Atmospheric Research最新文献

{"title":"Understanding the aerosol impact on the electrification of PyroCb thunderstorm","authors":"Surajit Das Barman,&nbsp;Rakibuzzaman Shah,&nbsp;Syed Islam,&nbsp;Apurv Kumar","doi":"10.1016/j.atmosres.2025.108029","DOIUrl":"10.1016/j.atmosres.2025.108029","url":null,"abstract":"<div><div>Understanding and predicting pyrocumulonimbus (pyroCb) thunderclouds is challenging due to their unpredictable nature and potential to exacerbate wildfires. This study employs a three-dimensional (3D) numerical model with a non-inductive electrification mechanism to explore how fire-produced aerosol concentrations influence the charge structure and lightning activity in pyroCb. Aerosol particle concentrations ranging from 100 to 20,000 cm⁻³ were considered to generate realistic thundercloud charge structures, with the cumulus cloud setup based on environmental conditions derived from an inverted-V sounding profile. The SP98 non-inductive electrification scheme models charge transfer in pyroCb, and the Poisson equation is solved to identify regions where lightning discharges are likely to initiate, though actual discharges are not simulated. For aerosol concentrations between 500 and 5000 cm⁻³, negative non-inductive charging dominates, while extreme aerosol cases (<span><math><mo>≥</mo></math></span>5000 cm⁻³) enhance positive charging at altitudes of 3–7 km. These findings suggest that non-inductive charge separation between ice crystals and graupel leads to realistic charge structures under pyroconvective conditions simulated in this study, reflecting moderate-to-high aerosol environments characteristic of wildfire-driven pyroCb events. As aerosol concentrations increase from 500 to 5000 cm⁻³, the charge structure evolves from a dipole to a tripole (at 1000 cm⁻³) and eventually to an inverted dipole, enabling intra-cloud (IC) and negative cloud-to-ground (-CG) lightning. At higher concentrations (10,000–20,000 cm⁻³), a multi-layer charge configuration emerges, favoring intense positive cloud-to-ground (+CG) strokes. Sensitivity analysis reveals that low-to-moderate aerosol levels with strong wind shear promote IC lightning, while high aerosol levels favor +CG flashes. These findings highlight the complex interactions driving pyroCb dynamics and the importance of integrated modelling to predict wildfire-induced thunderstorms.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"320 ","pages":"Article 108029"},"PeriodicalIF":4.5,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143644145","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":"Terrain and urban impacts on summer extreme precipitation over Henan, China: A synoptic and simulation analysis","authors":"Shuang Chen ,&nbsp;Ben Yang ,&nbsp;Anning Huang ,&nbsp;Yan Zhang","doi":"10.1016/j.atmosres.2025.108033","DOIUrl":"10.1016/j.atmosres.2025.108033","url":null,"abstract":"<div><div>The impacts of terrain and urban surfaces on regional hourly extreme precipitation events (RHEPE) in Henan Province of China under specific synoptic conditions remain unclear. In this study, we first identify the dominant synoptic patterns associated with the summer RHEPEs in Henan and surrounding areas by employing spectral clustering methods, revealing that 86 % of RHEPEs are induced by the low vortexes and 14 % by the tropical cyclones, with the latter contributing to the most extreme RHEPEs. Then, based on numerical experiments and moisture budget decomposition, we quantify the effects of terrain and urban surfaces on RHEPE under the most extreme synoptic pattern featured by tropical cyclones. Results suggest that the terrains cause remarkable increases in precipitation primarily along the windward slopes of the Funiu Mountains and Taihang Mountains by 34 % and 26 %, respectively, this can be explained by the enhanced dynamical component of moisture convergence due to the blocking effect of terrains. Compared to the terrain, the impacts of urban surfaces are much smaller (only 1 %) and spatially limited. The much larger surface roughness in the urban areas reduces the horizontal wind speed and causes weakened wind convergence, leading to decreased precipitation over the urban areas. Meanwhile, when traversing the urban areas, the horizontal winds bifurcating and rejoining in the downwind areas increase the low-level convergence and precipitation there. Findings of this study may deepen our understanding of the influences of terrain and urban surfaces on the RHEPE and associated mechanisms under the extreme synoptic pattern.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"320 ","pages":"Article 108033"},"PeriodicalIF":4.5,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143580846","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":"Evaluating clear-sky assimilation of FengYun-3E microwave radiance data in predicting multiple tropical cyclones over the Western North Pacific","authors":"Di Fang ,&nbsp;Guanghua Chen ,&nbsp;Xingou Xu ,&nbsp;Yuhui Zhao ,&nbsp;Ziqing Wang","doi":"10.1016/j.atmosres.2025.108025","DOIUrl":"10.1016/j.atmosres.2025.108025","url":null,"abstract":"<div><div>Since the successful launch and operation of the FengYun-3E (FY-3E) satellite, the assessment of its data quality and applications has garnered significant attention. By comparison with previous studies focusing on the assessment on a single case, this research assimilates the Microwave Humidity Sounder-2 (MWHS-2) and the Microwave Temperature Sounder-3 (MWTS-3) data to evaluate the track and intensity prediction of 19 tropical cyclones (TCs) over the western North Pacific (WNP). This comprehensive investigation seeks to unravel the contributions of microwave radiance onboard FY-3E to the initial fields in the multi-typhoon predictions. For each TC case, three experiments are carried out to evaluate the effect of microwave radiance data on clear-sky assimilation: the control experiment (CONV) assimilates only conventional data, while the other two experiments incorporate MWHS-2 (MWHS) and MWTS-3 (MWTS) data, respectively. The results indicate that MWHS and MWTS exert distinct effects on dynamical and thermodynamic variables across various atmospheric levels. The positive impact of MWHS and MWTS on the track and intensity forecast has been proven, respectively, with the root mean square errors reduced by 3.86 % for track, 4.76 % for maximum wind speed (MWS), and 7.78 % for minimum surface level pressure (MSLP) relative to CONV. For the three-day average forecast errors, the MWHS exhibits the lowest daily mean track error, while the MWTS primarily contributes to reducing the MSLP error on the second day and the MWS error on the first and third days.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"320 ","pages":"Article 108025"},"PeriodicalIF":4.5,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143609624","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":"Type-based assessment of aerosol direct radiative effects: A proof-of-concept using GEOS-Chem and CATCH","authors":"Bethany Sutherland ,&nbsp;Nicholas Meskhidze","doi":"10.1016/j.atmosres.2025.108036","DOIUrl":"10.1016/j.atmosres.2025.108036","url":null,"abstract":"<div><div>The radiative perturbation of the Earth's energy balance caused by all aerosols, the direct radiative effect (DRE), and anthropogenic aerosols, the direct radiative forcing (DRF), remain major sources of uncertainty in climate projections. Here we propose a method for determining DRE and DRF that makes use of the High Spectral Resolution Lidar (HSRL)-retrieved aerosol loading and derived aerosol types (i.e. dust, marine, urban, smoke, etc.) in combination with aerosol-type specific optical properties. As the global spatiotemporal distributions of HSRL-derived aerosol types are not currently available, the methodology is tested here using a global 3-D model of atmospheric chemistry (GEOS-Chem) along with Creating Aerosols from CHemistry (CATCH) algorithm-generated aerosol types analogous to ones derived by HSRL. In this method, the Rapid Radiative Transfer Model for General Circulation Models (RRTMG) is used to perform radiative transfer calculations with the single scattering albedo (SSA) and asymmetry parameter (g) of atmospheric particles assigned based on the aerosol type in each grid box. Average GEOS-Chem/CATCH-derived all-sky DRE and DRF across the North American domain are estimated to be −1.98 W/m² and − 0.77 W/m², respectively between mid-January and early February 2013 and − 4.20 W/m² and − 1.41 W/m² respectively between mid-July and early August 2014. Sensitivity studies revealed that the scheme may produce up to about ±0.42 W/m² and ± 0.21 W/m² uncertainty in DRE and DRF, respectively, related to variability in aerosol type-specific optical properties. This study presents a new way of determining DRE and DRF estimates once global retrievals of aerosol intensive parameters by HSRL become available.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"320 ","pages":"Article 108036"},"PeriodicalIF":4.5,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143594185","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":"Extreme wildfires over Northern Greece during Summer 2023 – Part B. Adverse effects on regional air quality","authors":"Maria-Elissavet Koukouli,&nbsp;Andreas Pseftogkas,&nbsp;Dimitris Karagkiozidis,&nbsp;Marios Mermigkas,&nbsp;Thomas Panou,&nbsp;Dimitris Balis,&nbsp;Alkiviadis Bais","doi":"10.1016/j.atmosres.2025.108034","DOIUrl":"10.1016/j.atmosres.2025.108034","url":null,"abstract":"&lt;div&gt;&lt;div&gt;The frequency, severity, and duration of wildfires are on the rise worldwide, underscoring the importance of comprehending the health impacts of wildfire exposure. The main aim of this work is to examine the effects that the Northern Greece forest fires during August 2023 had on regional air quality levels. On August 21st, a massive forest fire started within the Dadia Forest National Park, a protected area, nearby the city of Alexandroupoli. During the nearly ten-day duration of the fire, approximately 80,000 ha burned, while the strong prevailing easterly winds transported smoke particles and biomass burning gases over Northern Greece and the Mediterranean Sea, reaching the coasts of Italy and Tunisia. Using both spaceborne observations of nitrogen dioxide (NO&lt;sub&gt;2&lt;/sub&gt;), formaldehyde (HCHO) and carbon monoxide (CO), as well as ground-based instrumentation in the city of Thessaloniki, the extend of the degradation of air quality has been quantified. The spatially resolved Sentinel-5P TROPOspheric Monitoring Instrument (S5P/TROPOMI) observations showed how the fire plumes spread throughout Northern Greece, degrading massively the air quality near the fire event as well as over Thessaloniki, some 300 km to the west. NO&lt;sub&gt;2&lt;/sub&gt; levels were enhanced up to 82 % over the fire location whereas in the metropolis of Thessaloniki by 36 %, testifying to the extent of the fire, the dispersion of the plume and the emission strength. During the main fire days HCHO levels were shown to be enhanced by 54 % in the greater area of Alexandroupoli and by 114 % in the vicinity of Thessaloniki, in line with other works. The longer-lived CO was found similarly enhanced in both locations, ∼26 %, with a longer lasting effect to regional air quality. Ground-based remote sensing resulted in similar findings with MAX-DOAS spectrophotometer observations of nitrogen dioxide capturing the build-up of the transported NO&lt;sub&gt;2&lt;/sub&gt; load over Thessaloniki with morning levels reaching 30 Pmolec/cm&lt;sup&gt;2&lt;/sup&gt;, testifying to the magnitude of the transported NO&lt;sub&gt;2&lt;/sub&gt; loads well beyond the stable variability of the typical August mean NO&lt;sub&gt;2&lt;/sub&gt; levels of 10 Pmolec/cm&lt;sup&gt;2&lt;/sup&gt;. The MAX-DOAS also measured increased formaldehyde levels throughout the days of the fire event, between 25 and 35 Pmolec/cm&lt;sup&gt;2&lt;/sup&gt;, unaffected by the photochemical processes destroying NO&lt;sub&gt;2&lt;/sub&gt;, and well beyond the typical summertime levels of ∼12 Pmolec/cm&lt;sup&gt;2&lt;/sup&gt;. FTIR spectroscopy observations, also routinely performed over Thessaloniki, revealed that the long-lived carbon monoxide levels exceeded the expected background loads by more than 100.00 ± 10.61 ppb on the second major fire day. The predicted frequency increase of such major wildfire events places an imperative need for changes in the typical urban air quality monitoring practices currently in place, to account for unexpected degradation of the breathable air, as well as changes on how mitigation measu","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"320 ","pages":"Article 108034"},"PeriodicalIF":4.5,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143636871","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":"Local and regional enhancements of GHGs in Thessaloniki, inferred from ground-based FTIR measurements","authors":"Marios Mermigkas ,&nbsp;Chrysanthi Topaloglou ,&nbsp;Dimitrios Balis ,&nbsp;Frank Hase ,&nbsp;Darko Dubravica","doi":"10.1016/j.atmosres.2025.108035","DOIUrl":"10.1016/j.atmosres.2025.108035","url":null,"abstract":"<div><div>Global warming and subsequent climate change are currently a major issue both in the scientific community and the society. Therefore it is highly important to consistently monitor the concentrations of greenhouse gases that affect the incoming-outgoing energy balance. To that end, a portable Bruker EM27/SUN FTIR spectrometer is operated in Thessaloniki, Greece since January 2019, performing measurements of total column-averaged dry air mole fractions of trace gases, denoted as X-gases. In this study, we demonstrate the utility of available measurements of greenhouse gases (GHGs) to identify the origin of enhanced concentrations. Copernicus Atmosphere Monitoring Service (CAMS) reanalysis data are used synergetically with FTIR measurements. XCO₂ shows an obvious annual increase (over 2.2 ppm per year) and a clear seasonal variation with high increased concentrations during cold season and decreased concentration during summer period due to photosynthesis activity. XCH₄ shows an annual increase and a positive trend. The continuous fire episodes in Athens and North Evia during July and August 2021 led to an unprecedented increase in the concentrations of CO of over 130 %, compared to the typical averaged mean values during August in Thessaloniki. In this paper we investigate the seasonal dependency between CO-CO₂ and CO-CH₄ enhancements with respect to the prevailing wind direction and we examine if meteorological parameters, such as wind direction and speed, could reveal the origin of enhanced X-gas variations. We applied two different approaching methods to detect long-term and short-term signals of the trace gases. In general, concerning the FTIR measurements, during summer and autumn XCO₂, XCO and XCH₄ enhancements are observed for low and medium speed winds. Winds mainly originating from SW directions have transported large amounts of CO₂, CO and CH₄ from the big fires near Athens and N. Evia in summer 2021 to Thessaloniki. The fire emissions generate higher variability of the columns of target gases (over 0.022 ppm in the S and SW wind direction).</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"319 ","pages":"Article 108035"},"PeriodicalIF":4.5,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143562627","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":"Characteristics of orographic clouds and associated mechanisms in the Qilian Mountains, northeastern Tibetan Plateau based on FengYun-4A satellite TBB product","authors":"Yi Chang ,&nbsp;Qianrong Ma ,&nbsp;Peng Qi ,&nbsp;Xueliang Guo ,&nbsp;Dawei Lin ,&nbsp;Lijun Guo ,&nbsp;Di Di ,&nbsp;Yang Zhao ,&nbsp;Hui Wang ,&nbsp;Tianyu Chen","doi":"10.1016/j.atmosres.2025.108031","DOIUrl":"10.1016/j.atmosres.2025.108031","url":null,"abstract":"<div><div>The Qilian Mountains (QM) in northwest China is a key source of orographic cloud formation, significantly influencing regional weather, climate, and hydrological balance. However, due to the sparse distribution of ground-based observational stations, the characteristics of orographic clouds and their associated precipitation remain insufficiently understood. Utilizing FengYun-4A black body temperature (TBB) data from 2018 to 2021 in boral summer, this study investigated the spatial and diurnal characteristics of orographic clouds and associated mechanisms over the QM. Results indicate that orographic clouds primarily form over the mountainous terrain, with deep convective clouds concentrated in the central and eastern QM. A distinct diurnal cycle is observed, with peak cloud activity occurring in the afternoon to early evening (15:00–19:00 local solar time), minimal activity late at night, and the weakest development in the morning. These variations are more pronounced in the central and eastern QM, where cloud formation persists for longer durations, compared to the western region. Three dominant diurnal cloud cycles are identified in the southeast, northeast, and eastern fringes of the western, central, and eastern QM, respectively, along with smaller-scale cycles along mountain ridges. Orographic cloud formation is driven by the convergence of low-level westerlies and the Asian monsoon, with moisture contributions from the westerlies, the Tibetan Plateau, and the monsoon system. Additionally, interactions between solar heating and complex terrain shape the spatial and diurnal distribution of these clouds. These findings enhance our understanding of regional water cycles and provide valuable insights for weather and climate research.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"320 ","pages":"Article 108031"},"PeriodicalIF":4.5,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143636867","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":"Observational climatology and interannual variability of the spring rainy season onset over southern China: Objective definition and influence from tropical Pacific Ocean","authors":"Kexu Zhu ,&nbsp;Wen Chen ,&nbsp;Peng Hu ,&nbsp;Yehong Luo ,&nbsp;Ruowen Yang ,&nbsp;Linwei Jiang ,&nbsp;Qingyu Cai ,&nbsp;Lu Gao ,&nbsp;Jingnan Li ,&nbsp;Yongmao Peng ,&nbsp;Changhao Wu ,&nbsp;Ziqi Niu","doi":"10.1016/j.atmosres.2025.108030","DOIUrl":"10.1016/j.atmosres.2025.108030","url":null,"abstract":"<div><div>Based on multiple datasets, the spring rainy season onset (RSO) date over southern China is objectively determined and validated, and the relationship between RSO and tropical Pacific SST is then explored. The RSO date is defined as the time when the cumulative precipitation departure over southern China reaches its minimum value, with a climatological onset date of March 14 and a standard deviation of 22 days. The RSO is closely linked to the sudden changes in atmospheric circulations and abrupt emergence of rainfall and convection, displaying strong interannual variability. An early RSO is characterized by an increase in rainfall during February and March, and is associated with a zonal sea surface temperature (SST) dipole in the tropical Pacific. This is because the concurrent cooler SST in the tropical Western Pacific triggers lower-tropospheric southwesterly wind anomalies over the western North Pacific through Matsuno-Gill-type Rossby wave response. These wind anomalies then enhance water vapor transport and warm advection towards southern China, which, in turn, fosters anomalous upward motion combined with vorticity advection. Such anomalous ascending motion is favorable for the increased precipitation and the advanced RSO over southern China.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"320 ","pages":"Article 108030"},"PeriodicalIF":4.5,"publicationDate":"2025-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143562133","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":"Two major sudden warming events in the unprecedentedly active stratosphere during the boreal winter of 2023/2024 and their distinct surface impacts over China","authors":"Jincai Xie ,&nbsp;Jinggao Hu ,&nbsp;Xuancheng Li ,&nbsp;Jing-Jia Luo ,&nbsp;Haiming Xu ,&nbsp;Yanpei Jia","doi":"10.1016/j.atmosres.2025.108032","DOIUrl":"10.1016/j.atmosres.2025.108032","url":null,"abstract":"<div><div>In the boreal winter of 2023/2024, the 10-hPa stratosphere experienced unprecedented planetary wave activity. This led to two major sudden stratospheric warming (SSW) events occurring on January 16 and March 4. The onset processes of both SSWs demonstrated clear stratosphere-troposphere coupling. On one hand, notable precursor signals were detected in the troposphere before each SSW. Approximately 15 days prior to the first SSW, a markedly intensified 500-hPa high pressure emerged over the high-latitude Atlantic, resulting in the strongest wave 3 in the troposphere since 1979. Additionally, an anomalous high over eastern Europe served as a precursor signal for the second SSW, contributing to a rapid increase in waves 1 and 2 approximately 20 days before its occurrence. On the other hand, these two SSWs exhibited distinct impacts on subsequent surface air temperature (SAT) over China. Specifically, the first SSW was characterized as a reflecting event. Following its onset, strong planetary wave reflections were observed in the troposphere over the Siberian and North Pacific regions, leading to local high-pressure ridge development. The two ridges, along with troughs between them, created an “inverted Ω-shaped” circulation pattern and caused a cold wave across China during January 18–22. In contrast, the second SSW was identified as an absorbing event; its impact aligned with typical effects of SSWs on SAT over Eurasia. After its onset, a negative phase of Northern Annular Mode emerged in the stratosphere and propagated downward into the troposphere over time, resulting in warming conditions over China during the following month.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"319 ","pages":"Article 108032"},"PeriodicalIF":4.5,"publicationDate":"2025-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143552726","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":"Radar characteristics of seeded and unseeded hail clouds in Romania","authors":"Vasilică Istrate PhD ,&nbsp;Serghei Eremeico Eng. ,&nbsp;Lucian-Ionuț Lazăr Eng. ,&nbsp;Dragoș Andrei Sîrbu Eng. ,&nbsp;Eduard Popescu ,&nbsp;Emil Sîrbu PhD ,&nbsp;Doru Dorian Popescu Eng.","doi":"10.1016/j.atmosres.2025.108028","DOIUrl":"10.1016/j.atmosres.2025.108028","url":null,"abstract":"<div><div>This study evaluates the effectiveness of silver iodide (AgI) cloud seeding in Romania by comparing radar-derived parameters of 20 seeded and 20 unseeded severe hailstorms observed between 2017 and 2022. Radar data from S and C-band systems were analyzed using six key parameters, including maximum reflectivity (Zmax), vertically integrated liquid (VIL), Volume of the cloud with reflectivity more than 35 dBZ (dV35) and height of the 45dBZ echo above the environmental melting level (dH45). Statistical comparisons were conducted using the Mann-Whitney <em>U</em> test to identify significant differences between the two storm groups. The results reveal statistically significant differences in radar metrics between seeded and unseeded storms, with seeded storms generally exhibiting lower parameter values. For instance, median Zmax was 58 dBZ for seeded storms compared to 60 dBZ for unseeded storms, while VIL medians were 19 kg/m² and 27 kg/m², respectively. Similarly, dV35 was reduced by approximately 22 % in seeded storms. These differences indicate that seeding modifies storm microphysical processes and dynamics, potentially suppressing hail formation. However, variability across storm environments and radar categories highlights some uncertainties. Natural fluctuations in convective processes and challenges in tracking seeding agent dispersion complicate the interpretation of results. Nonetheless, the statistical significance of observed differences supports the hypothesis that AgI seeding influences storm characteristics. This study provides quantitative and statistical evidence of seeding effect and underscores the need for further research using advanced radar technologies and larger datasets to refine hail suppression methodologies.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"320 ","pages":"Article 108028"},"PeriodicalIF":4.5,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143562132","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}