Journal of Geophysical Research: Atmospheres最新文献

{"title":"An Instrumental Method for the Simultaneous Determination of Organic Carbon, Elemental Carbon, Inorganic Nitrogen, and Organic Nitrogen in Aerosol Samples","authors":"Cong Cao,&nbsp;Xu Yu,&nbsp;Wing Hei Marco Wong,&nbsp;Ningning Sun,&nbsp;Kun Zhang,&nbsp;Zihan Sun,&nbsp;Luyao Chen,&nbsp;Can Wu,&nbsp;Gehui Wang,&nbsp;Jian Zhen Yu","doi":"10.1029/2025JD043904","DOIUrl":"https://doi.org/10.1029/2025JD043904","url":null,"abstract":"<p>Carbonaceous and nitrogenous materials are major components of atmospheric aerosols. Their measurements are fundamental for quantifying the crucial roles of aerosols in air quality, climate, ecosystems, and human health. We present the first instrumental method capable of simultaneous quantification of organic carbon (OC), elemental carbon (EC), inorganic nitrogen (IN), and organic nitrogen (ON) in aerosol samples. By integrating thermal evolution (TE) with multivariate curve resolution (MCR) data analysis, this method effectively resolves overlapping TE signals of OC, EC, IN, and ON, circumventing limitations of traditional analytical methods that lack MCR capabilities. Validation against established reference methods showed strong agreement across all components. In comparison with OC and IN, EC and ON exhibited greater variability due to their typical lower proportions in total carbon and total nitrogen, respectively, as well as inherent ambiguities in MCR analysis. The instrumental method was applied to 161 aerosol samples collected from six sites in China during the winter of 2023–2024. The average mass concentrations of IN, ON, OC, and EC were 10.5 ± 6.7, 2.4 ± 1.5, 14.1 ± 7.3, and 4.4 ± 3.2 μg/m³, respectively, with an atomic OC/ON ratio of 7.5 ± 1.9. This ratio, unavailable in past aerosol characterization studies, provides new insights into the validation of various biogenic and anthropogenic sources. Importantly, it can serve as a valuable constraint for atmospheric models, improving simulations of carbonaceous and nitrogenous aerosol sources and transformations. The ability to simultaneously quantify OC, EC, IN, and ON represents a significant advancement in aerosol characterization, offering a powerful new tool for atmospheric research.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 19","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145272012","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":"Total Column GHG Ratios From Ground-Based Measurements Inform Emissions Inventories","authors":"Aaron G. Meyer,&nbsp;Jonathan E. Franklin,&nbsp;Colin Harkins,&nbsp;Brian C. McDonald,&nbsp;John C. Lin","doi":"10.1029/2025JD044398","DOIUrl":"https://doi.org/10.1029/2025JD044398","url":null,"abstract":"&lt;p&gt;Accurately characterizing greenhouse gas (GHG) emissions is essential for improving inventories and evaluating mitigation efforts. However, this remains particularly challenging in urban environments with heterogeneous emissions and complex meteorological conditions. One effective approach which addresses these challenges uses trace gas ratios of atmospheric measurements to evaluate emissions. This study leverages total column concentration (&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;X&lt;/mi&gt;\u0000 &lt;mtext&gt;gas&lt;/mtext&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${X}_{text{gas}}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;) measurements from a single EM27/SUN spectrometer in Utah's Salt Lake Valley (SLV) to analyze &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;X&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;C&lt;/mi&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;H&lt;/mi&gt;\u0000 &lt;mn&gt;4&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mo&gt;:&lt;/mo&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;X&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;C&lt;/mi&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;O&lt;/mi&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${X}_{mathrm{C}{mathrm{H}}_{4}}:{X}_{mathrm{C}{mathrm{O}}_{2}}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&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;X&lt;/mi&gt;\u0000 &lt;mtext&gt;CO&lt;/mtext&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mo&gt;:&lt;/mo&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;X&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;C&lt;/mi&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;O&lt;/mi&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${X}_{text{CO}}:{X}_{mathrm{C}{mathrm{O}}_{2}}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; ratios across multiple spatiotemporal scales. By applying a rolling ratio method on sub-day time windows, we identify periods of strongly covarying concentration enhancements throughout the multi-year data set. This method reveals seasonal trends that are obscured using approaches from previous literature. We also examine how ratio variations correspond to changing wind conditions, facilitating more granular spatial emissio","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 19","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JD044398","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145271830","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":"High-Fidelity Experimental Simulations of Atmospheric Flow Near Low-Intensity Fires in a Wildland-Urban Interface","authors":"Dongqi Lin,&nbsp;Marwan Katurji,&nbsp;Peyman Zawar-Reza,&nbsp;Alena Malyarenko,&nbsp;Andres Valencia,&nbsp;Jiawei Zhang","doi":"10.1029/2025JD043641","DOIUrl":"https://doi.org/10.1029/2025JD043641","url":null,"abstract":"<p>With increased urbanization, fires in the wildland urban interface (WUI) have become a severe problem worldwide. The unique features of WUI may influence the atmospheric flows in the vicinity of fire. This study utilizes the parallelized large eddy simulation model (PALM) system for fire-atmosphere simulations of Bottle Lake Forest, Christchurch, New Zealand. Over 3,000 residential buildings are situated around the 7 <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mrow>\u0000 <mi>k</mi>\u0000 <mi>m</mi>\u0000 </mrow>\u0000 <mn>2</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${mathrm{k}mathrm{m}}^{2}$</annotation>\u0000 </semantics></math> forest, with many homes only 50 m away from the forest edge. We conducted high-fidelity fire-atmosphere simulations with the finest grid spacing of 4 m. Wildland forest (WF) and flat terrain simulations were conducted to provide a reference for comparison with WUI simulations. Fire-weather conditions for the 2022/2023 New Zealand fire season were selected based on the Fire Weather Index (FWI). Data from previous fire field campaigns were obtained to represent a low-intensity fire heat forcing. The results reveal a pulsing behavior in downwind heat transport when the forest canopy is included. Furthermore, the presence of the WUI is associated with extended downwind fire heat transport compared to WF and flat terrain scenarios. This study is the first to simulate atmospheric flows near fires in a WUI setting with such high fidelity. The findings highlight the critical role of WUI features in shaping fire-atmosphere dynamics, though further research is required to disentangle the contributions of individual WUI components to these effects.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 19","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JD043641","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145271916","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":"Observationally Constrained NOx-Catalyzed Ozone Production in the Upper Troposphere During the Asian Summer Monsoon","authors":"E. M. Waxman,&nbsp;R.-S. Gao,&nbsp;T. Thornberry,&nbsp;R. McLaughlin,&nbsp;G. Novak,&nbsp;E. Atlas,&nbsp;S. Schauffler,&nbsp;V. Treadaway,&nbsp;K. Smith,&nbsp;R. Lueb,&nbsp;R. Hendershot,&nbsp;T. Campos,&nbsp;G. Wolfe,&nbsp;J. M. St. Clair,&nbsp;E. Delaria,&nbsp;D. Anderson,&nbsp;S. Viciani,&nbsp;F. D’Amato,&nbsp;G. Bianchini,&nbsp;M. Barucci,&nbsp;C. Gurganus,&nbsp;L. Iraci,&nbsp;J. Podolske,&nbsp;G. Diskin,&nbsp;Y. Choi,&nbsp;J. DiGangi,&nbsp;T. P. Bui,&nbsp;J. Dean-Day,&nbsp;C. Gatebe,&nbsp;L. L. Pan,&nbsp;A. Rollins","doi":"10.1029/2024JD043218","DOIUrl":"https://doi.org/10.1029/2024JD043218","url":null,"abstract":"<p>Intense and frequent convection occurring during the Asian Summer Monsoon (ASM) rapidly transports surface emissions to the upper troposphere (UT). Depending on their chemical reactivities, pollutants transported to the UT via this mechanism may either undergo chemistry in the UT region or be transported into the lower stratosphere. The Asian Summer Monsoon Chemical and CLimate Impact Project (ACCLIP) used high-altitude research aircraft to characterize chemistry in the tropopause region within the ASM anticyclone and outflows of monsoon convection during summer 2022. Here, we use measurements of trace gases from ACCLIP and results from a 0-D model constrained by airborne observations to calculate net ozone production rates in airmasses influenced by recent convection and in the summer monsoon background upper troposphere/lower stratospheric air. We find that ozone production inside the polluted air downstream of recent convection is up to one order of magnitude higher than that in the cleaner background upper troposphere. The ozone production is driven by NO + HO₂ produced from CO and OVOC oxidation, rather than from organic peroxy radicals produced from volatile organic compounds inside the highly polluted airmasses. Consistent with previous modeling work, we find efficient HO_x (OH + HO₂) cycling is dominated by reactions with CO. Ozone production in this region is primarily NO_x-limited and increases with higher NO_x such as during convective events with lightning NO_x production. Further, we find that the dominant impact of enhanced NO_x here is through acceleration of HO_x cycling, and thus an increase in ozone production.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 19","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2024JD043218","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145271706","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":"Investigating the Characteristics and Dynamics of Convective Updrafts in Observed and Simulated Tropical Cyclone Rainbands","authors":"Nicholas R. Barron,&nbsp;Anthony C. Didlake Jr.,&nbsp;Yunji Zhang,&nbsp;Paul D. Reasor","doi":"10.1029/2024JD043152","DOIUrl":"https://doi.org/10.1029/2024JD043152","url":null,"abstract":"<p>This study uses the airborne Doppler radar data set, TC-RADAR, and model simulations from the Penn State Ensemble Kalman Filter data assimilation system to examine the dynamics and evolution of tropical cyclone (TC) rainband convective updrafts. This examination utilizes an updraft selection algorithm and statistical analysis of convective updraft characteristics previously developed based on observations of TC rainband convective updrafts. The selected updrafts are collectively analyzed by their spatial frequency, radius, azimuthal location (relative to the environmental 200–850 hPa wind shear and environmental 850 hPa mean flow), structural characteristics, and secondary circulation (radial/vertical) flow pattern. The observed updrafts compare favorably with the simulated updrafts. A wavenumber-1 asymmetry is found, showing that convective updrafts in the downshear quadrants of the TC are more frequent. The radial flow of updraft circulations aligns with the prevailing vortex-scale radial flow, which is governed by the environmental shear or low-level mean flow-induced asymmetry. Convective-scale circulations are hypothesized to be significantly influenced by vortex-scale radial flow at the updraft base and top altitudes. The bottom-up decay of aging convective updrafts, caused by increased low-level downdrafts, affects the base altitude and the subsequent radial flow of the updraft circulation. The findings presented in this study support previous literature regarding observed convective-scale patterns of organized rainband convection in a mature TC.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 19","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2024JD043152","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145224071","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":"Near-Source Ammonia (NH3) Fluxes and Evolution Observed From Airborne Measurements in Plumes Up To 25 km Downwind From Large Beef Cattle Facilities","authors":"Julieta F. Juncosa Calahorrano,&nbsp;Amy P. Sullivan,&nbsp;Ilana B. Pollack,&nbsp;Joseph Robert Roscioli,&nbsp;Dana R. Caulton,&nbsp;Megan E. McCabe,&nbsp;Kathryn M. Steinmann,&nbsp;En Li,&nbsp;Jeffrey R. Pierce,&nbsp;Lillian E. Naimie,&nbsp;Da Pan,&nbsp;Jeffrey L. Collett Jr.,&nbsp;Emily V. Fischer","doi":"10.1029/2024JD041559","DOIUrl":"https://doi.org/10.1029/2024JD041559","url":null,"abstract":"<p>The Transport and Transformation of Ammonia (TRANS²Am) campaign took place in northeastern Colorado in the summers of 2021 and 2022. One of the goals of TRANS²Am was to study the evolution of ammonia (NH₃) in plumes from large animal feeding operations. This work investigates the nearfield deposition of NH₃ in four plumes from large animal husbandry facilities observed during TRANS²Am using a mass balance approach with methane (CH₄) as a conservative tracer in the timescales of plume transport. Since the plumes in TRANS²Am were not sampled in a pseudo-Lagrangian manner, an empirical model is developed to correct for variations in summertime NH₃ emissions as a function of time of day. The mass balance approach results show that the average summertime NH₃ decay time to 80% and 60% against deposition in plumes from large animal sources is 43 (+11/−7) and 85 (+19/−14) min, respectively. Additionally, we present estimates of net fluxes every 5 km downwind of the plume. Under the hot, dry summertime midday conditions sampled during TRANS²Am, we found that within 10–15 km of the large emission sources studied, NH₃ undergoes net deposition. Beyond this distance, the complex environmental exchange of NH₃ between the atmosphere and the surface suggests that fresh NH₃ emissions from smaller nearby sources could switch the direction of the net flux to emission.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 19","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2024JD041559","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223791","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":"Unusual Mesospheric Zonal Wind Reversal Observed by the Wuhan MST Radar During the Winter 2015/2016","authors":"Weifan Zhang,&nbsp;Li Chang,&nbsp;Yusong Qin,&nbsp;Xun Lu,&nbsp;Chao Qiu","doi":"10.1029/2025JD044162","DOIUrl":"https://doi.org/10.1029/2025JD044162","url":null,"abstract":"<p>An unusual zonal wind reversal unrelated to Sudden Stratospheric Warming events in the mesosphere is detected by the Wuhan MST radar (29.51°N, 114.13°E) during the winter of 2015/2016. Interestingly, an upper stratosphere/lower mesosphere (USLM) disturbance is captured at the beginning of the wind reversal. We find this abnormal zonal wind reversal is related to the enhanced activity of PW2 in the mesosphere by using Modern-Era Retrospective Analysis for Research and Applications version 2 reanalysis data. Further diagnostic analysis suggests that the enhanced planetary waves (PWs) may have developed from the broken PWs during the USLM. Simultaneously, the mesosphere of 30°–40°N contains additional wave sources associated with the baroclinic/barotropic instability. These enhanced PWs eventually cause the wind reversal. Additionally, during the wind reversal, the radar is in the position of constant negative temperature gradient and colder region, favoring the continuation of the wind reversal.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 19","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223835","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":"Comparison of Cloud-Type Properties and Radiative Effect Decomposition in Tropical Convectively Active Regions Using CERES High-Resolution Data","authors":"Kuan-Man Xu,&nbsp;Moguo Sun,&nbsp;Yaping Zhou","doi":"10.1029/2025JD043853","DOIUrl":"https://doi.org/10.1029/2025JD043853","url":null,"abstract":"<p>Land and oceanic convection exhibit significant contrasts in intensity and entrainment, but their effects on the properties of other cloud types remain unclear. This study examines a 19-year mean of cloud properties and top-of-the-atmosphere (TOA) cloud radiative effects (CREs) by cloud type, with a focus on regional variations across convectively active tropical regions. Forty-two cloud types are classified based on effective cloud-top pressure and cloud optical depth. The analysis reveals distinct regional differences in cloud occurrence and properties, with oceanic regions dominated by convective anvils and boundary-layer clouds, which have higher liquid/ice water contents, while land regions feature higher fractions of mid-level clouds with lower liquid/ice water contents. The study further explores shortwave (SW), longwave (LW), and net CREs, decomposing the contributions of individual cloud types to total CRE differences between two regions into three components: CRE deviations within a cloud type, cloud fraction (CF) deviations, and their combined effect. Results show that CF deviations have the largest impact, enhancing LW warming and SW cooling for mid- and high-level clouds while reducing SW and net cooling for low-level clouds. Although the effects of CRE deviations are smaller than those of CF deviations for individual cloud types, its collective contribution to total regional CRE differences, particularly for net CRE, is more comparable, because the former exhibits consistent regional differences across all cloud types while the latter is influenced by opposing effects between low- and high-level clouds. The decomposition analysis also highlights significant regional variations driven by land-ocean contrasts and meteorological forcings.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 19","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JD043853","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223836","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":"Assessing Dynamic and Thermodynamic Variability in Initial and Boundary Conditions for Snowstorm Prediction in the Northeast United States","authors":"Brian C. Filipiak,&nbsp;Marina Astitha,&nbsp;Diego Cerrai","doi":"10.1029/2025JD044240","DOIUrl":"https://doi.org/10.1029/2025JD044240","url":null,"abstract":"<p>Winter storms present significant hazards across the Northeast United States, often disrupting daily life. Numerical modeling of these storms is an important component for understanding the physical processes that cause significant impacts and for predicting their effects ahead of time. Initial and boundary conditions are an essential component to limited-area modeling; variability in these conditions can significantly alter the simulations. While previous modeling studies have investigated sensitivities in model physics, there has been limited exploration of the impact of different initial condition sources; differences within these sources can include horizontal and vertical resolution, data assimilation schemes, and domain. This study aims at identifying the sources of variability from the initialized atmospheric fields within four different sets of initial conditions and their impact on the prediction of winter precipitation processes. The key finding was that relative humidity across different initial and boundary conditions produced the most uncertainty on the model simulation, while variability in temperature or synoptic conditions had a minor role. To explain the precipitation differences seen during the simulations, vertical profiles of relative humidity and temperature were connected to microphysical hydrometeor species tracked within the model. The findings suggested that relative humidity differences are heavily linked to precipitation accumulation discrepancies and were the main source of variability from the initial conditions. These results call for the development of more accurate relative humidity profiles for model initial and boundary conditions.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 19","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223837","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":"Waveguide Teleconnection Mechanisms Driving Summer Compound Heat-Humidity Extremes in China Land Monsoon Region","authors":"Jiayi Mu,&nbsp;Qianrong Ma,&nbsp;Shujuan Hu,&nbsp;Taichen Feng,&nbsp;Rui Hu,&nbsp;Pengcheng Yan,&nbsp;Guolin Feng","doi":"10.1029/2025JD043884","DOIUrl":"https://doi.org/10.1029/2025JD043884","url":null,"abstract":"<p>Escalating compound heat-humidity extremes (CHHEs) pose severe threats to socioeconomic stability and human health. Using the wet-bulb globe temperature, we reveal summer CHHEs exhibited consistently increasing trends across the China Land Monsoon (CLM) region during 1961–2022, significantly in the northeast and southwest. The 13-year sliding correlations indicate that since 2000, the British Okhotsk Corridor (BOC)-Silk Road Pattern (SRP) nexus shifted from a strong to weak state, which influenced CHHEs variability. During the weak BOC-SRP nexus period, an anomalous high-pressure system dominated northern China, especially northeastern CLM, and was intensified by negative potential vorticity anomalies through subsidence and diabatic heating. Simultaneously, abundant moisture transport from the western Pacific into northeastern CLM reinforced hot and humid conditions, jointly increasing CHHEs. Over southwestern CLM, the high-pressure system strengthened anomalous easterlies, which together with negative vorticity advection increased moisture divergence. Additionally, meridional temperature advection promoted warm air accumulation in the lower troposphere, further increasing CHHEs. Finally, the weak BOC-SRP nexus is modulated by North Atlantic tripole sea surface temperature anomalies by Rossby wave energy divergence, as confirmed by Community Earth System Model simulations. Overall, this study highlights the critical role of mid- to high-latitude teleconnections variable coupling states in regulating CHHEs in the CLM region.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 19","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145224069","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}