Atmospheric Chemistry and Physics最新文献_第7页

Cloud-type-dependent mixed-phase cloud climatology from CloudSat/CALIPSO measurements 来自CloudSat/CALIPSO测量的云类型相关的混合相云气候学

IF 6.3 1区地球科学

Atmospheric Chemistry and Physics Pub Date : 2026-09-22 DOI: 10.5194/acp-26-13319-2026

Kang Yang,Zhien Wang,Min Deng

{"title":"Cloud-type-dependent mixed-phase cloud climatology from CloudSat/CALIPSO measurements","authors":"Kang Yang,Zhien Wang,Min Deng","doi":"10.5194/acp-26-13319-2026","DOIUrl":"https://doi.org/10.5194/acp-26-13319-2026","url":null,"abstract":"Mixed-phase clouds play a critical role in Earth's radiation budget but remain a major source of uncertainty in climate models. Existing satellite climatologies mostly describe mixed-phase clouds in aggregate, without separating cloud types that differ in dynamics, vertical structure, spatial distribution, and macrophysical properties. Here we use CloudSat/CALIPSO observations to develop a global, cloud-type-dependent climatology of mixed-phase cloud and examine its spatial, vertical, seasonal, and regional variations. Identified mixed-phase clouds have a global mean occurrence of 18.5 %. Stratus plus stratocumulus (St+Sc) dominates high-latitude mixed-phase occurrence, with local values exceeding 40 % over the Southern Ocean and the Greenland-Iceland-Norwegian seas, whereas altocumulus (Ac) and nimbostratus plus deep convection (Ns+DC) contribute most strongly in midlatitude storm-track regions and convectively active tropical regions. At a given cloud-top temperature, the dominant cloud phase differs substantially among cloud types and regions, indicating that cloud-top temperature alone does not uniquely determine cloud thermodynamic phase. Seasonal and surface contrasts are especially strong for St+Sc: in the NH 45–75° N band, monthly mean occurrence over open ocean increases from about 2 %–6 % in summer to 24 %–25 % in winter, whereas in the SH 45–75° S band St+Sc over open ocean reaches its annual minimum in austral summer but over sea ice reaches its minimum in austral winter. These results demonstrate the importance of cloud type for characterizing mixed-phase cloud climatology and provide observational constraints for evaluating the representation of mixed-phase clouds in climate models.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"64 1 1","pages":"13319-13339"},"PeriodicalIF":6.3,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149021836","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}

引用次数: 0

Apportioning light absorption of ambient aerosols to black carbon, brown carbon, and lensing effect using a PAX-ISS hybrid method: insights into absorption enhancement 利用PAX-ISS混合方法将环境气溶胶的光吸收分配给黑碳、棕色碳和透镜效应：对吸收增强的见解

IF 6.3 1区地球科学

Atmospheric Chemistry and Physics Pub Date : 2026-09-22 DOI: 10.5194/acp-26-13303-2026

Yi Shen,Guorui Zhi,Wenjing Jin,Yao Kong,Yuzhe Zhang,Zhengying Li,Jianzhong Sun,Yuankai Wang,Zhijian Liang

{"title":"Apportioning light absorption of ambient aerosols to black carbon, brown carbon, and lensing effect using a PAX-ISS hybrid method: insights into absorption enhancement","authors":"Yi Shen,Guorui Zhi,Wenjing Jin,Yao Kong,Yuzhe Zhang,Zhengying Li,Jianzhong Sun,Yuankai Wang,Zhijian Liang","doi":"10.5194/acp-26-13303-2026","DOIUrl":"https://doi.org/10.5194/acp-26-13303-2026","url":null,"abstract":"Accurately apportioning aerosol light absorption to black carbon (BC), brown carbon (BrC), and the lensing effect is crucial for constraining aerosol radiative forcing, yet existing methods often fail to resolve all three components simultaneously. Here, we introduce and demonstrate an integrated measurement framework that couples photoacoustic spectroscopy (PAX) with an integrating sphere system using solvent mediation (ISS). This PAX-ISS hybrid method quantifies the total absorption of ambient aerosols ( B abs_coated ) and removes the lensing effect via solvent-mediated lensing-free optical state to obtain the uncoated absorption ( B abs_uncoated ). The absorption solely due to the lensing effect ( B abs,lensing ) is then directly quantified as their difference: Babs,lensing=Babs_coated-Babs_uncoated. B abs_uncoated is further spectrally decomposed into BC and BrC contributions ( B abs,BC and B abs,BrC ) using a dual-wavelength iterative algorithm. Applied to seasonal samples in Beijing during 2023, the method revealed that BC dominated light absorption, with BrC contributing approximately 10 % annually. The apparent lensing-induced enhancement averaged 40 % of total absorption but exhibited strong seasonal (4.6 %–52.0 %) and spectral variations, contracting sharply at shorter wavelengths – a pattern suggestive of a BrC “blocking effect” that may offset lensing enhancement. Our field measurements provide observational indications consistent with this blocking effect, which was previously proposed by other researchers based on numerical simulations. The annual wavelength-averaged absorption enhancement factor ( E abs ) was 1.69 ± 0.10. This methodology provides a robust, observationally constrained approach to apportion aerosol absorption, offering refined insights for climate modeling.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"36 1","pages":"13303-13318"},"PeriodicalIF":6.3,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149021837","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}

引用次数: 0

An underappreciated cyclonic-like circulation affects high summer ozone in North China Plain 一个未被充分认识的类气旋环流影响华北平原夏季高臭氧

IF 6.3 1区地球科学

Atmospheric Chemistry and Physics Pub Date : 2026-09-22 DOI: 10.5194/acp-26-13253-2026

Wenhao Qiao,Xipeng Jin,Xi Chen,Ziyu Long,Zhenjiang Yang,Lei Chen,Ke Li,Hong Liao

{"title":"An underappreciated cyclonic-like circulation affects high summer ozone in North China Plain","authors":"Wenhao Qiao,Xipeng Jin,Xi Chen,Ziyu Long,Zhenjiang Yang,Lei Chen,Ke Li,Hong Liao","doi":"10.5194/acp-26-13253-2026","DOIUrl":"https://doi.org/10.5194/acp-26-13253-2026","url":null,"abstract":"China continues to experience severe ozone pollution, particularly over the North China Plain (NCP) during summer. Ozone pollution is generally considered to be associated with anticyclonic circulation. However, this study reveals that a previously underappreciated cyclonic-like circulation also plays a substantial role in ozone pollution over the NCP. Based on a systematic analysis of summertime observations from 2017 to 2022, we identify 209 ozone pollution days, 60 of which are associated with cyclonic-like circulation. Under cyclonic-like circulation, northwesterly winds prevail over the NCP. As the airflow crosses the Taihang Mountains, it undergoes adiabatic descent and induce foehn winds, leading to anomalous warming (+1.78 °C) and drying (−15 %) in the western NCP. Foehn-induced warming substantially enhances ozone photochemical production, resulting in severe ozone pollution over the western NCP, with MDA8 ozone concentrations exceeding 102.2 ppb. In addition, subsiding airflow transports ozone-rich air from the residual layer downward, leading to elevated nighttime ozone along the leeward foothills. Consequently, the impact of cyclonic-like circulation on ozone pollution exhibits pronounced spatial heterogeneity, with stronger ozone enhancement over the western than the central and eastern NCP, in contrast to the relatively uniform ozone increase over the NCP under anticyclonic circulation. More importantly, the frequency of cyclonic-like circulation exhibits an increasing trend during 1980–2024, suggesting its growing importance in modulating ozone pollution. We further demonstrate that emission control strategies should be tailored to different circulations. Under cyclonic-like circulation, local emission reductions within the NCP are most effective, whereas under anticyclonic circulation, reductions in the adjacent southeastern region yield greater mitigation benefits.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"269 1","pages":"13253-13265"},"PeriodicalIF":6.3,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149021873","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}

引用次数: 0

Urban surface-atmosphere fluxes of selected pptv-level oxygenated organic molecules (OOMs) from eddy covariance observations 涡旋相关观测中选定pptv水平含氧有机分子（OOMs）的城市地表大气通量

IF 6.3 1区地球科学

Atmospheric Chemistry and Physics Pub Date : 2026-09-21 DOI: 10.5194/acp-26-13213-2026

Jieya Sun,Xinyu Wang,Jingya Hua,Bo Zhu,Nan Chen,Huan Yu

{"title":"Urban surface-atmosphere fluxes of selected pptv-level oxygenated organic molecules (OOMs) from eddy covariance observations","authors":"Jieya Sun,Xinyu Wang,Jingya Hua,Bo Zhu,Nan Chen,Huan Yu","doi":"10.5194/acp-26-13213-2026","DOIUrl":"https://doi.org/10.5194/acp-26-13213-2026","url":null,"abstract":"Oxygenated Organic Molecules (OOMs) represent a substantial fraction of ambient reactive carbon and are potential precursors of secondary organic aerosols (SOA). Surface-atmosphere exchange flux modulates OOM budgets and subsequent SOA formation. This study presents the first urban eddy covariance measurements of pptv-level OOM surface-atmosphere fluxes, using an iodide-adduct chemical ionization mass spectrometer during the hottest month of the year in a central China megacity. We addressed the challenges of retrieving reliable fluxes for OOM species with low concentration signal-to-noise-ratios. Effects of mass spectral integration time and water vapor variation on flux estimates were investigated. We retrieved the fluxes of 16 OOMs, which displayed highly variable exchange behavior and fell into three categories: deposition-dominated, emission-dominated, and bidirectional exchange. Campaign-averaged daily deposition flux 4.6 µmol m −2 d −1 of 16 OOM was 16.3 % of HNO 3 deposition flux, but was higher than daily emission flux of OOMs by a factor of 2.2. Formic acid accounted for 66.2 % and 84.9 % of the summed deposition and emission fluxes of the 16 OOMs, respectively. Other appreciable contributors included isoprene-derived organonitrate C 4 H 7 NO 5 , peracetic acid C 2 H 4 O 3 , and nitrophenol C 6 H 5 NO 3 . OOM fluxes at this urban site were generally lower than those previously reported above forest canopies, although the differences were typically within one order of magnitude. This work provides key methodological guidance and observational constraints for surface-atmosphere exchange of underrepresented reactive carbons.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"5 1","pages":"13213-13225"},"PeriodicalIF":6.3,"publicationDate":"2026-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149021875","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}

引用次数: 0

Chemical characterization and source apportionment of carbonaceous aerosols during post-monsoon biomass burning and Diwali at an upwind site of Delhi 德里逆风地区季风后生物质燃烧和排灯节期间碳质气溶胶的化学特征和来源分析

IF 6.3 1区地球科学

Atmospheric Chemistry and Physics Pub Date : 2026-09-21 DOI: 10.5194/acp-26-13227-2026

Vasu Singh,Dilip Ganguly,Jaswant Rathore,Lokesh Kumar Sahu,Ravi Kumar Kunchala,Sagnik Dey

{"title":"Chemical characterization and source apportionment of carbonaceous aerosols during post-monsoon biomass burning and Diwali at an upwind site of Delhi","authors":"Vasu Singh,Dilip Ganguly,Jaswant Rathore,Lokesh Kumar Sahu,Ravi Kumar Kunchala,Sagnik Dey","doi":"10.5194/acp-26-13227-2026","DOIUrl":"https://doi.org/10.5194/acp-26-13227-2026","url":null,"abstract":"Severe post-monsoon haze in Delhi-NCR poses air-quality and health risks and reflects regional and urban emissions. Sonipat lies along the principal transport corridor linking the agricultural burning regions of Punjab and Haryana with Delhi and serves as an intermediate receptor for regional pollution. However, source apportionment at upwind locations remains limited. To address this gap, we measured composition-based PM 2.5 , defined as non-refractory PM 2.5 plus equivalent black carbon, at Sonipat from 25 October to 15 November 2023 using a Time-of-Flight Aerosol Chemical Speciation Monitor and a multi-wavelength Aethalometer. Positive matrix factorization, black-carbon apportionment, and trajectory and wind analyses were used to identify carbonaceous aerosol sources and examine their evolution during haze, non-haze, and Diwali periods. Two severe haze episodes occurred, with composition-based PM 2.5 exceeding 300 µg m −3 . Organic aerosol contributed 65 % of non-refractory PM 2.5 , and its daily mean reached nearly 140 µg m −3 . Oxygenated organic aerosol accounted for approximately 57 %–60 % of total organic aerosol, with more-oxidized oxygenated organic aerosol reaching 42.8 µg m −3 during peak haze, indicating substantial secondary processing and accumulation. Under the reference absorption Ångström exponent pair, biomass- or solid-fuel-related eBC accounted for approximately 78 % of the campaign-integrated eBC burden, although the quantitative source split was sensitive to the assumed exponents. Northwestern transport signatures and co-variation of eBC bb with biomass-burning and solid-fuel organic aerosol indicate an important regional combustion influence. These findings show that carbonaceous aerosol was already present at this receptor before further interaction with Delhi emissions and support coordinated regional controls alongside sustained urban emission reductions.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"9 1","pages":"13227-13252"},"PeriodicalIF":6.3,"publicationDate":"2026-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149021876","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}

引用次数: 0

Improving aerosol–radiation interactions in the operational forecasting system – AIRWISE 改进业务预报系统AIRWISE中气溶胶与辐射的相互作用

IF 6.3 1区地球科学

Atmospheric Chemistry and Physics Pub Date : 2026-09-21 DOI: 10.5194/acp-26-13189-2026

Sumit Kumar,Gaurav Govardhan,Sreyashi Debnath,Avinash N. Parde,Sandeep Wagh,Jimy Dudhia,Sachin D. Ghude

{"title":"Improving aerosol–radiation interactions in the operational forecasting system – AIRWISE","authors":"Sumit Kumar,Gaurav Govardhan,Sreyashi Debnath,Avinash N. Parde,Sandeep Wagh,Jimy Dudhia,Sachin D. Ghude","doi":"10.5194/acp-26-13189-2026","DOIUrl":"https://doi.org/10.5194/acp-26-13189-2026","url":null,"abstract":"Accurate representation of aerosol optical properties remains a key uncertainty in aerosol–radiation interactions (ARIs) in numerical weather prediction models. Operational air pollution forecasting systems use globally prescribed complex refractive indices (RIs) that inadequately represent regional aerosol composition, inducing biases in ARIs and boundary layer evolution. In this study, updated and more realistic RIs of aerosols over Delhi are implemented within the Air Quality Warning and Integrated Decision Support System for Emissions (AIRWISE) to quantify their radiative and meteorological impacts during the October 2023–January 2024 season. Sensitivity experiments with RIs of different aerosol species indicate reduction in downwelling shortwave radiation at the surface (SWDOWN) by up to ∼80 W m −2 (diurnally ∼43 W m −2 ) during a severe post-monsoon episode. This radiative perturbation decreases surface temperature (∼0.2 °C), near-surface wind speed (∼0.4 m s −1 ), and boundary layer height (∼200 m), while increasing daytime humidity (3 %–4 %). Comparable sensitivity is observed during an extreme winter episode under stagnant, humid conditions favorable for haze persistence. Seasonally, monthly mean SWDOWN decreases by 25–37 W m −2 relative to the control simulation, accounting for ∼1/4 to 1/3 of the total ARIs in clear sky conditions. Evaluation against surface radiation measurements from Winter Fog Experiment (WiFEX 2023–2024) at Indira Gandhi International Airport, Delhi shows substantial bias reduction in December 2023 (62 %) and January 2024 (35 %). The revised radiative forcing systematically modifies near-surface thermodynamics and increases PM 2.5 concentrations, thereby altering pollution–meteorology feedback in highly polluted urban environments.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"91 1","pages":"13189-13211"},"PeriodicalIF":6.3,"publicationDate":"2026-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149021874","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}

引用次数: 0

Continental pollutants modulate organic nitrogen and light absorption of marine organic aerosols over East Asian marginal seas 大陆污染物调节东亚边缘海域有机氮和海洋有机气溶胶的光吸收

IF 6.3 1区地球科学

Atmospheric Chemistry and Physics Pub Date : 2026-09-18 DOI: 10.5194/acp-26-13175-2026

Chao Yu,Lin Zheng,Yujue Wang,Meijing Guo,Xu Yu,Yuqi Guo,Sisi Song,Kyoung-Soon Jang,Xiaohong Yao,Jian Zhen Yu,Huiwang Gao

{"title":"Continental pollutants modulate organic nitrogen and light absorption of marine organic aerosols over East Asian marginal seas","authors":"Chao Yu,Lin Zheng,Yujue Wang,Meijing Guo,Xu Yu,Yuqi Guo,Sisi Song,Kyoung-Soon Jang,Xiaohong Yao,Jian Zhen Yu,Huiwang Gao","doi":"10.5194/acp-26-13175-2026","DOIUrl":"https://doi.org/10.5194/acp-26-13175-2026","url":null,"abstract":"Organic nitrogen (ON) in marine aerosols is not only an important fraction of atmospheric nitrogen deposition but also a vital contributor to light-absorbing organic aerosols. However, observational evidence is lacking on the driving factors of ON formation or its role in organic aerosol absorption, especially in marine atmosphere. Here, shipboard observations were conducted in spring, summer, and autumn over the Yellow Sea and Bohai Sea (YBS) to understand the spatiotemporal distributions and sources of aerosol ON over East Asian marginal seas. Aerosol ON was 0.35 ± 0.25 µg N m −3 , accounting for 4 %–60 % of total nitrogen across seasons. Concentrations of ON were the highest in autumn due to severe impacts of anthropogenic pollutants, followed by those in spring and summer. Anthropogenic secondary pollutants (aged biomass burning and secondary nitrate formation) contributed 36 %–76 % of ON, 46 %–83 % of water-soluble ON, and 39 %–89 % of water-insoluble ON. In spring, 55 % of ON, 45 % of water-soluble ON, and 54 % of water-insoluble ON were attributed to dust, and its contribution increased to > 80 % during a dust episode. In summer, marine sources associated with biological activity were important for aerosol ON formation. Nitrogen-containing organic compounds played vital roles in regulating light absorption by organic aerosols over the YBS. Elevated organic aerosol absorption was attributed not only to higher ON concentrations but also to increased absorption capability at higher ON / OC ratios. Our results highlight that transported continental ON drove the light absorption by marine organic aerosols over marginal seas.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"55 1","pages":"13175-13188"},"PeriodicalIF":6.3,"publicationDate":"2026-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149021878","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}

引用次数: 0

An observational perspective on precipitation efficiency of mesoscale convective systems over the Asian Monsoon Region 亚洲季风区中尺度对流系统降水效率的观测视角

IF 6.3 1区地球科学

Atmospheric Chemistry and Physics Pub Date : 2026-09-18 DOI: 10.5194/acp-26-13157-2026

Thabo Makgoale,Sylvia Sullivan,Julia Kukulies

{"title":"An observational perspective on precipitation efficiency of mesoscale convective systems over the Asian Monsoon Region","authors":"Thabo Makgoale,Sylvia Sullivan,Julia Kukulies","doi":"10.5194/acp-26-13157-2026","DOIUrl":"https://doi.org/10.5194/acp-26-13157-2026","url":null,"abstract":"This study investigates the precipitation efficiency ( ε ) of tropical mesoscale convective systems (MCSs) using satellite-based precipitation rates (P˙) and reanalysis cloud, ice, and liquid water paths (CWP, IWP, LWP). We define ε as the ratio of P˙ to CWP, following Li et al. (2022), and phase-partition it using IWP and LWP. We calculate these metrics for a total of 1321 MCSs tracked by the Python FLEXible Object TRacKeR (PyFLEXTRKR) algorithm and focus on southern Asia during monsoon season, given its frequent MCS occurrence. We first look at spatial distributions, analyzing longitudinal and latitudinal trends in MCS versus non-MCS ε . MCS ε values are 50 % higher than ε from non-MCS convection on average and increase from north to sorth and from west to east along monsoonal moisture gradients. Decompositions of ε across different regions of the MCSs indicate that the highest ε consistently occurs within the core, followed by the cold and then warm anvils. Scaling ε by MCS area shows that all ε metrics increase with area up to an MCS effective diameter of 160 km. This trend is consistent with enhanced ice growth associated with deeper clouds and stronger convective organization in larger MCSs, before ε decreases again in the largest systems where cloud ice growth has reached its maximum. In contrast, all ε metrics increase monotonically with MCS depth, indicating that deeper systems convert cloud condensate into surface precipitation more efficiently without the non-monotonicity observed in the ε -area scalings. Finally, ε increases rapidly during the first ∼ 20 % of the MCS lifecycle and decreases more gradually during the remaining decay phase – consistent with our scalings and reflecting enhanced efficiency during periods of system growth, expansion, and deepening.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"3 1","pages":"13157-13173"},"PeriodicalIF":6.3,"publicationDate":"2026-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149021877","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}

引用次数: 0

Enhanced nocturnal N 2 O 5 -ClNO 2 chemistry in Delhi under reduced NO conditions 在减少NO的条件下，德里夜间二氧化氮-二氧化氯化学增强

IF 6.3 1区地球科学

Atmospheric Chemistry and Physics Pub Date : 2026-09-17 DOI: 10.5194/acp-26-13121-2026

Yijing Chen,Cheng Wu,Epameinondas Tsiligiannis,Ravi Kant Pathak,Jan B. C. Pettersson,Harsh Raj Mishra,Gazala Habib,Geetam Tiwari,Kebin He,Jingkun Jiang,Mattias Hallquist

{"title":"Enhanced nocturnal N\u0000 2\u0000 O\u0000 5\u0000 -ClNO\u0000 2\u0000 chemistry in Delhi under reduced NO conditions","authors":"Yijing Chen,Cheng Wu,Epameinondas Tsiligiannis,Ravi Kant Pathak,Jan B. C. Pettersson,Harsh Raj Mishra,Gazala Habib,Geetam Tiwari,Kebin He,Jingkun Jiang,Mattias Hallquist","doi":"10.5194/acp-26-13121-2026","DOIUrl":"https://doi.org/10.5194/acp-26-13121-2026","url":null,"abstract":"Nitryl chloride (ClNO 2 ) is an important Cl⚫ precursor, originating from the heterogeneous reactions of dinitrogen pentoxide (N 2 O 5 ) on chloride-containing particles. This N 2 O 5 -ClNO 2 chemical process plays critical roles in chloride activation, nitrate formation, and thus air pollution. Here we present field measurements made in the early springtime of 2023 in Delhi and compare with a previous study conducted during the winter of 2019. We found elevated nocturnal levels of N 2 O 5 and ClNO 2 , averaging 13 and 80 ppt, respectively, which are approximately doubled compared to observations in 2019. This change is primarily driven by the reduced nighttime NO levels, from 124 ± 25 ppb in 2019 to 44 ± 9 ppb in 2023. In addition, the chloride concentration (nighttime average 4.7 µg m −3 ) in Delhi is among the highest reported globally, driving efficient conversion of N 2 O 5 to ClNO 2 . Decreased NO and elevated ClNO 2 levels lead to higher NO 3 ⚫ and Cl⚫ production that promote the oxidation of organics. Consistently, we observed increased fractions of gaseous nitrogen- and chlorine-containing organic products and a higher oxidation state of the organic aerosols. Our findings highlight the need for increased attention to atmospheric secondary pollution and stringent anthropogenic chlorine emissions control under reduced NO x conditions in Delhi.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"54 1","pages":"13121-13137"},"PeriodicalIF":6.3,"publicationDate":"2026-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149021880","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}

引用次数: 0

Evidence for the impact of fire activity on daily variations of IASI mid-tropospheric CO 2 anomalies at 8–11 km over South America: a pyroconvective fingerprint 火活动对南美洲上空8-11公里处IASI对流层中层CO 2异常日变化影响的证据：热对流指纹

IF 6.3 1区地球科学

Atmospheric Chemistry and Physics Pub Date : 2026-09-17 DOI: 10.5194/acp-26-13103-2026

Victor Bon,Cyril Crevoisier,Virginie Capelle

{"title":"Evidence for the impact of fire activity on daily variations of IASI mid-tropospheric CO\u0000 2\u0000 anomalies at 8–11 km over South America: a pyroconvective fingerprint","authors":"Victor Bon,Cyril Crevoisier,Virginie Capelle","doi":"10.5194/acp-26-13103-2026","DOIUrl":"https://doi.org/10.5194/acp-26-13103-2026","url":null,"abstract":"Biomass burning is a major, highly variable source of atmospheric CO 2 , but its impact on the free troposphere remains difficult to quantify because of uncertainties in injection heights and transport. In the tropics, intense fires can trigger pyroconvective plumes that loft combustion products to the mid- and upper troposphere. However, most fire emission inventories and global CO 2 inversions still assume simplified vertical distributions of CO 2 emitted by fires. Weighted columns of CO 2 retrieved from remote sensing instruments that are sensitive to such high-altitude enhancements can inform of such dynamics. Here we combine mid-tropospheric CO 2 (MT-CO 2 ) retrievals from three IASI instruments with GOES-16 observations of Fire Radiative Energy (FRE) to link daily MT-CO 2 anomalies observed by IASI at 8–11 km altitude to South American fire activity during the 2020 burning season, while accounting for long-range horizontal transport of anomalies. From August–October 2020, about 66 % of the detected anomalies originate from long-range or unknown sources and are discarded. For the remaining anomalies attributed to local fires, 72 h back trajectories do intersect with at least one active fire detection for 75 % of them. Their daily sum co-varies strongly with FRE, with the ratio between the two depending on the dominant horizontal transport regime. A comparison with the CAMS inversion-optimised CO 2 product (v23r1), sampled with the IASI vertical weighting, shows that the model fails to reproduce both the amplitude and structure of the observed anomalies. Overall, our results demonstrate that IASI MT-CO 2 anomalies carry an observational fingerprint of tropical fire activity.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"9 1","pages":"13103-13119"},"PeriodicalIF":6.3,"publicationDate":"2026-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149021883","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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