Journal of Geophysical Research: Atmospheres最新文献

{"title":"Quantifying Remote Source Contributions and Radiative Forcing of Airborne Dust Over East Asia With CALIPSO Observations","authors":"Jingyi Tang,&nbsp;Tianhe Wang,&nbsp;Ying Han,&nbsp;Jingtao Li,&nbsp;Ruiqi Tan,&nbsp;Sichen Wang,&nbsp;Ali Mamtimin,&nbsp;Fan Yang,&nbsp;Chenglong Zhou,&nbsp;Bakhriddin E. Nishonov,&nbsp;Mansur O. Amonov,&nbsp;Sabur F. Abdullaev","doi":"10.1029/2025JD046175","DOIUrl":"https://doi.org/10.1029/2025JD046175","url":null,"abstract":"<p>A thorough understanding of the sources, contributions, and transport pathways of airborne dust over East Asia is essential for evaluating its regional climatic and environmental impacts. Although widely used, numerical models yield uncertain dust loading estimates in receptor regions due to uncertainties in emission and deposition parameterizations. This study combines Cloud-Aerosol LiDAR and Infrared Pathfinder Satellite Observations data with a dust activity-constrained source-tracing algorithm to investigate dust sources over East Asia, and assesses associated radiative forcing using a radiative transfer model. Airborne dust over East Asia originates from multiple Northern Hemisphere sources. Based on dust occurrence frequency, the dominant contributor is the Gobi Desert (GD, ∼30%), followed by the Taklimakan Desert (TD, 8%–16%), Western Central Asia (WCA, ∼10%), and West Asia-South Asia/Middle East-North Africa sources (WA-SA/ME-NA, 5%–8% in southern East Asia). Contributions from remote sources exhibit marked vertical heterogeneity: GD dust accounts for over 50% of dust extinction below 5 km in northern East Asia and below 2.5 km in southern East Asia, whereas other sources contribute 5%–37% above these respective altitudes. Transport heights increase with source distance, ranging from 2–4 km for GD to 5–7 km for WA-SA and ME-NA clusters. Mean annual cumulative net radiative forcing transitions from cooling below 5 km to warming above, with GD contributing a peak cooling of −5,775 W m⁻² near 1.5 km over North China and distant sources contributing 13–36 W m⁻² of upper-tropospheric warming over southeastern China. These results provide a foundation for evaluating source-specific dust impacts on East Asian climate and air quality.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"131 17","pages":""},"PeriodicalIF":3.8,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148823378","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":"Unraveling the Drivers of Airborne Pollen Variability in a Rapidly Urbanizing Region: Interactions Between Land-Use Change and Meteorological Factors in Nanjing, Eastern China","authors":"Z. J. She,&nbsp;C. M. Ma,&nbsp;Z. Li,&nbsp;Y. M. Fang,&nbsp;F. Li,&nbsp;Y. C. Zhang,&nbsp;H. Y. Lu,&nbsp;Y. C. Li,&nbsp;A. J. Ding","doi":"10.1029/2025JD045928","DOIUrl":"https://doi.org/10.1029/2025JD045928","url":null,"abstract":"<p>Airborne pollen is a sensitive biological indicator of interactions between meteorological processes and land cover. Prior research has emphasized meteorological influences, with less focus on long-term land-cover changes. Using a 7-year data set (2013–2019) from rapidly urbanizing Nanjing, a city in eastern China, this study quantified pollen source areas, examined pollen-meteorology relationships from deseasonalized daily anomalies, and explored the relationships among airborne pollen, meteorology, and land cover. Results show that local airborne pollen primarily originates from within 5–20 km. At the synoptic scale, relative humidity was a consistent negative driver, wind speed a positive driver, and temperature a weak driver; precipitation showed taxon-specific correlations, which may be attributable to certain synoptic weather systems that concurrently favor both precipitation and pollen activity. Critically, the marked post-2015 decline in <i>Morus</i> and Poaceae pollen was robustly attributed to local agricultural-to-urban conversion (e.g., mulberry field loss explained 99.6% of <i>Morus</i> pollen variance). Given the absence of significant background climatic trends, the observed shifts in pollen concentration and seasonality are best explained by land-cover and land-management changes. This study demonstrates that in regions undergoing intense anthropogenic change, land- cover alterations can outweigh the influence of meteorological factors on pollen concentrations. Consequently, these results highlight airborne pollen as a valuable proxy for tracking human-driven environmental change.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"131 17","pages":""},"PeriodicalIF":3.8,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148849333","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":"Simulated Response of Extreme Moisture Transport to Nuclear Conflict","authors":"Chen Zhang,&nbsp;Andrew C. Winters,&nbsp;Joshua Coupe,&nbsp;Owen B. Toon","doi":"10.1029/2026JD047632","DOIUrl":"https://doi.org/10.1029/2026JD047632","url":null,"abstract":"<p>Nuclear war has the potential to cause global catastrophe, as soot from widespread fires blocks sunlight, triggers abrupt cooling, and collapses agriculture. This study examines the long-term response of weather and climate patterns to nuclear conflict, simulated by injecting ∼150 million tons of smoke into the stratosphere within the Community Earth System Model. An algorithm detecting extreme moisture transport events is applied to evaluate global hydrological impacts. The simulations reveal widespread declines in event frequency, particularly during each hemisphere's summer, but also narrow ocean-to-continent corridors of sharp frequency increases during the cold season, including across the North Pacific to the U.S. West Coast, the eastern North Atlantic to North Africa and extending eastward toward South and Southeast Asia, the South Pacific to Chile, and the South Indian Ocean to Australia. In these regions, extreme moisture transport events make disproportionately large contributions to total precipitation. Changes in event distribution are largely driven by circulation changes following the smoke injection: subtropical jets contract equatorward, continental surface anticyclones intensify, and anomalously strengthened offshore cyclones establish anomalous coastal pressure gradients, favoring enhanced moisture transport toward coastal locations. Over southwest North America, these events feature a classic atmospheric river (AR)-like pattern during all seasons following the smoke injection, which contrasts with the control simulation where AR-like characteristics appear only during the cold season. This study offers novel insight into how nuclear conflict could profoundly disrupt the global hydrological cycle and extreme precipitation, with critical implications for regional water resources in a severely perturbed climate system.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"131 17","pages":""},"PeriodicalIF":3.8,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148849295","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":"Dust and Primary Biological Aerosol Particles (PBAP) Effects on Sea Breeze Systems Over Houston","authors":"Qiuyan Du,&nbsp;Yingxiao Zhang,&nbsp;Claire Pettersen,&nbsp;Derek J. Posselt,&nbsp;Mark A. Smalley,&nbsp;Allison L. Steiner","doi":"10.1029/2026JD047979","DOIUrl":"https://doi.org/10.1029/2026JD047979","url":null,"abstract":"<p>Sea-breeze-induced convection plays a critical role in coastal weather but remains challenging to simulate due to complex aerosol–cloud interactions. Although mineral dust and primary biological aerosol particles (PBAPs) are known to act as cloud condensation nuclei and ice nucleating particles, their impacts on different convective cloud regimes and various cloud development stages are poorly understood. Here we examine the combined and individual impacts of dust and PBAPs on a representative convective case over Houston during the tracking aerosol convection interactions experiment campaign (17 June 2022) using WRF-Chem with explicit emissions and rupture processes of PBAPs, and aerosol-aware two-moment microphysics. The results show that dust and PBAPs generally reduce precipitation through decreases in rain production and ice-phase particle formation and growth, whereas ruptured PBAPs enhance liquid and ice water contents and increase precipitation efficiency. These microphysical responses become more evident with convective strength and are most pronounced in deep convection. Aerosol effects on convective development are expressed mainly through changes in the probability of moderate-to-deep transition, with dust and PBAPs increasing this transition and ruptured PBAPs reducing it. These findings suggest the stage-dependent impacts of natural aerosol on sea-breeze convection and underscore the importance of representing biological aerosol processes in weather and climate models.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"131 17","pages":""},"PeriodicalIF":3.8,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JD047979","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148849283","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":"Relationship Between the Global Distribution of Double Tropopause From Radio Occultation Data and Climate Indices","authors":"A. de la Torre,&nbsp;P. Alexander,&nbsp;T. Schmidt,&nbsp;A. K. Steiner,&nbsp;F. Ladstädter,&nbsp;R. Hierro","doi":"10.1029/2026JD046399","DOIUrl":"https://doi.org/10.1029/2026JD046399","url":null,"abstract":"<p>Double tropopauses (DTs) are a key but underutilized diagnostic of upper troposphere–lower stratosphere (UTLS) dynamics and stratosphere–troposphere exchange. Here we provide a global, observation-based assessment of DT variability and its coupling to large-scale climate modes using 14 years (2007–2020) of Radio Occultation Global Navigation Satellite System (RO-GNSS) temperature profiles. DT occurrence is quantified as the relative frequency of double to single tropopauses following the World Meteorological Organization lapse-rate definition. The global DT distribution exhibits robust midlatitude maxima and pronounced hemispheric asymmetries, including persistent enhancement over South America. A clustering framework reveals spatially coherent regimes of DT variability, highlighting stronger heterogeneity in the Northern Hemisphere and organized latitudinal structures linked to large-scale circulation boundaries. We then establish a systematic framework to diagnose DT–climate relationships by combining linear correlation (accounting for temporal autocorrelation) with nonlinear dependence via normalized mutual information (NMI), including lead–lag analysis within ±12 months. DT variability shows statistically significant, spatially coherent associations with multiple climate indices, including ENSO- and annular-mode variability. These relationships frequently organize into contiguous regions with consistent lags, indicating physically meaningful teleconnections. Near-zero lags reflect rapid atmospheric adjustment, while positive and negative lags point to delayed responses and potential precursor behavior, respectively. Nonlinear dependencies reveal regime-dependent dynamics that are not captured by linear metrics alone. Our results identify DTs as a sensitive, globally consistent tracer of UTLS dynamical variability and demonstrate their potential to provide new constraints on atmosphere–ocean coupling and predictive diagnostics of climate variability.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"131 17","pages":""},"PeriodicalIF":3.8,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148849280","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":"Spaceborne Far-Infrared Signal Simulations Over the Antarctic Plateau With Temperature-Dependent Ice Cloud Optical Properties","authors":"Tong Ren,&nbsp;Ping Yang,&nbsp;Xianglei Huang","doi":"10.1029/2025JD045957","DOIUrl":"https://doi.org/10.1029/2025JD045957","url":null,"abstract":"<p>Longwave cloud radiative effects significantly influence variability in global and regional Earth systems. However, there have been very few, if any, measurements of the far-infrared (FIR) radiation over the polar regions, where about half of the outgoing longwave radiation is in the FIR spectrum. This motivated the Polar Radiant Energy in the Far Infrared Experiment (PREFIRE) and was part of the motivation for the Far-infrared-Outgoing-Radiation Understanding and Monitoring (FORUM) mission. The absorption properties of ice in the FIR varies with temperature and should be considered when prescribing the radiative properties of ice particles. This study tests the ability of recently developed temperature-dependent aggregate and column ice particle optical models to represent the radiative signatures of ice clouds in the FIR, and their potential to support applications of PREFIRE and FORUM observations. Using a radiative transfer code, these models are used to simulate Thermal InfraRed Spectrometer (TIRS) measurements from the two PREFIRE CubeSats for all overpasses at the Concordia (DOME-C) station in January 2025, a polar day month when shortwave passive cloud retrievals are most accurate. The Clouds and Earth's Radiant Energy System (CERES) SYN1deg Level 3 hourly cloud retrievals are used as cloud inputs in the radiative transfer simulations. Temperature and humidity vertical profiles are taken from radiosonde data. The results show that both the aggregate and column ice optical models simulate the TIRS signals to within a brightness temperature of 4 K.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"131 17","pages":""},"PeriodicalIF":3.8,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JD045957","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148849297","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":"More Frequent and Enhanced Extreme Events of Air–Sea CO2 Fluxes","authors":"Yangyan Cheng,&nbsp;Bo Han,&nbsp;Jerry Tjiputra,&nbsp;Hao Luo,&nbsp;Qinghua Yang,&nbsp;Min Zhang,&nbsp;Dake Chen,&nbsp;Chao Min","doi":"10.1029/2025JD044933","DOIUrl":"https://doi.org/10.1029/2025JD044933","url":null,"abstract":"<p>The ocean is a crucial sink for anthropogenic CO₂ and experiences various biogeochemical extremes, yet it is not clear whether and to what extent such extreme events occur in air–sea CO₂ fluxes. Here, we established a framework to define oceanic carbon uptake extremes (CUXs) and release extremes (CRXs) using daily air–sea CO₂ flux from both an observational-based product and a state-of-the-art Earth system model. Globally, cumulative CUX and CRX intensity over 1982–2022 were −0.14 and 0.14 Pg C yr⁻¹, respectively, each accounting for ∼10% of the total oceanic CO₂ uptake. The number of annual days and the absolute mean intensity of CUXs (CRXs) increase at rates of 1.22 d dec⁻¹ (2.23 d dec⁻¹) and 0.08 mol C m² yr⁻¹ dec⁻¹ for both events. Under the high-warming future scenario, these increasing trends are projected to accelerate, leading to a nearly five-fold rise in the global cumulative intensity of CUXs and CRXs compared to the past four decades. After the 2050s, CRXs increase more rapidly than CUXs, especially in the Southern Ocean and North Atlantic, due to a reduced oceanic buffering capacity. Thermally driven seawater pCO₂ dominates over half of the projected global CUX and CRX days, primarily in temperate oceans. The model also indicates shifts from nonthermal to thermal dominance in the tropical Pacific and Atlantic, the Indian Ocean, and the sporadic high-latitude Southern Ocean, while the North Atlantic shows an opposite pattern. Our study shows that more frequent CRXs would further exacerbate the projected weakening in ocean carbon sinks.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"131 16","pages":""},"PeriodicalIF":3.8,"publicationDate":"2026-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148848843","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":"Significant Latitude-Dependent Sensitivity of Cloud Vertical Distribution to Surface Temperature Anomalies","authors":"Weiyuan Zhang,&nbsp;Jiming Li,&nbsp;Sihang Xu,&nbsp;Yang Zhao,&nbsp;Qiudi Xu,&nbsp;Yang Wang,&nbsp;Bida Jian,&nbsp;Yuan Wang","doi":"10.1029/2026JD047613","DOIUrl":"https://doi.org/10.1029/2026JD047613","url":null,"abstract":"<p>Changes in the vertical distributions of cloud fraction (CF) and cloud phase (CP) are robust signatures of climate change and directly influence atmospheric heating rates, planetary energy budget and hydrological cycle. However, the global sensitivities of CF and CP profiles to surface temperature (ST) change remain poorly understood, contributing to major uncertainties in climate projections. Using DARDAR-MASK observations, we show that clouds in low latitudes exhibit predominantly negative sensitivities, largely associated with a weakened Walker circulation. In the subtropical to mid-latitude regions, low clouds decrease significantly with increasing STs. Over oceans, this reduction is associated with ST, estimated inversion strength, and horizontal ST advection, whereas over land, 850-hPa relative humidity (RH) accounts for ∼45.6% of the total sensitivity. In contrast, high clouds increase in mid-latitudes, mainly associated with enhanced upper-tropospheric relative humidity and intensified ascent. Land–sea contrast further contributes to hemispheric asymmetry in mid-latitude sensitivities. In polar regions, CF exhibits positive sensitivities with rising atmospheric RH. Regarding CP sensitivity, the ratios of ice clouds to all clouds exhibit positive sensitivities at mid-to-high latitudes but negative sensitivities at low latitudes within the mixed-phase temperature range (−40 to 0°C), reflecting the combined influences of dynamical conditions and ice-nucleating particles. These results provide an observation-based understanding of the sensitivity of global cloud vertical distribution to ST variations, with implications for radiative feedbacks and constraints on climate models.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"131 16","pages":""},"PeriodicalIF":3.8,"publicationDate":"2026-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148848728","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":"High-Resolution Regional Atmospheric Simulation of Precipitation and Isotopes in Central America","authors":"Yan Yang,&nbsp;Christian Birkel,&nbsp;Chris Soulsby,&nbsp;Ana M. Durán-Quesada,&nbsp;Ricardo Sánchez-Murillo,&nbsp;Germain Esquivel-Hernández,&nbsp;Kei Yoshimura,&nbsp;Dörthe Tetzlaff","doi":"10.1029/2026JD046723","DOIUrl":"https://doi.org/10.1029/2026JD046723","url":null,"abstract":"<p>With advances in global and regional circulation models, the high-resolution simulation of atmospheric variables has become increasingly feasible. In this study, we use IsoRSM, an isotope-enabled regional spectral model, to improve the simulation of precipitation and its isotopic composition over tropical Costa Rica, which is marked by a pronounced topography and is surrounded by two oceans. A 14-year (2010–2023) simulation was performed at a relatively high spatial (5 km) and temporal (6-hourly) resolution over a 6° × 6° domain covering Costa Rica and surrounding regions. Model outputs were evaluated using observations from 58 precipitation-amount sites and 27 isotope-monitoring sites and were compared with a 10 km IsoRSM simulation from a previous study over a larger spatial domain. After applying quantile mapping (QM) bias correction, the model generally captured the spatial patterns and seasonal cycles of precipitation inputs and precipitation isotopes across Costa Rica. The mean Kling-Gupta efficiency (KGE) for bias-corrected precipitation δ²H reached 0.43, and the 5 km simulation outperformed the previous 10 km run, highlighting the benefits of improved topographic representation. IsoRSM also clearly simulated the δ²H-δ¹⁸O relationship and the interannual variability along the topographical gradient of Costa Rica. Thus, the bias-corrected IsoRSM outputs offer a promising source of simulated data for further application, such as the forcing data for isotope-enabled eco-hydrological models.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"131 16","pages":""},"PeriodicalIF":3.8,"publicationDate":"2026-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JD046723","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148848729","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":"Statistical Evidence for Factors Associated With Positive Leader Branching in Long Air-Gap Discharges","authors":"Lili Guo,&nbsp;Xiangen Zhao,&nbsp;Xiankang Wang,&nbsp;Xiaopeng Liu,&nbsp;Yao Yao,&nbsp;Yaping Du,&nbsp;Junjia He","doi":"10.1029/2026JD046897","DOIUrl":"https://doi.org/10.1029/2026JD046897","url":null,"abstract":"<p>Branching is a common feature in positive leader development, which changes the channel topology and significantly influences discharge behavior. However, the factors associated with its occurrence remain poorly understood. In this study, an event-based analytical framework was established using synchronized optical observations and electrical measurements. Five physically motivated variables were constructed, including the injected charge <i>Q</i>, the rise rate of applied voltage <i>dU</i>/<i>dt</i>, the background field <i>E</i>, the background-field direction angle <i>θ</i>₁, and the prior-channel deflection angle <i>θ</i>₂. Their independent, nonlinear, and interaction effects were analyzed using multivariable logistic regression, restricted cubic splines, and random-forest-assisted interaction mining with regression validation. Primary and sensitivity analyses show that <i>Q</i>, <i>dU</i>/<i>dt</i>, and <i>E</i> are consistently and positively associated with branching occurrence, whereas <i>θ</i>₁ and <i>θ</i>₂ provide weaker and less stable information. <i>Q</i> shows the most reproducible nonlinear association, although its curve shape is partly affected by original-scale skewness. The interaction rule of <i>E</i> &gt; 275 kV/m and <i>dU</i>/<i>dt</i> &gt; 8.1 kV/μs is identified as the most reproducible candidate interaction signal, suggesting that branching is more likely when stronger background-field conditions coincide with faster <i>dU</i>/<i>dt</i>; however, its statistical support is sensitive to variable definition and sample composition. These results suggest that positive leader branching is associated with multiple interacting field-related factors rather than a single fixed threshold. The proposed event-based proxy-variable framework provides a feasible approach for quantitatively analyzing branching-related factors under the resolution limits of the present experiments.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"131 16","pages":""},"PeriodicalIF":3.8,"publicationDate":"2026-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JD046897","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148848771","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}