Atmospheric Chemistry and Physics最新文献

{"title":"Forest and bioenergy expansion amplifies climate warming by accelerating regional cloud loss","authors":"Nanjian Liu,Zhixin Hao,Siyou Xia,Peng Zhao","doi":"10.5194/acp-26-14133-2026","DOIUrl":"https://doi.org/10.5194/acp-26-14133-2026","url":null,"abstract":"Land use and cover change (LUCC) can exacerbate cloud-mediated climate warming, yet long-term cloud responses to contrasting LUCC pathways remain poorly quantified. Here, we perform transient simulations based on the fully coupled Community Earth System Model (CESM) under the SSP1-2.6 scenario to quantify how long-term cloud trends respond to large-scale idealized afforestation (AF50, conversion of grassland or shrubland to forest), idealized bioenergy expansion (BE50, sugarcane expansion), and realistic afforestation (REAL). AF50 drives a pronounced vertical restructuring of cloud trends, steepening mid-level cloud decline and accelerating low-level cloud loss from −0.0153 ± 0.0030 % yr −1 in the control simulation (CTL) to −0.0175 ± 0.0036 % yr −1 , corresponding to 1.14 times the CTL rate globally and 1.52 times over land. Concurrently, it amplifies the global increase in high-level clouds by a factor of 1.5 and accelerates total cloud cover loss over land. Bioenergy expansion induces a similar but weaker vertical shift, whereas realistic afforestation slows the loss rate of low- and mid-level clouds and suppresses regional warming. Interpretable machine learning identifies changes in relative-humidity trends as the highest-ranked predictor of LUCC-induced changes in low-level cloud trends, with relative importance values of 20.4 %, 20.4 %, and 15.3 % under AF50, BE50, and REAL, respectively. The simulated low-level cloud response is consistent with surface darkening reducing albedo, increasing sensible heat flux, deepening the planetary boundary layer, enhancing dry-air entrainment, and raising the lifting condensation level relative to the boundary-layer top, thereby suppressing low-level cloud formation. The cloud response is also modulated by remote atmospheric adjustment. The accelerated depletion of low-level clouds strengthens positive shortwave cloud radiative forcing, while the concurrent increase in high-level clouds enhances longwave warming, together amplifying regional warming hotspots. These results demonstrate that larger-scale forest expansion does not necessarily provide greater climate cooling benefits; the sign and magnitude of the outcome depend not only on the latitude band of land conversion but, more critically, on the type of land conversion.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"14 1","pages":"14133-14163"},"PeriodicalIF":6.3,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149151036","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}

{"title":"Physics-constrained transfer learning with a spectral-fidelity-preserving model for satellite remote sensing applications","authors":"Min Min,Qiang Yu,Jun Li,Han Lin,Yunheng Xue,Xinran Xia,Di Di,Bo Li,Peng Zhang","doi":"10.5194/acp-26-14205-2026","DOIUrl":"https://doi.org/10.5194/acp-26-14205-2026","url":null,"abstract":"Accurate spectral transformation across satellite sensors with similar but different spectral response functions (SRFs) is essential for applying the same retrieval algorithms. A novel physics-constrained transfer learning (TL) framework is developed for transferring satellite radiance observations across different sensors while preserving physical consistency. It integrates a core Spectral-Fidelity-Preserving (SFP) model based on extensive radiative transfer simulations, allowing broad adaptability for radiance transformation under diverse satellite observational conditions. Sensitivity experiments demonstrate the robustness of the TL framework relating to radiometric calibration uncertainties, particularly in infrared (IR) channels, and further highlight the critical role of SRF similarity between sensors. We further establish practical SRF-similarity thresholds – an allowable scaling-factor range and central-wavenumber-shift limits that are stricter for IR window channels – that support reliable radiance transfer (see Sect. 3.2 for details). Application to radiance observations from Fengyun-4A/B (FY-4A/B) geostationary (GEO) satellites explicitly indicates that the TL approach improves retrieval accuracy for key geophysical parameters such as cloud amount profile and quantitative precipitation estimation, when compared with results obtained without applying TL. Thus, the TL approach enhances cross-satellite data consistency and provides a practical tool for operational satellite data applications (e.g., transferring algorithms developed for FY-4A to FY-4B without operational interruption). It is worth noting that the FY-4A/FY-4B experiments presented here demonstrate retrieval-model transfer, validated against independent downstream satellite products. Beyond retrieval-model transfer, the framework can also support direct radiometric calibration transfer by propagating an absolute calibration reference at the radiance level between different spaceborne imagers.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"9 1","pages":"14205-14228"},"PeriodicalIF":6.3,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149151037","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}

{"title":"Light absorption properties and composition of water-soluble brown carbon in North China Plain: implication for an enhancing role of nitrogenous organic compounds","authors":"Can Wu,Huijun Zhang,Kehan Sun,Rongjie Li,Ziting Yan,Yubao Chen,Zheng Li,Binyu Xiao,Yanqin Ren,Gehui Wang","doi":"10.5194/acp-26-14229-2026","DOIUrl":"https://doi.org/10.5194/acp-26-14229-2026","url":null,"abstract":"Brown carbon (BrC), an efficiently light-absorbing carbonaceous aerosol, exerts significant impacts on the global energy budget and regional climate, attracting growing scientific attention. To advance understanding of the spatial variability of atmospheric BrC and its dominant formation pathways in the North China Plain (NCP), light absorption properties, chemical composition and formation process of the water-soluble BrC in 2023 winter were investigated by conducting simultaneous measurements at five sites across the NCP, namely, Beijing, Tianjin, Luancheng (rural site), Handan and Jinan. Our results showed that the average light absorption coefficient at 365 nm (abs 365 ) in Luancheng was approximately 1.1–3.5 times higher than those in urban ones. However, mass absorption efficiency displayed a distinctly different spatial pattern, with the strongest light-absorptivity (1.40 ± 0.02 m 2  g −1 ) recorded in Jinan. Notably, average abs 365 in four urban sites exhibited a decline of ∼ 45 % from 2018 to 2023 compared to those previous observations. Furthermore, the light-absorptivity of water-soluble BrC was enhanced from clean to haze period at the most sampling sites along with the increasing N:C ratio, indicating that nitrogenous organic compounds (NOCs) were important chromophores of water-soluble BrC in the NCP. Additionally, These NOCs were found to be closely associated with aqueous reactions, in which ammonia played an important role. These results elucidate the substantial contribution of NOCs to atmospheric BrC in the NCP, and further suggest a potentially important role of NH 3 emission control in alleviating wintertime haze and BrC pollution under moist conditions in this region.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"54 1","pages":"14229-14243"},"PeriodicalIF":6.3,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149151059","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}

{"title":"Estimating Twomey forcing sensitivity to aerosol plume spreading rates","authors":"Lucas A. McMichael,Ehsan Erfani,Robert Wood,Knut von Salzen","doi":"10.5194/acp-26-14111-2026","DOIUrl":"https://doi.org/10.5194/acp-26-14111-2026","url":null,"abstract":"The amount of sunlight that reaches Earth's surface can be reduced by increasing cloud droplet number and decreasing droplet size (i.e., Twomey forcing), a central idea underpinning the Marine Cloud Brightening strategy. Cloud albedo depends nonlinearly on cloud droplet concentration, meaning the spatial extent of aerosol plumes could be an important constraint on the brightening potential. In this study, horizontal aerosol spreading is simulated using a Langevin particle model driven by a library of realistic, 2 d Large Eddy Simulations (LES) spanning the meteorological and aerosol phase space of northeast Pacific stratocumulus. The 2D reflectance fields from the LES are superimposed onto the 2D perturbed aerosol concentrations to calculate the 2D Twomey forcing response. The Day 1 and Day 2 LES regimes have distinct meteorological, aerosol, and turbulence characteristics associated with equatorward movement of the LES domain. Our results indicate that the Day 2 regime has substantially faster plume spreading than Day 1, with ensemble median differences exceeding 2 km h −1 . Despite these differences, Twomey forcing is insensitive to the natural variability in spreading rate. This study suggests that Twomey forcing is resilient to variations in meteorology, aerosols, and turbulence, with its efficacy governed primarily by aerosol lifetime and assumptions surrounding cloud adjustments. Although the natural variation in spreading rate does not materially affect Twomey forcing, idealized plume spreading simulations suggest that current GCM assumptions of an infinitely fast spreading rate could lead to a 10 %–200 % overestimation of cooling.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"36 1","pages":"14111-14132"},"PeriodicalIF":6.3,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149151034","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}

{"title":"Chemical characterization and source apportionment of PM\u0000 10\u0000 in Belgrade, Serbia: influence of local and regional anthropogenic and natural sources","authors":"Bojana Petrović,Andres Alastuey,Karl Espen Yttri,Marco Pandolfi,Maja Jovanović,Bojan Radović,Renata Kovačević,Danka B. Stojanović,Miloš Davidović,Stephen M. Platt,Alena Bartonova,Milena Jovašević-Stojanović","doi":"10.5194/acp-26-14165-2026","DOIUrl":"https://doi.org/10.5194/acp-26-14165-2026","url":null,"abstract":"Substantial efforts and improvements in air quality across Europe lowered levels of air pollutants including particulate matter (PM) in the last decades. However, significant proportion of the European population still lives in areas exceeding WHO recommendations, especially in Northern Italy, Balkans, and Eastern Europe, including Serbia. Targeted PM mitigation strategies require extensive air quality monitoring and modelling including source apportionment (SA) studies. In the past, numerous SA studies were conducted for Belgrade city, capital of Serbia. Nevertheless, comparisons across the results are difficult, as they encompass different datasets of pollutants contained in PM fractions such as elements and/or ions and/or PAHs. Here, the aim is to offer a broader insight on PM 10 sources at an urban background site in Belgrade by including 34 species as input variables for SA (carbonaceous aerosols, elements, ions and specific organic tracers). For SA, the USEPA PMF 5.0 software was applied. The factor that dominated PM 10 mass was biomass burning (21 %), primarily during heating season, followed by ammonium sulphate (18 %) and mineral dust (17 %). A mixed traffic and industrial activity accounted for 15 % of PM 10 mass while contribution of factors from biological origin, primary biological aerosol particles and biogenic secondary organic aerosols from isoprene, was 10 % each. Mixed factor of long-range transport and road salt/local combustion contributed to the PM 10 mass 9 %. This analysis provides more detailed perspective on the composition and sources of PM 10 in Belgrade, both from anthropogenic and natural, including biological origin. These findings are valuable for defining targeted PM 10 mitigation strategies.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"10 1","pages":"14165-14184"},"PeriodicalIF":6.3,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149151033","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}

{"title":"NeuPlume: generative inversion of atmospheric point-source emissions from sparse observations","authors":"Lei Wang,Xin Ma","doi":"10.5194/acp-26-14185-2026","DOIUrl":"https://doi.org/10.5194/acp-26-14185-2026","url":null,"abstract":"Inverting point-source emissions from sparse atmospheric observations is difficult because emission rate, release height, wind speed, turbulence, and plume morphology can compensate for one another. We present NeuPlume, a neural-physical framework that formulates inversion as observation-guided generation and selection of complete three-dimensional concentration fields. A Lagrangian stochastic model builds a scenario-specific forward library, a conditional neural field compresses the simulated fields, and a latent diffusion model learns their conditional distribution. During inversion, diffusion posterior sampling generates candidate fields on a coarse-to-fine parameter grid, and NeuPlume returns the parameters and field that best match the observations. Across 30 synthetic cases, the selected fields achieve a mean spatial correlation of 0.942 and a mean emission-rate error of 13.6 %. Matched stress tests show that both observation geometry and transport-model fidelity govern inversion quality: trajectory-concentrated sampling weakens full-field reconstruction, while unrepresented transport alters parameter identification and, for effective plume rise, also degrades field reconstruction. Applied to four UAV methane transects above a coal-mine ventilation shaft, NeuPlume yields known- U minimum-loss emission estimates of 5.27–15.85 kt yr −1 and exposes wind-speed and height-boundary sensitivities under model mismatch. NeuPlume thus provides an extensible methodology for jointly estimating source parameters and concentration fields: additional transport regimes can be incorporated through regime-specific simulation ensembles and neural-model retraining.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"69 1","pages":"14185-14203"},"PeriodicalIF":6.3,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149151035","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}

{"title":"EarthCARE reveals details on the role of rain in closed-to-open cell transitions","authors":"Johanna Mayer,Daniele Gasbarra,Robin J. Hogan,Edward Malina,Shannon L. Mason,Blanka Piskala Gvozdikova","doi":"10.5194/acp-26-14085-2026","DOIUrl":"https://doi.org/10.5194/acp-26-14085-2026","url":null,"abstract":"The mesoscale organisation of marine stratocumulus clouds into closed and open cells strongly affects cloud albedo and thus their cooling effect on climate, yet the processes governing transitions between these regimes remain incompletely understood. The EarthCARE satellite provides collocated observations of cloud mesoscale structure from the Multi-Spectral Imager (MSI) together with vertically resolved cloud and precipitation measurements from the Atmospheric Lidar (ATLID) and Cloud Profiling Radar (CPR), enabling detailed characterization of stratocumulus cloud microphysics. We apply a convolutional neural network to MSI scenes to identify closed and open cells and relate these classifications to EarthCARE microphysical retrievals from the synergy of ATLID, CPR, and MSI. Open cells exhibit substantially lower droplet number concentrations ( N d ), greater variability in liquid water path (LWP) and droplet sizes ( r e ), and more frequent and heavier precipitation, although light drizzle is also common in closed cells. To investigate closed-to-open cell transitions, we combine EarthCARE overpasses with GOES/ABI geostationary imagery and ERA5-driven trajectories to track cloud scenes and determine transition timing. This combined approach allows us to reconstruct the temporal evolution of cloud properties around transitions. We find that LWP and rain amounts increase in closed cells up to 25 h before transitions, followed by decreasing N d and increasing r e , while cloud vertical structure remains largely unchanged. These findings support a precipitation-linked transition pathway, potentially triggered by enhanced boundary-layer moisture and amplified by aerosol scavenging–rain feedback. This new observational evidence advances our understanding of stratocumulus breakup with implications for the cooling effect of these clouds.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"11 1","pages":"14085-14110"},"PeriodicalIF":6.3,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149151061","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}

{"title":"Isotopic composition of aerosol iron from anthropogenic sources: implications for source apportionment of aerosol iron","authors":"Yifan Zhang,Guanhong Zhu,Rui Li,Mingyuan Liu,Yi Yang,Tianyu Zhang,Yizhu Chen,Jinlong Ma,Xinming Wang,Mingjin Tang","doi":"10.5194/acp-26-14073-2026","DOIUrl":"https://doi.org/10.5194/acp-26-14073-2026","url":null,"abstract":"Aerosol iron (Fe) significantly impacts human health, atmospheric chemistry and marine biogeochemistry. The stable isotope ratio of Fe, typically reported as δ 56 Fe, has emerged as a promising method for source apportionment of total and soluble aerosol Fe. However, the δ 56 Fe endmember values remain poorly constrained for aerosol Fe from various non-dust sources, impeding the application of Fe isotopes in atmospheric research. This work measured isotopic compositions for aerosol Fe from desert dust and several anthropogenic sources. The average δ 56 Fe was determined to be +0.14 ‰ ± 0.10 ‰ for the seven dust samples we examined, in good agreement with previous work. We found that different anthropogenic aerosols exhibit a wide range of Fe isotopic composition. Compared to desert dust, the average δ 56 Fe was found to be higher for power plant coal fly ash (+0.26 ‰ ± 0.18 ‰, n =28), slightly lower for steelwork fly ash (−0.07 ‰ ± 0.41 ‰, n =18), and considerably lower for biofuel burning aerosol (−0.28 ‰ ± 0.39 ‰, n =11). In addition, the average δ 56 Fe was determined to be +0.20 ‰ ± 0.12 ‰ for municipal incineration fly ash ( n =2), +0.38 ‰ ± 0.13 ‰ for heavy oil bottom ash ( n =1), and +0.08 ‰ ± 0.13 ‰ for certificated urban particulate matter sample ( n =1). We suggest that not all the anthropogenic aerosol Fe is isotopically lighter than natural dust Fe, in contrast to what is conventionally assumed. Our findings also imply that Fe isotope-based source apportionment must account for the δ 56 Fe endmember variability both among and within different anthropogenic aerosols. Overall, our work substantially improves our ability to constrain δ 56 Fe endmember values for various anthropogenic sources.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"10 1","pages":"14073-14084"},"PeriodicalIF":6.3,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149151060","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}

{"title":"Constraints on NO\u0000 \u0000 x\u0000 \u0000 emission in Thailand using GEMS satellite data","authors":"Worapop Thongsame,Daven K. Henze,Gabriele Pfister,Rajesh Kumar,Mary Barth","doi":"10.5194/acp-26-14051-2026","DOIUrl":"https://doi.org/10.5194/acp-26-14051-2026","url":null,"abstract":"Nitrogen oxides (NOx=NO+NO2) are key pollutants that contribute to ozone and secondary aerosol formation, posing environmental and health risks. Accurate simulation and forecasting of NO x pollution is essential for developing mitigation strategies. Local inventories in Thailand are infrequently updated, leading researchers to use global inventories such as CAMS-GLOB-ANT for simulation. Global inventories carry uncertainties due to assumptions in emission factors, outdated activity data, and coarse temporal resolution. To address these limitations, this study applies a top-down approach to update NO x emissions in Thailand using the iterative finite difference mass balance (IFDMB) method. Tropospheric NO 2 vertical column densities (VCDs) from GEMS version 3 are integrated with the WRF-Chem to refine CAMS-GLOB-ANT emissions for September 2023. The simulations with posterior emissions are evaluated against TROPOMI NO 2 VCDs and surface NO x concentration. Results show that the baseline simulation overestimates NO 2 VCDs across Thailand compared with GEMS, except in North Thailand. GEMS reports substantially higher NO 2 than TROPOMI – particularly over Lampang – reflecting retrieval uncertainty associated with the a priori profiles used in version 3. Consequently, IFDMB reduces NO x emissions across most regions but increases in the North. The increase is attributed primarily to a retrieval artifact rather than to a genuine emission underestimate. Baseline NO x emissions in Thailand are 35 852 Mg per month with North Thailand and 30 699 Mg per month without North. Our posterior emissions over three IFDMB schemes are 25 994, 34 808, and 36 870 Mg per month with North, and 15 376, 26 523, and 27 087 Mg per month without North. These adjustments improve model bias and error relative to GEMS. However, when evaluated against TROPOMI, we find an increase in the bias for North Thailand, likely due to discrepancies between GEMS and TROPOMI retrievals. These discrepancies highlight the importance of future retrieval algorithm improvement and calibration across satellite products. Comparisons to surface observations indicate that IFDMB shifts the NO x peak to later than observations. This is because observations are strongly influenced by local transportation sources, which are hard to observe and retrieved by GEMS and the model, respectively.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"4 1","pages":"14051-14072"},"PeriodicalIF":6.3,"publicationDate":"2026-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149088020","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}

{"title":"Tropical belt expansion and its impacts on climate variability in the Mediterranean from 1980 to 2022","authors":"Mohamed Darrag,Shuanggen Jin,Andrés Calabia,Aalaa Samy,Ivan Radevski,Ali M. Radwan","doi":"10.5194/acp-26-14031-2026","DOIUrl":"https://doi.org/10.5194/acp-26-14031-2026","url":null,"abstract":"This paper explores the long-term variability of climatic parameters over the Mediterranean region and their relationship with tropical belt expansion by investigating observational and reanalysis data from January 1980 to December 2022 through multiple approaches, including correlation, linear regression, and singular value decomposition (SVD) analysis. The lapse rate tropopause height exhibits upward trends of approximately 80.58 m per decade. Concurrently, the tropical belt shows a poleward expansion of approximately 0.14 and 0.27° per decade, estimated using the tropopause drop and tropopause gradient methods, respectively. The tropical edge latitudes (TELs) of both applied approaches show an evident seasonal variation. In addition, the two TEL definitions exhibit consistent correlation patterns with surface temperature (Ts), lower tropospheric temperature (Trp-1), upper tropospheric temperature (Trp-2), precipitation, and the Standardized Precipitation Evapotranspiration Index (SPEI). The results of the SVD analysis depict that although the leading mode explains the majority of the covariance between TELs and the examined climatic parameters, the second coupled mode shows more localized spatial structures, with TELs pronouncedly coupling with Ts and Trp-1 in the eastern Mediterranean. Furthermore, Ts and Trp-1 have significant increasing trends, which are abundant in the eastern Mediterranean. On the other hand, both precipitation and SPEI exhibit downward trends. Over the Mediterranean region, climatic parameters show an apparent spatial and temporal variation. The results confirm the linkage between climatic parameters' trends and variability with the TELs' variability patterns over the study area, especially in the eastern Mediterranean region.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"73 1","pages":"14031-14050"},"PeriodicalIF":6.3,"publicationDate":"2026-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149088023","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}