow albedo reduction. The simulation results indicate that BC deposition can directly affect the surface energy balance by decreasing snow albedo and its corresponding radiative forcing (RF). On average, BC deposition at 50 ng g<sup>-1</sup> causes a radiative forcing (RF) of 1.6 W m<sup>-2</sup> in off-line simulations (without surface feedbacks) and 1.4 W m<sup>-2</sup> in on-line simulations (with surface feedbacks). The high RF caused by BC deposition reached 1–4 W m<sup>-2</sup> and mainly occurred in Greenland, Baffin Island and East Siberia, where areas with deep snow depths and large snow densities are prevalent. The changes in snow albedo are indeed strongly linked to the mass of BC aerosols. Notably, a clear linear relationship was established between snow depth and the reduction in snow albedo, with a correlation coefficient exceeding 0.9 and an R-squared value greater than 0.85 when the snow depth is shallow. However, as snow depth increases, the impact of BC on snow albedo gradually diminishes until it reaches its maximum value when the snowpack becomes sufficiently optically thick. Regions with deep snowpack, such as Greenland, tend to exhibit greater sensitivity to BC deposition due to the higher absolute mass of BC and the longer duration of the SDE. For a given column-mean BC concentration in snow, the impacts of the SDE are approximately 25–41 % greater in deep snow-covered areas than in shallow snow-covered areas, leading to a 19–40 % increase in snowmelt. A comparison between off-line and on-line coupled simulations using Polar-WRF/Noah-MP and SNICAR has provided valuable insights into the critical mechanisms and key factors influencing changes in surface heat transfer due to the impacts of the SDE induced by BC deposition in the Arctic. It has been observed that various processes, such as snow melting and land‒atmosphere interactions, play significant roles in assessing changes in the surface energy balance caused by BC deposition. Notably, off-line simulations tend to overestimate the impacts of the SDE, sometimes by more than 50 %, due
摘要伴随着冰川和海冰融化，北极地区迅速变暖，对地球气候、生态系统和经济产生了重大影响。最近的证据表明，黑碳（BC）沉积等光吸收颗粒引起的雪变暗效应（SDE）可能会对北极地区的快速变暖产生重大影响。然而，目前仍缺乏利用高分辨率模型进行的集合模拟，来研究黑碳沉积导致的黑化效应对北极地表能量平衡的影响。本研究通过将基于物理的雪、冰、气溶胶和辐射（SNICAR）模型与极地优化版天气研究和预报模型（Polar-WRF）进行集成，旨在量化 BC 沉积导致的 SDE 的影响，并分析雪中 BC 气溶胶质量（以雪深表示）与雪反照率降低之间的关系。模拟结果表明，BC 沉积可通过降低雪反照率及其相应的辐射强迫（RF）直接影响地表能量平衡。平均而言，在离线模拟（无地表反馈）和在线模拟（有地表反馈）中，50 ng g-1 的 BC 沉积造成的辐射强迫（RF）分别为 1.6 W m-2 和 1.4 W m-2。由 BC 沉积引起的高 RF 达到 1-4 W m-2，主要发生在格陵兰岛、巴芬岛和东西伯利亚，这些地区普遍积雪深且雪密度大。雪地反照率的变化确实与 BC 气溶胶的质量密切相关。值得注意的是，积雪深度与雪反照率的降低之间存在明显的线性关系，当积雪深度较浅时，相关系数超过 0.9，R 平方值大于 0.85。然而，随着积雪深度的增加，BC 对雪反照率的影响逐渐减小，直到积雪厚度达到足够的光学厚度时才达到最大值。格陵兰岛等积雪较深的地区，由于 BC 的绝对质量较大，SDE 的持续时间较长，往往对 BC 沉积表现出更大的敏感性。对于给定的雪中 BC 柱均值浓度，SDE 对积雪较深地区的影响比积雪较浅地区大约 25-41%，导致融雪量增加 19-40%。利用极地-WRF/Noah-MP 和 SNICAR 进行的离线和在线耦合模拟比较，为了解北极 BC 沉积引起的 SDE 对地表传热变化的关键机制和主要影响因素提供了宝贵的见解。据观察，雪融化和陆地-大气相互作用等各种过程在评估 BC 沉积引起的地表能量平衡变化方面发挥了重要作用。值得注意的是，由于缺乏相关过程，离线模拟往往会高估 SDE 的影响，有时高估超过 50%。这项研究强调了积雪条件和陆地-大气相互作用对评估 BC 沉积造成的 SDE 影响的重要性。因此，有必要将包含详细物理过程的高分辨率建模研究列为优先事项，以提高我们对SDE对北极气候变化影响的认识。
{"title":"Modeling study of the snow darkening effect by black carbon deposition over the Arctic during the melting period","authors":"Zilu Zhang, Libo Zhou, Meigen Zhang","doi":"10.5194/egusphere-2024-1717","DOIUrl":"https://doi.org/10.5194/egusphere-2024-1717","url":null,"abstract":"<strong>Abstract.</strong> The rapid warming of the Arctic, accompanied by glacier and sea ice melt, has significant consequences for the Earth's climate, ecosystems, and economy. Recent evidence suggests that the snow-darkening effect (SDE) induced by light-absorbing particles, such as black carbon (BC) deposition, could greatly influence rapid warming in the Arctic. However, there is still a lack of ensemble simulations using high-resolution models for investigating the impacts of the SDE resulting from BC deposition on the Arctic surface energy balance. By integrating the physically based Snow, Ice, Aerosol, and Radiation (SNICAR) model with a polar-optimized version of the Weather Research and Forecasting model (Polar-WRF), this study aimed to quantify the impacts of the SDE due to BC deposition and analyze the relationship between BC aerosol mass in snow (represented by snow depth) and snow albedo reduction. The simulation results indicate that BC deposition can directly affect the surface energy balance by decreasing snow albedo and its corresponding radiative forcing (RF). On average, BC deposition at 50 ng g<sup>-1</sup> causes a radiative forcing (RF) of 1.6 W m<sup>-2</sup> in off-line simulations (without surface feedbacks) and 1.4 W m<sup>-2</sup> in on-line simulations (with surface feedbacks). The high RF caused by BC deposition reached 1–4 W m<sup>-2</sup> and mainly occurred in Greenland, Baffin Island and East Siberia, where areas with deep snow depths and large snow densities are prevalent. The changes in snow albedo are indeed strongly linked to the mass of BC aerosols. Notably, a clear linear relationship was established between snow depth and the reduction in snow albedo, with a correlation coefficient exceeding 0.9 and an R-squared value greater than 0.85 when the snow depth is shallow. However, as snow depth increases, the impact of BC on snow albedo gradually diminishes until it reaches its maximum value when the snowpack becomes sufficiently optically thick. Regions with deep snowpack, such as Greenland, tend to exhibit greater sensitivity to BC deposition due to the higher absolute mass of BC and the longer duration of the SDE. For a given column-mean BC concentration in snow, the impacts of the SDE are approximately 25–41 % greater in deep snow-covered areas than in shallow snow-covered areas, leading to a 19–40 % increase in snowmelt. A comparison between off-line and on-line coupled simulations using Polar-WRF/Noah-MP and SNICAR has provided valuable insights into the critical mechanisms and key factors influencing changes in surface heat transfer due to the impacts of the SDE induced by BC deposition in the Arctic. It has been observed that various processes, such as snow melting and land‒atmosphere interactions, play significant roles in assessing changes in the surface energy balance caused by BC deposition. Notably, off-line simulations tend to overestimate the impacts of the SDE, sometimes by more than 50 %, due ","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"53 1","pages":""},"PeriodicalIF":6.3,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141444768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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