Journal of Geophysical Research: Atmospheres最新文献

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Atmospheric Response to Antarctic Coastal Polynyas 大气对南极海岸冰融的响应
IF 3.8 2区 地球科学
Journal of Geophysical Research: Atmospheres Pub Date : 2025-07-17 DOI: 10.1029/2025JD043319
M. Noel, S. Masson, C. Rousset
{"title":"Atmospheric Response to Antarctic Coastal Polynyas","authors":"M. Noel,&nbsp;S. Masson,&nbsp;C. Rousset","doi":"10.1029/2025JD043319","DOIUrl":"https://doi.org/10.1029/2025JD043319","url":null,"abstract":"<p>The lack of sea ice in Antarctic coastal polynyas enables strong ocean-to-atmosphere heat fluxes and intense sea-ice production. Although these features are primarily driven by intense offshore winds, their impact on local atmospheric conditions remains poorly understood. This study employs a high-resolution polar Weather Research and Forecasting model configuration over the Prydz Bay region, East Antarctica, home to two major coastal polynyas: Cape Darnley and Mackenzie Bay polynyas. Sensitivity experiments over three winters (2014–2016) comparing simulations with and without polynyas reveal a marked and spatially confined atmospheric response. Polynya openings induce substantial surface heat release (up to 700 W m<sup>−2</sup>), warming near-surface air by over 5 K and triggering convection and clouds. This results in a thickening of the atmospheric boundary layer and the development of stronger surface winds (up to 4 m s<sup>−1</sup>) that converge toward a low-pressure anomaly. A particular emphasis is placed on the mechanisms controlling wind anomalies, using a dedicated wind tendency analysis. This diagnosis highlights that the processes involved depend on location and altitude within the polynya region and involve a balance between vertical mixing, horizontal advection, and pressure gradient forces—vertical mixing acting as the initiating factor. This study provides a novel modeling framework used to isolate the atmospheric response to coastal polynyas, overcoming limitations of previous studies and coarse-resolution models. It offers new insights into the role of polynyas in modulating regional climate and improving understanding of the processes driving their dynamics.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 14","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JD043319","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144647377","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}
引用次数: 0
Turbulence of Tropical Cyclones: From Peristrophic to Zonostrophic 热带气旋的湍流:从转流到反流
IF 3.8 2区 地球科学
Journal of Geophysical Research: Atmospheres Pub Date : 2025-07-17 DOI: 10.1029/2024JD042733
Boris Galperin, Alexander K. Nickerson, Gregory P. King, Jun A. Zhang
{"title":"Turbulence of Tropical Cyclones: From Peristrophic to Zonostrophic","authors":"Boris Galperin,&nbsp;Alexander K. Nickerson,&nbsp;Gregory P. King,&nbsp;Jun A. Zhang","doi":"10.1029/2024JD042733","DOIUrl":"https://doi.org/10.1029/2024JD042733","url":null,"abstract":"&lt;p&gt;Cyclostrophic rotation in the core region of tropical cyclones (TCs) imprints a distinct signature upon their turbulence structure. Its intensity is characterized by the radius of maximum wind, &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;R&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;m&lt;/mi&gt;\u0000 &lt;mi&gt;w&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${R}_{mw}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, and the azimuthal wind velocity at that radius, &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;U&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;m&lt;/mi&gt;\u0000 &lt;mi&gt;a&lt;/mi&gt;\u0000 &lt;mi&gt;x&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${U}_{max}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;. The corresponding cyclostrophic Coriolis parameter, &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mover&gt;\u0000 &lt;mi&gt;f&lt;/mi&gt;\u0000 &lt;mo&gt;ˆ&lt;/mo&gt;\u0000 &lt;/mover&gt;\u0000 &lt;mo&gt;=&lt;/mo&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;U&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;m&lt;/mi&gt;\u0000 &lt;mi&gt;a&lt;/mi&gt;\u0000 &lt;mi&gt;x&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $widehat{f}=2{U}_{max}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;/&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;R&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;m&lt;/mi&gt;\u0000 &lt;mi&gt;w&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${R}_{mw}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, far exceeds its planetary counterpart, &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;f&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $f$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, for all storms; its impact increases with storm intensity. The vortex can be thought of as a system undergoing a superposition of planetary and cyclostrophic rotations represented by the effective Coriolis parameter, &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mover&gt;\u0000 &lt;mi&gt;f&lt;/mi&gt;\u0000 &lt;mo&gt;∼&lt;/mo&gt;\u0000 &lt;/mover&gt;\u0000 &lt;mo&gt;=&lt;/mo&gt;\u0000 &lt;mrow&gt;\u0000 ","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 14","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JD042733","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144647378","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}
引用次数: 0
Making Sense of Bifurcation Diagrams: A New Framework to Understand the Roles of Clouds and Bare Sea Ice for Waterbelt States 分岔图的意义:一个新的框架,以了解云和裸露的海冰在水道国家的作用
IF 3.8 2区 地球科学
Journal of Geophysical Research: Atmospheres Pub Date : 2025-07-17 DOI: 10.1029/2025JD043568
Johannes Hörner, Aiko Voigt
{"title":"Making Sense of Bifurcation Diagrams: A New Framework to Understand the Roles of Clouds and Bare Sea Ice for Waterbelt States","authors":"Johannes Hörner,&nbsp;Aiko Voigt","doi":"10.1029/2025JD043568","DOIUrl":"https://doi.org/10.1029/2025JD043568","url":null,"abstract":"<p>Earth has experienced several pan-glaciations in its history, often interpreted as hard Snowball Earth periods with global ice cover. Alternatively, waterbelt states with a narrow equatorial strip of ice-free ocean provide a compelling explanation for the survival of life during these extreme glaciations. In this study, we establish a framework to quantify three atmospheric factors that influence waterbelt states: the spatial extent of bare dark sea ice set by the pattern of surface precipitation and evaporation, cloud masking of the ice-albedo feedback, and cloud shortwave feedback. We first explore these factors in the Budyko-Sellers energy balance model, and then investigate them in simulations with three versions of the ICON global climate model. This allows us to relate differences in the waterbelt states between ICON versions to the three factors. A broader Hadley circulation shifts the boundary between snow-covered and bare sea ice poleward, leading to waterbelt states whose ice lines are at higher latitudes. Cloud masking always works in favor of stable waterbelt states by weakening the ice-albedo feedback. The role of the cloud shortwave feedback, in contrast, depends on the ICON version: in one version, increasing cloud condensate over the low-latitude open ocean destabilizes waterbelt states and creates an additional small hysteresis. In the other two versions, the cloud shortwave feedback is stabilizing. While our study does not answer which of the model versions is most realistic, it provides a quantitative framework for understanding the atmospheric mechanisms that govern the existence and hysteresis of waterbelt states.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 14","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JD043568","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144647685","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}
引用次数: 0
Evaluation of the Stratospheric Impacts of Stratospheric Aerosol Injection With Solar-Powered Lofting 平流层气溶胶注入对平流层影响的评价
IF 3.8 2区 地球科学
Journal of Geophysical Research: Atmospheres Pub Date : 2025-07-16 DOI: 10.1029/2024JD042813
Ye Lu, Cheng-Cheng Liu, Yifeng Peng, Karen H. Rosenlof, Jianchun Bian, Pengfei Yu
{"title":"Evaluation of the Stratospheric Impacts of Stratospheric Aerosol Injection With Solar-Powered Lofting","authors":"Ye Lu,&nbsp;Cheng-Cheng Liu,&nbsp;Yifeng Peng,&nbsp;Karen H. Rosenlof,&nbsp;Jianchun Bian,&nbsp;Pengfei Yu","doi":"10.1029/2024JD042813","DOIUrl":"https://doi.org/10.1029/2024JD042813","url":null,"abstract":"<p>Stratospheric aerosol injection (SAI) introduces aerosols or their precursors into the stratosphere, reflecting sunlight and mitigating global warming. However, delivering these materials to the stratosphere at the required altitudes (18–25 km) poses practical challenges. Here, we evaluate a novel delivery method called solar-powered lofting (SPL), inspired by self-lofting during extreme wildfires. SPL coinjects a small amount of black carbon (BC) with SO<sub>2</sub> at lower altitudes accessible to commercial aircraft (∼13 km), allowing the SO<sub>2</sub> to self-loft into the stratosphere. Using the Community Earth System Model, we compare SPL simulations with traditional SAI simulation that injects equivalent SO<sub>2</sub> mass at 20 km at the same locations, but without BC. SPL and SAI scenarios generate similar global aerosol optical depths and effective radiative forcing. BC induces an additional 1.5 K annual mean warming in the tropical stratosphere, raising stratospheric water vapor by 0.42 ppm. The coinjected BC accounts for 20% of the annual mean temperature and water vapor anomalies. Furthermore, the BC strengthens the polar vortex and enhances the Brewer-Dobson circulation. As a result of the changes in dynamics and chemistry, the coinjected BC results in a 5% increase in Antarctic ozone depletion in October. The SPL method at aircraft-accessible altitudes offers comparable cooling efficiency but requires careful evaluation of additional BC impacts.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 14","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144647329","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}
引用次数: 0
Automatic Signal Discrimination Using Machine Learning on the Data From the Central and Eastern European Infrasound Network 中欧和东欧次声网络数据的机器学习自动信号识别
IF 3.8 2区 地球科学
Journal of Geophysical Research: Atmospheres Pub Date : 2025-07-16 DOI: 10.1029/2025JD044047
Marcell Pásztor, Tereza Sindelarova, Daniela Ghica, Ulrike Mitterbauer, Oleksandr Liashchuk, Giorgio Lacanna, Maurizio Ripepe, István Bondár
{"title":"Automatic Signal Discrimination Using Machine Learning on the Data From the Central and Eastern European Infrasound Network","authors":"Marcell Pásztor,&nbsp;Tereza Sindelarova,&nbsp;Daniela Ghica,&nbsp;Ulrike Mitterbauer,&nbsp;Oleksandr Liashchuk,&nbsp;Giorgio Lacanna,&nbsp;Maurizio Ripepe,&nbsp;István Bondár","doi":"10.1029/2025JD044047","DOIUrl":"https://doi.org/10.1029/2025JD044047","url":null,"abstract":"<p>A labeled data set of 216,681 infrasound detections was compiled using data from the Central and Eastern European Infrasound Network (CEEIN). Detections associated with quarry blasts, thunderstorms, eruptions of the Etna volcano, industrial activity, and the war in Ukraine were categorized using ground truth information, such as seismic and lightning data. To establish benchmark performance, a random forest classifier and a convolutional neural network (CNN) were trained separately, achieving F1 scores of 0.8170 and 0.8248 on the test set, respectively. An ensemble model, combining both classifiers, outperformed them achieving an F1 score of 0.8773. The model, initially trained on four CEEIN arrays, was tested on data from a separate station not included in training. Although performance initially declined, transfer learning and fine-tuning of the CNN and retraining the random forest model improved the ensemble model's F1 score to 0.9056 making it a considerable step. These results represent significant progress in automatic infrasound signal classification for monitoring the atmosphere.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 14","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JD044047","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144647328","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}
引用次数: 0
A Subsequent-Stroke Stepped Leader Repeatedly Colliding With the Remnants of the Preceding Stroke at Different Altitudes 在不同的高度上,后继一笔的阶梯式先导与前一笔的残余物反复碰撞
IF 3.8 2区 地球科学
Journal of Geophysical Research: Atmospheres Pub Date : 2025-07-16 DOI: 10.1029/2024JD043256
Z. Ding, V. A. Rakov, L. Musante, S. Chen, Y. Zhu, I. Kereszy
{"title":"A Subsequent-Stroke Stepped Leader Repeatedly Colliding With the Remnants of the Preceding Stroke at Different Altitudes","authors":"Z. Ding,&nbsp;V. A. Rakov,&nbsp;L. Musante,&nbsp;S. Chen,&nbsp;Y. Zhu,&nbsp;I. Kereszy","doi":"10.1029/2024JD043256","DOIUrl":"https://doi.org/10.1029/2024JD043256","url":null,"abstract":"<p>In a three-stroke negative cloud-to-ground flash, the leader of Stroke 2, while forming a new, heavily branched path to ground, briefly collided with the defunct (nonluminous) channel/branches of Stroke 1 at heights of about 2.0, 1.6, again 2.0 km, and 90 m above ground level. Each of the first three (higher-altitude) collisions was associated with luminosity waves originating from the collision point, including an upward reflection-type wave along the colliding leader channel and one or more transmitted waves along the residual branches of the preceding stroke. Based on the estimated extension speeds and RF field signatures, we attributed the transmitted luminosity waves to dart-stepped leaders developing in shorter segments of the decayed channel. As a result of the last collision, at a height of 90 m above ground level, a branch of the Stroke 2 leader entered the lower part of the residual (nonluminous) Stroke 1 channel and connected to the ground, producing a return stroke. Additionally, the heavily branched Stroke 2 leader created a ground termination about 950 m away from its ground termination common with Stroke 1. We observed four X-ray pulses of unknown origin with peaks ranging from 130 to 750 keV during a 3.5-ms or so interval around the time of the higher-altitude collisions during the leader stage of Stroke 2, but no detectable X-ray pulses during the leader stages of Strokes 1 and 3. The observed occurrence of X-ray pulses is unlikely to be random and appears to be linked to the Stroke 2 leader.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 14","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144647330","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}
引用次数: 0
Revealing Key Dynamical Mechanisms of a Severe Supercell Within a QLCS Using Rapid Update 4DVar Assimilation of C-Band Phased Array Weather Radar Data 利用c波段相控阵天气雷达数据快速更新4DVar同化揭示QLCS中严重超级单体的关键动力机制
IF 3.8 2区 地球科学
Journal of Geophysical Research: Atmospheres Pub Date : 2025-07-15 DOI: 10.1029/2024JD042762
Ruiting Liu, Jingya Wu, Mingxuan Chen, Rui Qin, Xian Xiao, Siteng Li, Lu Yang, Jianli Ma, Hongbo Zhang, Hao Huang, Lina Zhang
{"title":"Revealing Key Dynamical Mechanisms of a Severe Supercell Within a QLCS Using Rapid Update 4DVar Assimilation of C-Band Phased Array Weather Radar Data","authors":"Ruiting Liu,&nbsp;Jingya Wu,&nbsp;Mingxuan Chen,&nbsp;Rui Qin,&nbsp;Xian Xiao,&nbsp;Siteng Li,&nbsp;Lu Yang,&nbsp;Jianli Ma,&nbsp;Hongbo Zhang,&nbsp;Hao Huang,&nbsp;Lina Zhang","doi":"10.1029/2024JD042762","DOIUrl":"https://doi.org/10.1029/2024JD042762","url":null,"abstract":"<p>We investigate the evolution of a supercell storm within a quasi-linear convective system (QLCS) that occurred in the Beijing area on 12 June 2022. Using high spatiotemporal resolution observations from a C-band phased array radar (PAR), assimilated into a four-dimensional variational data assimilation system, we primarily analyze dynamical processes contributing to the development of the supercell storm and its associated mesocyclone. Our study shows that just before the convective cell is triggered, a significant convergence zone develops to the west of the terrain, forming several meso-γ vortices near the surface. During the merger of the convective cell and the QLCS from upper to lower levels, a strong downdraft generated by the QLCS enhances low-level horizontal convergence, further producing a stretching effect on the vortices within the storm and significantly increasing vertical vorticity. With the formation of the mesocyclone in the mature stage of supercell storm, the height of the rotational center rises to 4.5 km, and the maximum rotational velocity reaches 20 m/s. Our results indicate that the surface convergence lines and the meso-γ vortices along them strengthen low-level convergence and generate strong updrafts, triggering the initial storm. These intense updrafts transform horizontal vorticity into vertical vorticity and transport it upward. Additionally, the process of convective merging leads to strengthen low-level horizontal convergence, which forcibly stretches the mesovortex, enhancing vertical vorticity and allowing the convective storm to develop in a strong, organized manner and form the supercell storm.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 14","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JD042762","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144635372","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}
引用次数: 0
The Impact of the Bay of Bengal Sea Surface Temperature Gradient on Indian Summer Monsoon Rainfall 孟加拉湾海面温度梯度对印度夏季风降水的影响
IF 3.8 2区 地球科学
Journal of Geophysical Research: Atmospheres Pub Date : 2025-07-15 DOI: 10.1029/2025JD043655
Qucheng Chu, Shu Gui, Ruowen Yang, Meiyi Hou, Guolin Feng
{"title":"The Impact of the Bay of Bengal Sea Surface Temperature Gradient on Indian Summer Monsoon Rainfall","authors":"Qucheng Chu,&nbsp;Shu Gui,&nbsp;Ruowen Yang,&nbsp;Meiyi Hou,&nbsp;Guolin Feng","doi":"10.1029/2025JD043655","DOIUrl":"https://doi.org/10.1029/2025JD043655","url":null,"abstract":"<p>Indian summer monsoon rainfall (ISMR), which occurs between June and September, holds a pivotal role in both the agriculture and economy of the Indian subcontinent and the Greater Mekong Subregion (GMS). Our findings suggest that the combined influence of local SST warming and Indian Ocean Dipole (IOD) events can account for a substantial portion of historical meridional SST gradients (SSTG) in the Bay of Bengal (BOB), and thus contribute to the ISMR anomalies over Central India, Northeast India, and the northwestern GMS. The meridional SSTG in the BOB exert oceanic feedback on the atmosphere by modulating anomalous planetary boundary layer winds via the sea level pressure adjustment mechanism, vertical momentum mixing mechanism, and the thermal wind mechanism. The evolution of deep convection aligns with that of the meridional SSTG, thereby intensifying the downward transport occurred over the BOB north of 15°N and the upward transport occurred over the near-equator BOB. Both the temperature and pressure anomalies contribute to the anomalous easterlies at 850 and 500 hPa, and thus leads to the significant weakening of the Indian summer monsoon (ISM). Numerical experiments provide robust evidence supporting the proposed modulating influence of the meridional SSTG on the reduction of ISM rainfall over the BOB. The results highlight the combined impacts of local SST warming and IOD events.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 14","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144635162","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}
引用次数: 0
Regional and Temporal Variability of Atmospheric River Seasonality: Influences of Detection Algorithms and Moisture Transport Dynamics 大气河流季节性的区域和时间变化:探测算法和水汽输送动力学的影响
IF 3.8 2区 地球科学
Journal of Geophysical Research: Atmospheres Pub Date : 2025-07-15 DOI: 10.1029/2024JD043032
Diya Kamnani, Travis A. O’Brien, Samuel Smith, Paul W. Staten, Christine A. Shields
{"title":"Regional and Temporal Variability of Atmospheric River Seasonality: Influences of Detection Algorithms and Moisture Transport Dynamics","authors":"Diya Kamnani,&nbsp;Travis A. O’Brien,&nbsp;Samuel Smith,&nbsp;Paul W. Staten,&nbsp;Christine A. Shields","doi":"10.1029/2024JD043032","DOIUrl":"https://doi.org/10.1029/2024JD043032","url":null,"abstract":"<p>Understanding the regional and temporal variability of atmospheric river (AR) seasonality is crucial for preparedness and mitigation of extreme events. While ARs were thought to peak in winter, recent research shows they exhibit region-specific seasonality and are heavily influenced by the chosen detection algorithm. This study examines the link between the year-to-year consistency of peak-AR activity to the presence of a dominant seasonal pattern, considering both location and algorithm choice. Regions are categorized by their temporal characteristics: consistent patterns (e.g., East Asia), patterns with occasional outliers (e.g., British Columbia coast), and regions lacking a clear dominant peak season (e.g., South Atlantic, parts of Australia). Hence, not all regions display a consistent seasonal cycle of AR activity. This study quantifies the extent to which a region experiences a dominant peak season of AR activity (or lacks one) and offers insights to enhance decision-making in water management, natural hazard preparedness, and forecasting. Furthermore, given our finding that detection algorithms influence the peak season of AR activity, we also examine two diagnostic variables representative of moisture transport to corroborate our results. Integrated vapor transport, which captures meridional and zonal moisture transport, and Moist Wave Activity, representing moisture intrusions from lower to higher latitudes, are examined. Our analysis indicates that inconsistencies in the seasonal cycle of AR activity are not solely due to discrepancies in detection algorithms but also arise from changes in moisture transport.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 14","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JD043032","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144635163","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}
引用次数: 0
The Effect of Westerly Wind Bursts on ENSO Diversity: An Oceanic Perspective 西风爆发对ENSO多样性的影响:一个海洋视角
IF 3.8 2区 地球科学
Journal of Geophysical Research: Atmospheres Pub Date : 2025-07-15 DOI: 10.1029/2025JD043770
Yunhao Shi, Yanluan Lin
{"title":"The Effect of Westerly Wind Bursts on ENSO Diversity: An Oceanic Perspective","authors":"Yunhao Shi,&nbsp;Yanluan Lin","doi":"10.1029/2025JD043770","DOIUrl":"https://doi.org/10.1029/2025JD043770","url":null,"abstract":"<p>The relationship between westerly wind bursts (WWBs) and the El Niño-Southern Oscillation (ENSO) diversity has drawn widespread attention. However, the effect of WWBs on the oceanic intraseasonal Kelvin waves in the context of ENSO diversity formation remains largely unexplored owing to limited observational data and theoretical analysis. To explore ENSO diversity mechanisms, we employ a combination of 20–90–day bandpass filtering, complex empirical orthogonal function analysis and composite analysis to investigate to what extent the oceanic Kelvin waves are influenced by WWBs. From filtered sea level anomalies in the equatorial Pacific Ocean (150°E−100°W, 2°S–2°N) between 1993 and 2023, we identified 149 downwelling and 119 upwelling Kelvin waves. During eastern-Pacific (EP) El Niño years, the WWBs have a further east active center, stronger intensity, a larger zonal extent and longer duration compared to central-Pacific (CP) El Niño years. Similarly, Kelvin waves have stronger intensity, broader extension, and zonal distribution along the equator in EP El Niño years than in CP El Niño years. Statistical and composite analysis reveal a consistent relationship between the zonal range, center location, duration, strength of WWBs and the corresponding response of Kelvin waves (center location, speed, duration, amplitude) across CP and EP El Niño years. The finding implies that WWBs may act as a precursor to ENSO diversity from an oceanic perspective, playing a key role in both the theoretical framework and prediction of ENSO diversity.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 14","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144635164","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}
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