Atmospheric Research最新文献

{"title":"Altitude-resolved O3 transport in the Beijing-Tianjin-Hebei region: A multi-scenario analysis of extreme meteorology and pollution gradients","authors":"Hanyu Zhang ,&nbsp;Jungang Wang ,&nbsp;Maofa Ge ,&nbsp;Shengrui Tong ,&nbsp;Hailiang Zhang ,&nbsp;Zhiliang Yao","doi":"10.1016/j.atmosres.2025.108721","DOIUrl":"10.1016/j.atmosres.2025.108721","url":null,"abstract":"<div><div>Tropospheric ozone (O₃) pollution is an emerging challenge in the Beijing-Tianjin-Hebei region, where extreme meteorology and multiple pollution gradients frequently occurred. However, altitude-dependent structure of O₃ transport under such conditions has been rarely quantified. Here, we resolved horizontal and vertical O₃ fluxes in Beijing, Tianjin and Shijiazhuang across favorable/unfavorable meteorology, heatwaves, and varying pollution gradients through WRF-CAMx models. Results revealed strong spatial autocorrelation for O₃ across “2 + 36” Chinese cities (Moran's I: 0.21–0.77), with pronounced clustering in autumn and winter. Dominant southwest-northeast corridors were identified, with episodic cross-sea inflows to Tianjin, contributing 12.1 %–21.5 % of total inflow. Horizontal inflow and outflow fluxes peaked on pollution days (e.g., exceeding 44 kt/d in Beijing) and bottomed on excellent days (e.g., 28.8 kt/d in Beijing), while net fluxes showed the opposite trend, ranging from 0.4 to 5.3 kt/d. Vertically, upward fluxes maximized during pollution days, with Beijing transitioning from a net “sink” (−24.0 to −55.7 kt/d in non-pollution scenarios) to a “source” (46.7–85.5 kt/d on pollution days), whereas Tianjin and Shijiazhuang consistently acted as a “source”. Furthermore, the vertical distribution of the horizontal and vertical net fluxes showed significant differences across scenarios, and the altitude at which the maximum flux occurs also varied with scenarios. Severe pollution episode analysis demonstrated the altitude-dependent and city-specific interplay between transport and photochemistry in driving episodic O₃ extremes. These findings refine understanding of how altitude-scenario interactions shape O₃ dynamics, supporting the coordinated control strategies.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"332 ","pages":"Article 108721"},"PeriodicalIF":4.4,"publicationDate":"2025-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145796305","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":"Role of nonlinear convection–SST sensitivity in shaping the southward displacement of westerly anomalies during El Niño peak phase","authors":"Jingwen Sun ,&nbsp;Jianing Lu ,&nbsp;Yifan Jia ,&nbsp;Ruihuang Xie","doi":"10.1016/j.atmosres.2025.108712","DOIUrl":"10.1016/j.atmosres.2025.108712","url":null,"abstract":"<div><div>This study investigates the southward displacement of anomalous westerlies over the central equatorial Pacific during El Niño peak phase, using ERA5 reanalysis and long-term simulations from UKESM1.0-LL. The analysis reveals that this displacement is anchored by the seasonal migration of the tropical warm pool, thereby enhancing convection sensitivity to sea surface temperature (SST) south of the equator. The spatial structure and intensity of the westerly anomalies are further regulated by the nonlinear convection–SST relationship, with sensitivity peaking within the 27°–29 °C high SST range. Observation shows that, prior to 2000, stronger El Niño events produced more intense and spatially extensive southward-displaced westerly anomalies, whereas since the early 21st century, a La Niña–like mean-state change has weakened the convection–SST sensitivity and reduced the magnitude and extent of the westerly anomalies. Similar relationships among southward-displaced westerly anomalies, El Niño amplitude and convection-SST sensitivity were reproduced in UKESM1.0-LL model. Building on these findings, a synergistic framework is proposed, in which El Niño amplitude sets the scale of SST anomaly forcing, convection–SST sensitivity modulates the convective response, and the warm pool background constrains the spatial location of convection and associated wind anomalies. This thermodynamic mechanism complements existing dynamical explanations and highlights the role of convection–SST sensitivity in shaping El Niño-induced wind responses.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"332 ","pages":"Article 108712"},"PeriodicalIF":4.4,"publicationDate":"2025-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145785327","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":"Evidence of the linkage between mesoscale eddy activity in the Bay of Bengal and Indian Summer Monsoon Rainfall","authors":"V.G. Kiran ,&nbsp;Suryachandra A. Rao ,&nbsp;Prasanth A. Pillai ,&nbsp;Rajesh Kumar Singh Maurya ,&nbsp;Ankur Srivastava ,&nbsp;Maheswar Pradhan","doi":"10.1016/j.atmosres.2025.108708","DOIUrl":"10.1016/j.atmosres.2025.108708","url":null,"abstract":"<div><div>The mesoscale eddies present in many dynamic regions of the world ocean are known to modulate wind and precipitation in their vicinity. This study investigates the observed association between eddy activity in the western Bay of Bengal and seasonal rainfall over the monsoon core region during the boreal summer. A novel method is employed to characterise eddy variability in the Bay of Bengal using the Okubo-Weiss (OW) parameter. The anticyclonic (cyclonic) eddy activity in the western Bay correlates with increased (decreased) monsoon rainfall and westerly (easterly) wind anomalies across the monsoon core zone. During years when BoB is dominated by anticyclonic eddies, the seasonal Indian summer monsoon rainfall (ISMR) in this region exceeds the climatological mean by up to 35 % of its standard deviation. A mechanism linking the anticyclonic eddies and the ISMR is proposed here based on the observational data for the 1993–2022 period. The presence of anticyclonic eddies appears to mitigate the detrimental effects of El Niño on east-central Indian rainfall by fostering atmospheric conditions favourable for monsoon low-pressure system formation. Furthermore, years dominated by anticyclonic eddies exhibit a stronger, narrow coastal SST gradient in the northwestern Bay of Bengal, which may further enhance LPS development.</div><div>Methodically structured model sensitivity experiments using a standalone atmospheric model substantiate the impact of mesoscale SST structures and the coastal gradient in the BoB on rainfall, thus providing potential evidence regarding the interplay between eddies and the Indian monsoon system.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"333 ","pages":"Article 108708"},"PeriodicalIF":4.4,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145785331","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":"Cloud microphysical processes of lightning-producing convective clouds over Northeast India: Insights from in-situ and TRMM observations","authors":"Mahen Konwar ,&nbsp;B. Abida Choudhury ,&nbsp;Imolemba Longkumer ,&nbsp;Duncan Axisa","doi":"10.1016/j.atmosres.2025.108704","DOIUrl":"10.1016/j.atmosres.2025.108704","url":null,"abstract":"&lt;div&gt;&lt;div&gt;This study investigates the microphysical processes of lightning-producing convective clouds over Northeast India during September 2009, using unique in-situ measurements from an instrumented aircraft in conjunction with near-simultaneous Tropical Rainfall Measuring Mission (TRMM) satellite overpass observations. TRMM measurements revealed isolated convective cells with reflectivity up to 45 dBZ, storm tops near 14 km, and frequent lightning flashes (2–250 s&lt;sup&gt;−1&lt;/sup&gt;), indicative of mature mixed-phase cumulonimbus systems. Aircraft-based droplet size distribution (DSD) measurements showed progressive spectral broadening with altitude and drizzle onset near the 0 °C isotherm level. Large values of liquid water content (LWC) near it promote the formation of supercooled water in colder regimes. The coexistence of supercooled droplets, ice, and graupel at sub-zero temperatures creates favorable conditions for charge separation. The hydrometeor axis ratio and diameter relationship is evaluated.&lt;/div&gt;&lt;div&gt;Vertical profiles of droplet concentration, LWC, ice water content, effective radius (&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;), and autoconversion rates further highlight active droplet growth through collision–coalescence processes. The autoconversion rate was modulated by updraft transport and feedbacks from droplet depletion on drizzle formation. Scatter plot and normalized DSD analyses revealed distinct microphysical regimes: cloud-only (positive &lt;span&gt;&lt;math&gt;&lt;mi&gt;μ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;, high &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;N&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;w&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;, where &lt;span&gt;&lt;math&gt;&lt;mi&gt;μ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt; is the shape parameter and &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;N&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;w&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;, the intercept parameter of normalized Gamma DSD) and cloud–drizzle (negative &lt;span&gt;&lt;math&gt;&lt;mi&gt;μ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;, reduced &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;N&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;w&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;). In warm, droplet-dominated clouds (2 &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mo&gt;&lt;&lt;/mo&gt;&lt;mi&gt;D&lt;/mi&gt;&lt;mo&gt;&lt;&lt;/mo&gt;&lt;mn&gt;50&lt;/mn&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mi&gt;μ&lt;/mi&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;mo&gt;&gt;&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mo&gt;°&lt;/mo&gt;&lt;mi&gt;C&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;), the relationships between &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;–LWC and &lt;span&gt;&lt;math&gt;&lt;mi&gt;μ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;–LWC become more pronounced. When both cloud droplets and drizzle are included (2 &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mo&gt;&lt;&lt;/mo&gt;&lt;mi&gt;D&lt;/mi&gt;&lt;mo&gt;&lt;&lt;/mo&gt;&lt;mn&gt;50&lt;/mn&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mi&gt;μ&lt;/mi&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;), these relationships weaken. In cold clouds (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;mo&gt;&lt;&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mo&gt;°&lt;/mo&gt;&lt;mi&gt;C&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;), a strong coupling between &lt;span&gt;&lt;math&gt;&lt;mi&gt;μ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;mi&gt;λ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt; emerges. Considering only larger hydrometeors (50 &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mo&gt;&l","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"333 ","pages":"Article 108704"},"PeriodicalIF":4.4,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145785330","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":"Cloud radiative effects over Indian regional atmosphere using CERES observations and machine learning regressions","authors":"Krishnaveni R B ,&nbsp;Jyotirmayee Satapathy ,&nbsp;Buddhi Prakash Jangid","doi":"10.1016/j.atmosres.2025.108705","DOIUrl":"10.1016/j.atmosres.2025.108705","url":null,"abstract":"<div><div>Different atmospheric regimes, primarily governed by Cloud dynamics, have significant influence on the atmospheric radiative properties which, over a long term eventually modifies the regional climate. To study these effects, eleven years (2012−2022) of Clouds and the Earth's Radiant Energy System (CERES) observations of long-wave and short-wave radiation fluxes have been analyzed over India for different atmospheric conditions. Study includes different cloud properties, macro and microphysical parameters as well as optical nature such as cloud cover, Cloud Optical Depth (COD) and Cloud Top Pressure (CTP) along with cloud liquid and ice content and their evolution and distribution in connection with the radiative fluxes. Seasonal studies and their contribution in governing the radiative dynamics of the atmosphere have been emphasized. This case study is intended to provide insight into the cloud and radiation coupled with atmospheric thermodynamics and its sensitivity, independently as well as co-dependently based on statistical analysis through machine learning tools as well. The increased cloud cover, LW absorption and SW reflection is evident over Indian region signifying the modification in the radiation budget in the recent times. Further, more ice, liquid amount, lower cloud temperature, and bigger particles have been responsible for the rise of LW and SW reflected TOA fluxes as well.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"332 ","pages":"Article 108705"},"PeriodicalIF":4.4,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145785332","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":"Spring extreme heat in the Indochina Peninsula enhances the prediction skill of summer precipitation in Central China","authors":"Yihua He ,&nbsp;Wei Lou ,&nbsp;Cheng Sun ,&nbsp;Menghao Dong ,&nbsp;Zichen Song ,&nbsp;Linfeng Shi ,&nbsp;Yibing Tong","doi":"10.1016/j.atmosres.2025.108710","DOIUrl":"10.1016/j.atmosres.2025.108710","url":null,"abstract":"<div><div>Summer precipitation in Central China (CC) is typically influenced by ocean-atmosphere coupling processes. However, the mechanisms through which land surface processes in surrounding regions affect CC precipitation, particularly those over the Indochina Peninsula (ICP), remain poorly understood. We propose that extreme heat events (TX90P) over the ICP during March–April-May (MAM) enhance June–July-August (JJA) precipitation in CC. ICP MAM TX90P establishes a self-reinforcing feedback loop through energy and moisture exchange processes at the land-atmosphere (L-A) interface, thereby amplifying the intensity of extreme heat events. Extreme heat events are accompanied by high-pressure systems with anomalous subsidence of airflow that suppress precipitation and reduce soil moisture (SM). The resulting dry soil establishes a positive feedback mechanism with precipitation, enabling the anomalous SM reduction to persist into JJA. This soil moisture memory effect-induced drought leads to weakened vertical motion over the ICP, promoting the formation of an anticyclonic circulation pattern spanning the ICP and Western Pacific (WP), which subsequently strengthens southwesterly winds that transport moisture toward CC, resulting in enhanced precipitation. Simulations using a Linear Baroclinic Model (LBM) confirm that ICP extreme heat events generate southwesterly wind anomalies, facilitating northeastward moisture transport to CC. A multiple linear regression model incorporating MAM TX90P, preceding winter El Niño-Southern Oscillation (ENSO), and preceding winter Indian Ocean Dipole (IOD) effectively reproduces observed JJA CC precipitation (<em>r</em> = 0.62). This result demonstrates that incorporating extreme heat-related land surface processes significantly improves precipitation prediction skill compared to models relying solely on oceanic variability.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"333 ","pages":"Article 108710"},"PeriodicalIF":4.4,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145785337","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":"Cloud-top height as a leading indicator of tropical cyclone intensity in the Western North Pacific","authors":"Xishu Huang ,&nbsp;Chaohui Chen ,&nbsp;Yuan Sun ,&nbsp;Zhihao Feng ,&nbsp;Wei Zhong ,&nbsp;Hongrang He","doi":"10.1016/j.atmosres.2025.108697","DOIUrl":"10.1016/j.atmosres.2025.108697","url":null,"abstract":"<div><div>Relatively little is known about the role of upper-tropospheric factors in monitoring and predicting tropical cyclone (TC) intensity, despite their significant contribution to TC development. Using data from the International Best Track Archive for Climate Stewardship (IBTrACS) and cloud-top height (CTH) products from the Fengyun-4 A (FY-4 A) satellite, this study found that the mean CTH within a radius of 0–200 km from the TC center exhibited a correlation of 0.47 with TC intensity. This correlation was significantly higher than that of conventional predictors such as sea surface temperature (SST), which showed a correlation of 0.32. Moreover, changes in CTH typically preceded changes in TC intensity by approximately 12 to 15 h, suggesting that CTH may serve as a leading indicator of TC intensity. The study also examined the mechanisms through which CTH influences TC intensity. Results indicated that an increase in CTH was generally associated with enhanced TC outflow, which in turn strengthened the TC's secondary circulation. This process improved the efficiency of the TC Carnot heat engine and ultimately favored TC intensification.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"332 ","pages":"Article 108697"},"PeriodicalIF":4.4,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145785298","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":"An innovative approach to ZDR data assimilation using an ensemble Kalman filter: a proof-of-concept study","authors":"Bing-Xue Zhuang ,&nbsp;Kao-Shen Chung ,&nbsp;Wei-Yu Chang ,&nbsp;Chih-Chien Tsai ,&nbsp;Yi-Chiang Yu","doi":"10.1016/j.atmosres.2025.108703","DOIUrl":"10.1016/j.atmosres.2025.108703","url":null,"abstract":"<div><div>Differential reflectivity (<em>Z</em>_<em>DR</em>) observations from dual-polarimetric radars are directly related to the mean diameter of raindrops. To leverage this one-to-one relationship, the present study develops a mean diameter update (MDU) approach based on a local ensemble transform Kalman filter radar data assimilation system for <em>Z</em>_<em>DR</em> assimilation, which enables the explicit updating of the mass-weighted mean diameter (<em>D</em>_<em>m</em>) of raindrops. A series of assimilation experiments using both pseudo and real radar observations is conducted to examine the feasibility of the MDU approach. The results of the scalar assimilation experiment indicate that explicitly updating <em>D</em>_<em>m</em> by the assimilated pseudo <em>Z</em>_<em>DR</em> observation further enhances the accuracy of the <em>D</em>_<em>m</em> analysis. The single-pseudo-observation assimilation experiment reveals that the MDU approach effectively leverages the strong correlation between simulated <em>Z</em>_<em>DR</em> and <em>D</em>_<em>m</em>, and more corrections are propagated to the grid points near the pseudo <em>Z</em>_<em>DR</em> observation. In the observation system simulation experiments (OSSEs) for the Mei-Yu front case, assimilating pseudo <em>Z</em>_<em>DR</em> observations with the MDU approach reduces analysis errors of simulated <em>Z</em>_<em>DR</em> and rainwater state variables in each cycle. The forecast performance is the most favorable in terms of the forecast skill score and the rainfall probability when the forecast is initiated with more accurate microphysical states obtained by the MDU approach. Regarding the real-observation experiments, the analysis and forecast results are consistent with those of the OSSEs. The application of the MDU approach to both pseudo and real observations confirms its ability to exploit the intrinsic relationship between <em>Z</em>_<em>DR</em> and <em>D</em>_<em>m</em>, improving the accuracy of analyses and forecasts.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"332 ","pages":"Article 108703"},"PeriodicalIF":4.4,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145785297","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":"A statistical evaluation of sudden stratospheric warming events in the southern hemisphere based on a new definition","authors":"Ying Li ,&nbsp;Yunbin Yuan ,&nbsp;Wenwu Ding ,&nbsp;Xinyu Zhang","doi":"10.1016/j.atmosres.2025.108706","DOIUrl":"10.1016/j.atmosres.2025.108706","url":null,"abstract":"<div><div>Sudden stratospheric warming (SSW) events in the southern hemisphere were found to have strong influences on the Earth's atmosphere. However, statistical evaluations of such events were rarely carried out. This study introduces a new definition to detect and monitor SSW events in the southern hemisphere from a statistical point of view. The new method accounts characteristics of such events and uses three metrics to monitor stratospheric warmings in the three altitude layers of 20–25 km, 25–30 km and 30–35 km. If one of the metrics is continuously larger than a minimum threshold for more than 5 days, then an SSW event is detected and a main warming phase is recorded. Subsequently, the onset date, warming strength, duration, mean warming area and location of an event are recorded. The new method is applied to 42 years' reanalysis data from 1980 to 2021. Results show that the new definition can detect both strong and weak events. The frequency of all SSW events is 0.38/year and of strong events is 0.26/year in this study. Seasonally, SSW events occur most often in the three months from July to September and geographically most often in the eastern longitude side of southern polar region. It is also found that the number, strength and duration of SSW events from the latter two decades of 2001–2020 are larger than that of the previous two decades of 1981–2000 in this study though further studies are required to consolidate this conclusion.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"332 ","pages":"Article 108706"},"PeriodicalIF":4.4,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145766046","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":"Climatological characteristics of ITCZ over the South Asian monsoon domain: Using multivariate probabilistic approach","authors":"Priya Kumari ,&nbsp;B. Preethi ,&nbsp;M. Mujumdar","doi":"10.1016/j.atmosres.2025.108709","DOIUrl":"10.1016/j.atmosres.2025.108709","url":null,"abstract":"<div><div>The Intertropical Convergence Zone (ITCZ) is a zonally oriented tropical band where trade winds converge, triggering deep convection and heavy rainfall, and produces about 32% of global precipitation. Studies indicate that the migration of ITCZ significantly influences the climate of tropical regions and adjacent areas. It is to be noted that during the summer monsoon (June–September) season, the ITCZ undergoes a pronounced northward shift in the South Asian monsoon region which is attributed to the displacement of zero absolute vorticity contour northward of the equator. However, changes in local precipitation are not necessarily correlated with the position of the zonal mean ITCZ, which point towards the importance of analyzing ITCZ dynamics on both regional and seasonal scales. A comparative analysis of various metrics based on precipitation, convection, moisture, and circulation reveals notable differences in estimating the ITCZ location. To address this, a multivariate probabilistic approach, combining precipitation and mean meridional mass flux, has been applied. This method effectively captures the seasonal migration of the ITCZ from boreal winter to boreal summer season, and also resolves its regional variations, providing a clearer picture of onset, peak, and withdrawal phases of South Asian Summer monsoon season.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"332 ","pages":"Article 108709"},"PeriodicalIF":4.4,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145785336","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}