Journal of Geophysical Research: Atmospheres最新文献

{"title":"The Impact of CO2-Driven Vegetation Changes on the Future of Flash Drought in the Northern Hemisphere","authors":"Ali Fallah,&nbsp;Mathew A. Barlow,&nbsp;Jeffrey Basara,&nbsp;Gabriel J. Kooperman,&nbsp;Caleb Kohane,&nbsp;Christopher B. Skinner","doi":"10.1029/2025JD043882","DOIUrl":"https://doi.org/10.1029/2025JD043882","url":null,"abstract":"<p>Vegetation plays a crucial role in soil moisture regulation and the development of rapid-onset droughts known as flash droughts. We use climate model experiments with the Community Earth System Model (CESM2) to examine how the vegetation response to rising CO₂ impacts projections of future flash drought in the Northern Hemisphere mid-latitudes. By isolating the influences of CO₂ fertilization and CO₂ stomatal conductance effects from CO₂ radiative forcing, we find that: (a) CO₂-induced changes to plant characteristics are of sufficient magnitude to modify flash drought characteristics, (b) CO₂ fertilization effects counteract the CO₂ stomatal conductance effects on projected flash drought occurrence, and (c) the combined influence of the vegetation response to rising CO₂ can either amplify or counteract CO₂ radiative-driven flash drought changes depending on location. In water-limited regions such as the western United States, the Mediterranean Basin, the Middle East, and west/central Asia where CO₂ fertilization dominates and surface vegetation strongly controls water availability, elevated leaf area offsets reductions in stomatal conductance and transpiration, increasing the likelihood of future flash droughts. Vegetation-driven increases in flash drought in these areas are generally aligned in sign with projected increases due to radiative forcing. Conversely, in more energy limited regions such as western Canada, East Asia, and parts of Europe, preserved soil moisture from reduced stomatal conductance and transpiration suppresses flash droughts despite increased leaf area from CO₂ fertilization. These reductions in flash drought from vegetation counteract radiative-driven increases. This study elucidates physical processes underlying projected flash drought development, improving predictive capabilities and mitigation strategies.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 19","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JD043882","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145224497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vertical Velocity and Diabatic Heating Top-Heaviness in the Convective Evolution Over Tropical Oceans","authors":"Yi-Chien Chen,&nbsp;Hirohiko Masunaga","doi":"10.1029/2024JD043054","DOIUrl":"https://doi.org/10.1029/2024JD043054","url":null,"abstract":"&lt;p&gt;Convective heating and vertical motion are closely linked to each other and follow similar evolutionary paths over their convective life cycle. It has not yet been extensively explored, using observation, how such a collaborative evolution changes systematically from region to region over tropical oceans. In this study, the ERA5 reanalysis data and satellite measurements from Tropical Rainfall Measuring Mission Precipitation Radar are analyzed to examine the variability of the large-scale vertical velocity (&lt;i&gt;ω&lt;/i&gt;) and diabatic heating (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;Q&lt;/mi&gt;\u0000 &lt;mn&gt;1&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${Q}_{1}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;) profiles over tropical oceans. Hour-to-hour variability in these variables is examined based on composite time series to delineate the evolution of &lt;i&gt;ω&lt;/i&gt; and &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;Q&lt;/mi&gt;\u0000 &lt;mn&gt;1&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${Q}_{1}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; before and after Global Satellite Mapping of Precipitation (GSMaP) precipitation peaks. Four tropical basins are selected to study regional differences: western Pacific (WP), eastern Pacific (EP), Indian Ocean (IO), and Atlantic Ocean (AO). The composite time series reveal that the &lt;i&gt;ω&lt;/i&gt; and &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;Q&lt;/mi&gt;\u0000 &lt;mn&gt;1&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${Q}_{1}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; distributions align with the typical life cycle of mesoscale convective systems (MCSs). Empirical orthogonal function (EOF) decomposition is applied to the vertical structure of &lt;i&gt;ω&lt;/i&gt; and &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;Q&lt;/mi&gt;\u0000 &lt;mn&gt;1&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${Q}_{1}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; in terms of top-heaviness. The &lt;i&gt;ω&lt;/i&gt; and &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;Q&lt;/mi&gt;\u0000 &lt;mn&gt;1&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${Q}_{1}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; top-heaviness ratio (THR) delineate similar evolutionary curves in that THR enhances as convection intensifies, but the peak hour occurs earlier for &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;sema","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 19","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2024JD043054","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145224165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prolonged Atmospheric Chemical Lifetime of Unsaturated Fatty Acids From Cooking Sources Observed in Beijing During Wintertime","authors":"Wenli Liu,&nbsp;Longkun He,&nbsp;Yatai Li,&nbsp;Peizhao Li,&nbsp;Shiyi Chen,&nbsp;Jing Chen,&nbsp;Yingjun Liu,&nbsp;Mikinori Kuwata","doi":"10.1029/2025JD044172","DOIUrl":"https://doi.org/10.1029/2025JD044172","url":null,"abstract":"<p>Chemical aging of organic aerosol (OA) is an important process for determining its environmental impacts. Previous laboratory and modeling studies have suggested that chemical aging of OA slows at lower temperatures due to increased particle viscosity, which hampers the diffusion of oxidants within the particle phase. However, evidence from field measurements has been lacking. For tackling the issue, we conducted atmospheric measurements of the molecular-level chemical composition of OA using an online instrument in Beijing during wintertime. Unsaturated fatty acids from cooking such as oleic acid were detected. Apparent second-order reaction rate constants (<i>k</i>₂) of oleic acid with O₃ were retrieved from the data, especially focusing on oleic acid emitted during dinnertime. The <i>k</i>₂ values measured at cold winter nights in Beijing were found to be lower by an order of magnitude than those observed from residential cooking experiments at room temperature. The difference is quantitatively consistent with the temperature dependence of <i>k</i>_<i>2</i> for simulated cooking aerosol in previous laboratory studies. This result suggests that the chemical aging of ambient OA is influenced by temperature-induced changes in viscosity, underscoring the need to account for temperature effects when estimating the fate of OA across the broad atmospheric temperature range.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 19","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145224335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of Marine Boundary Layer Clouds Over the Northeast Pacific During the CSET Campaign in E3SM Version 2","authors":"Kyoung Ock Choi,&nbsp;Philip J. Rasch,&nbsp;Robert Wood,&nbsp;Sarah J. Doherty,&nbsp;Hui Wan,&nbsp;Hailong Wang,&nbsp;Shixuan Zhang,&nbsp;Kai Zhang,&nbsp;Mingxuan Wu","doi":"10.1029/2024JD042673","DOIUrl":"https://doi.org/10.1029/2024JD042673","url":null,"abstract":"&lt;p&gt;It is still challenging to reproduce marine boundary layer (MBL) clouds well in large-scale models despite their importance to the Earth's radiation budget and hydrological cycle. This study evaluates representation of the MBL and clouds in the Energy Exascale Earth System Model (E3SM) version 2. This study compares the E3SM simulation results with remote sensing and reanalysis data during the Cloud System Evolution in the Trades (CSET) field campaign to better understand the stratocumulus-to-cumulus cloud transition (SCT) over the northeast Pacific. E3SM results are extracted along the CSET Lagrangian trajectories. The comparison shows that the E3SM simulation applying horizontal wind nudging performs well in reproducing thermodynamic variables of the MBL and evolution trends of cloud variables along the trajectories. However, substantial overestimations of aerosol and cloud drop number &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mfenced&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;N&lt;/mi&gt;\u0000 &lt;mi&gt;d&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mfenced&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $left({N}_{d}right)$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; are observed, which is explained as an issue with version 2 of the model. Cloud fraction (CF) does decrease from the Californian coast to Hawaii in the E3SM simulation, but most CF values indicate either an overcast or almost clear sky, which differs from satellite and reanalysis data. The effect of &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;N&lt;/mi&gt;\u0000 &lt;mi&gt;d&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${N}_{d}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; overestimation on CF evolution is assessed via prescribed-&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;N&lt;/mi&gt;\u0000 &lt;mi&gt;d&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${N}_{d}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; simulations. Those simulations with &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;N&lt;/mi&gt;\u0000 &lt;mi&gt;d&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${N}_{d}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; modifications show negligible CF changes. A comparison of estimated inversion strength (EIS) also shows that the simulated EIS values are similar to those of reanalysis data. Our study suggests that cloud macrophysics and boundary layer processes are more important in improving the simulation to capture the SCT than refining the model's thermodynamics or cl","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 19","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2024JD042673","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145224302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Toward Real-Time Assessment of Infrasound Event Detection Capability Using Deep Learning-Based Transmission Loss Estimation","authors":"A. Janela Cameijo,&nbsp;A. Le Pichon,&nbsp;Y. Sklab,&nbsp;S. Arib,&nbsp;Q. Brissaud,&nbsp;S. P. Näsholm,&nbsp;C. Listowski,&nbsp;S. Aknine","doi":"10.1029/2025JD043577","DOIUrl":"https://doi.org/10.1029/2025JD043577","url":null,"abstract":"<p>Accurate modeling of infrasound transmission loss is crucial for assessing the performance of the International Monitoring System, which monitors compliance with the Comprehensive Nuclear-Test-Ban Treaty by detecting atmospheric explosions. This modeling supports the design and maintenance of the operating monitoring network. State-of-the-art propagation modeling tools enable transmission loss to be finely simulated using atmospheric models. However, the computational cost prohibits the exploration of a large parameter space in operational monitoring applications. To address this, recent studies made use of a deep learning algorithm capable of making transmission loss predictions almost instantaneously. However, the use of nudged atmospheric models leads to an incomplete representation of the medium, and the absence of temperature as an input makes the algorithm incompatible with long-range propagation. In this study, we address these limitations by using both wind and temperature fields as inputs to a neural network, simulated up to 130 km altitude and 4,000 km distance. We exploit convolutional and recurrent layers to capture spatially and range-dependent features embedded in realistic atmospheric models, improving the overall performance. The neural network reaches an average error of 4 dB compared to full parabolic equation simulations and provides epistemic and data-related uncertainty estimates. Its evaluation on the 2022 Hunga Tonga-Hunga Ha'apai volcanic eruption demonstrates its prediction capability using atmospheric conditions and frequencies not included in the training. This represents a significant step toward near real-time assessment of International Monitoring System detection thresholds of explosive sources.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 19","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JD043577","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145224337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Regional Aspects of Observed Temperature and Precipitation Trends in the Western Mediterranean: Insights From a Timescale Decomposition Analysis","authors":"D. A. Campos,&nbsp;M. E. Olmo,&nbsp;P. Cos,&nbsp;Á. G. Muñoz,&nbsp;F. J. Doblas-Reyes","doi":"10.1029/2024JD042637","DOIUrl":"https://doi.org/10.1029/2024JD042637","url":null,"abstract":"<p>The observed warming in the Western Mediterranean (WMed) region over recent decades is projected to continue, outpacing the global average, making the region a prominent climate change hotspot. Even within this relatively small area, the combination of natural climate variability and anthropogenic climate change creates significant spatial variation in extreme climate events. This study analyzes mean seasonal temperature and precipitation trends in the WMed using ECMWF Reanalysis v5 (ERA5) data from 1951 to 2020 taking into consideration the climatic heterogeneity of the region. A non-hierarchical K-Means clustering method was applied to delineate nine climatically homogeneous regions within the WMed. A timescale decomposition analysis was then conducted to disentangle long-term, decadal, and interannual variability components of seasonal data. Results indicate that long-term trends explain most of the total observed variance in temperature (∼65%), whereas interannual natural variability dominates observed precipitation (∼60%). These patterns vary seasonally, with the strongest warming trends along the Mediterranean coast of the Iberian Peninsula and northern Africa in summer and the most significant drying trends in the southwestern Mediterranean during both summer and winter. The influence of different modes of climate variability in the observed trends is assessed and appears to contribute to winter drying, but no evidence was found of its influence on warming trends. This study lays a foundation for future climate change detection and attribution efforts in the WMed, emphasizing the need for sub-regional analysis due to the region's pronounced heterogeneity.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 19","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2024JD042637","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145224336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Inverse Estimation of Urban Methane Emissions Using Both Column and Surface Observations: An OSSE Study","authors":"Jun Zhang,&nbsp;Jia Chen,&nbsp;Sanam Noreen Vardag,&nbsp;Haoyue Tang","doi":"10.1029/2025JD043939","DOIUrl":"https://doi.org/10.1029/2025JD043939","url":null,"abstract":"<p>The magnitudes, trends, and source contributions of CH₄ emissions are still highly uncertain, especially at an urban scale. Here, we present an observing system simulation experiment framework to quantitatively evaluate a potential measurement network that combines column and surface observations for estimating urban CH₄ emissions. We evaluate the observing systems from multiple perspectives, focusing on their ability to estimate monthly and interannual variability, and to attribute emissions to specific sectors. A multivariate linear regression analysis was performed to identify the sources of uncertainties in the posterior fluxes. A 10% annual rise in CH₄ emissions from 2021 to 2023 was assumed to evaluate the capability of the observing system to capture interannual variability and trends. We found that MUCCnet, the world's first permanent urban ground-based column greenhouse gas network with 5 stations, was able to capture the monthly and interannual variability and trends of CH₄ emissions. The significant uncertainties in emission estimates from MUCCnet-only inversions can be attributed to strong emissions from the Agriculture sector, which are far from the network deployment sites, or to limited observation coverage due to meteorological conditions. Surface in situ observations within the joint network can effectively reduce these uncertainties. The uncertainties in total CH₄ emission estimates can be reduced by using observations from MUCCnet and a surface in situ network, leveraging the complementarity between the two platforms. Using the joint network configuration, the interannual variability and trend of CH₄ emissions can be detected with low uncertainties.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 19","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JD043939","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145224303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Factors Contributing to the Unusually Low Antarctic Springtime Ozone in 2020–2023","authors":"Krzysztof Wargan,&nbsp;Gloria L. Manney,&nbsp;Nathaniel J. Livesey","doi":"10.1029/2025JD043621","DOIUrl":"https://doi.org/10.1029/2025JD043621","url":null,"abstract":"<p>The 2020–2023 Antarctic spring seasons saw large ozone holes, substantial ozone mass deficit, and low polar cap total ozone compared to the second decade of the 21st century, prompting questions about the pace of ozone recovery over Antarctica. We use a stratospheric composition reanalysis developed at the NASA Global Modeling and Assimilation Office and chemical ozone loss estimates derived from NASA's Aura Microwave Limb Sounder observations to identify the key factors contributing to these unusually large ozone holes. We find that the below-average Antarctic total column ozone and large ozone holes in each of the years of interest resulted from a different combination of the following: anomalously low ozone within the stratospheric polar vortex, strong chemical ozone depletion, weak dynamical ozone resupply, and the size and geometry of the polar vortex. We also interpret our findings in the broader context of ozone recovery, with a particular focus on September, the month when signs of recovery are most evident. We find no evidence challenging the current consensus that springtime Antarctic ozone is recovering in response to the implementation of the Montreal Protocol and its amendments.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 19","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145146694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Turbulent Exchange of \u0000 \u0000 \u0000 \u0000 CO\u0000 2\u0000 \u0000 \u0000 ${text{CO}}_{2}$\u0000 in the Lower Tropical Troposphere Across Clear-to-Cloudy Conditions","authors":"V. S. de Feiter,&nbsp;M. Janssens,&nbsp;S. E. M. de Haas,&nbsp;O. K. Hartogensis,&nbsp;C. Q. Dias-Junior,&nbsp;H. van Asperen,&nbsp;G. Martins,&nbsp;J. B. Miller,&nbsp;J. Vilà-Guerau de Arellano","doi":"10.1029/2025JD044231","DOIUrl":"https://doi.org/10.1029/2025JD044231","url":null,"abstract":"&lt;p&gt;This study investigates the roles of clear air entrainment and shallow cloud ventilation, alongside rainforest &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mtext&gt;CO&lt;/mtext&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${text{CO}}_{2}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;-assimilation, in the turbulent exchange of &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mtext&gt;CO&lt;/mtext&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${text{CO}}_{2}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; within the lower tropical troposphere under clear-to-cloudy conditions. Constrained by comprehensive observations from the CloudRoots-Amazon22 campaign, spanning leaf stomatal to upper atmosphere, we design and evaluate a representative shallow convective numerical experiment with the turbulence-resolving Dutch Atmospheric Large Eddy Simulation model, incorporating a bulk rainforest representation. We assess contributions from the rainforest, clouds, and environment through the vertically integrated, domain-averaged &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mtext&gt;CO&lt;/mtext&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${text{CO}}_{2}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; budget by comparing simulations with and without the dynamic effects of clouds. Our findings reveal three distinct diurnal regimes named: entrainment-diluting, cloud-ventilation-and-entrainment, and &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mtext&gt;CO&lt;/mtext&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${text{CO}}_{2}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;-assimilation. Shallow convective clouds (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;∼&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${sim} $&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;23%), clear air entrainment (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;∼&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${sim} $&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;21%), and rainforest &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mtext&gt;CO&lt;/mtext&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${text{CO}}_{2}$&lt;/anno","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 19","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JD044231","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145146455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Air Quality Field Measurements in Las Vegas: Ozone Formation and Its Sensitivity to NOx and VOCs","authors":"C. Warneke,&nbsp;C. E. Stockwell,&nbsp;J. Peischl,&nbsp;J. B. Gilman,&nbsp;A. Lamplugh,&nbsp;L. Xu,&nbsp;K. Zuraski,&nbsp;S. S. Brown,&nbsp;S. Baidar,&nbsp;R. Marchbanks,&nbsp;W. A. Brewer,&nbsp;M. Li,&nbsp;B. McDonald,&nbsp;M. M. Coggon","doi":"10.1029/2025JD043787","DOIUrl":"https://doi.org/10.1029/2025JD043787","url":null,"abstract":"<p>Las Vegas, Nevada is an urban center in the southwest US where the population is rapidly growing. In Las Vegas, surrounded by the Mojave Desert, biogenic emissions are low, but anthropogenic emissions, especially along the Las Vegas Strip, are a large source of volatile organic compounds (VOC) and nitrogen oxides (NO + NO₂ = NO_x) from volatile chemical products, cooking, and fossil fuel usage. This makes Las Vegas an ideal place to study anthropogenic VOC emissions and oxidation in the absence of a strong biogenic signal. The urban air quality in Las Vegas was measured at a stationary site and with a mobile laboratory. Biogenic VOC influence, VOC enhancement ratios, and weekday-weekend effects were evaluated. An Eulerian box model was constructed to evaluate the chemical processes impacting air quality in Las Vegas. The model showed that the daily ozone (O₃) enhancement, taken as the maximum O₃ produced midday above background, was approximately 30 ppb. The O₃ sensitivities to VOCs and NO_x showed that reductions in both would reduce O₃ production. Reducing NO_x or VOCs by half would reduce O₃ by 10.5 and 11.5 ppb, respectively. Reducing both NO_x and VOCs together would decrease O₃ by 15 ppb. The O₃ contribution from biogenic VOCs was ∼3.5 ppb, which is about 10% of the total produced O₃. This differs from other regions of the US, such as New York or Los Angeles, where biogenic VOCs contribute significantly to urban ozone.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 19","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JD043787","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145146692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}