Journal of Geophysical Research: Atmospheres最新文献

{"title":"Regional and Seasonal Hydrological Changes With and Without Stratospheric Aerosol Intervention Under High Greenhouse Gas Climates","authors":"Abolfazl Rezaei,&nbsp;John Moore,&nbsp;Simone Tilmes,&nbsp;Khalil Karami","doi":"10.1029/2025JD044163","DOIUrl":"https://doi.org/10.1029/2025JD044163","url":null,"abstract":"<p>Stratospheric aerosol intervention (SAI) is being explored for its potential to reduce greenhouse gas (GHG) induced climate damages. We assess the effectiveness of two SAI experiments, G6Sulfur and Geo SSP5-8.5 1.5 (here called Geo-SAI), using the CESM2(WACCM6) model to reduce hydrological changes under high-emission SSP5-8.5 (no mitigation) pathway. Geo-SAI stabilizes near surface global temperatures at 1.5°C above preindustrial levels, whereas G6Sulfur limits temperature rises to those under the SSP2-4.5 scenario. In our findings, Geo-SAI reverts many, but not all, hydrological changes induced by SSP5-8.5 restoring global and regional means, seasonal amplitudes, and peak timings. G6Sulfur delivers smaller restorations, as expected, due to its smaller prescribed forcing. In hyperarid regions such as the Middle East, both SAI scenarios improve water storage compared with both SSP5-8.5 and present conditions. However, in wetter or cooler climates, such as the Amazon, middle and southern Africa and east Europe, they only partly reverse the reductions in available water (AW) and runoff caused by high GHG emissions. Residual warming and snowmelt dynamics play an important role in runoff at mid-to-high latitudes. Additionally, SAI does not completely suppress GHG-induced vegetation expansion and so over-reduces global runoff in three latitude bands: 45°–65°N, 45°–65°S, and 30°S to 0 with end-of-century decreases of 4.1% under G6Sulfur and 7.3% under Geo-SAI despite mean AW levels remaining close to present-day. These findings emphasize that although SAI mitigates many climate-driven hydrological disruptions, its unintended effects on runoff, vegetation feedback, and regional water availability warrants study—especially in regions heavily dependent on surface water resources.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 12","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144367170","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":"Precipitation Over Complex Mountain Terrain in a Convection-Permitting Regional Climate Model","authors":"Stephen J. Stuart,&nbsp;Samuel M. Dean,&nbsp;Andrew N. Mackintosh,&nbsp;Abha Sood,&nbsp;Peter B. Gibson,&nbsp;Stuart Moore,&nbsp;Elizabeth J. Kendon","doi":"10.1029/2024JD042773","DOIUrl":"https://doi.org/10.1029/2024JD042773","url":null,"abstract":"<p>Orographic precipitation is a critical freshwater source and major flooding hazard, but its distribution and behavior over complex terrain are often uncertain due to sparse observations. We examine precipitation and its drivers in one of the wettest regions in the world, the Southern Alps of New Zealand (NZ), using the first multi-decadal simulation by a convection-permitting regional climate model across all mainland NZ at 2.2 km grid-scale. Model skill is primarily assessed against direct measurements by more than 170 rain gauges to avoid uncertainty commonly introduced by gridded observations in remote regions. Peak intensity and duration of sub-daily rainfall over mountains appear markedly improved in the 2.2 km model relative to the 12 km driving model. The orientation of water vapor flux relative to the mountain barrier strongly affects both climatological and daily extreme precipitation. Transects illustrate the influence of steep local topography on strong landfalling atmospheric rivers to produce high vertical velocities and extremely high accumulations of rainfall over windward upper mountain flanks, which do not appear unreasonable against available gauge observations. These transects also reveal the finer spatial structure of mountain waves in the 2.2 km model, which may contribute to its more realistic windward enhancement of orographic precipitation, but with excessive leeward precipitation and an annual mean dry bias over mountains. Despite the computational burden, these results support further targeted dynamical modeling at kilometer scales to improve physical understanding of precipitation in the current climate and its potential future change in NZ and other mountainous regions of the world.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 12","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JD042773","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144367172","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":"Effects of Soil Moisture in Northern Tibetan Plateau on Summer Precipitation in Northwest China","authors":"Fuquan Lu,&nbsp;Haipeng Yu,&nbsp;Zeyong Hu,&nbsp;Yongkun Xie,&nbsp;Dongping Bai,&nbsp;Xin Wang,&nbsp;Shanling Cheng,&nbsp;Haojie Wu,&nbsp;Bofei Zhang","doi":"10.1029/2025JD043690","DOIUrl":"https://doi.org/10.1029/2025JD043690","url":null,"abstract":"<p>Soil moisture (SM) on the Tibetan Plateau (TP), a crucial climate variable with “memory,” influences the East Asia climate by modulating surface energy and water vapor exchanges. Understanding the relationship between TP soil moisture (TPSM) and summer precipitation in Northwest China (NWC) is essential for improving climate predictions for East Asia. However, most existing studies have focused on the connection between TPSM and the climate of East Asian monsoon region, whereas the mechanisms by which TPSM influence precipitation in NWC, a nonmonsoonal area, remain underexplored. This study investigates how spring anomalies of TPSM persist into summer and influence summer precipitation in NWC. The results indicate that anomalies in spring TPSM can initiate a positive feedback with precipitation, which affects the intensity of plateau monsoon and contributes to the persistence of SM anomaly from spring to summer. During summer, positive SM anomalies in northern TP facilitate maintaining cyclonic circulation anomalies over western TP and trigger eastward-propagating Rossby waves that induce anticyclonic circulation anomalies over eastern NWC. The anomalous circulation results in upward motion in the western NWC and subsidence in the eastern NWC enhancing precipitation in the western NWC while reducing the precipitation in the north. Finally, the findings from the circulation analysis are validated through numerical model simulations. This study provides valuable insights into the climatic effects of TPSM and offers important implications for precipitation prediction in NWC.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 12","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144367171","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 Integrated Analysis of Ozone and Carbon Monoxide Over the Western Pacific Using Satellite and Aircraft Measurements During the ACCLIP Summer Campaign 2022","authors":"Juseon Bak,&nbsp;Joowan Kim,&nbsp;Ja-Ho Koo,&nbsp;Laura L. Pan,&nbsp;Ju-Mee Ryoo,&nbsp;Paul A. Newman,&nbsp;Alessandro Franchin,&nbsp;Xiong Liu,&nbsp;Gonzalo G. Abad,&nbsp;Hyo-Jung Lee,&nbsp;WonBae Jeon,&nbsp;Cheol-Hee Kim","doi":"10.1029/2024JD042771","DOIUrl":"https://doi.org/10.1029/2024JD042771","url":null,"abstract":"<p>The western Pacific exhibited a complex interplay of monsoonal dynamics and transport during the Asian Summer Monsoon Chemical &amp; Climate Impact Project (ACCLIP) airborne field campaign in summer 2022. We analyze in situ observations of ozone (O₃) and carbon monoxide (CO) from 29 research flights—profiling over South Korea and cruising over the western Pacific —and balloon soundings in South Korea and Taiwan. In the upper troposphere (UT), a twofold enhancement in CO was observed across the mid-latitudes of the western Pacific, driven by large-scale uplift and outflow associated with the Asian Summer Monsoon (ASM) system. Observational evidence of enhanced UT O₃ in conjunction with its primary precursor, nitrogen dioxide (NO₂), was also presented. Satellite observations from the TROPOspheric Monitoring Instrument (TROPOMI) and Microwave Limb Sounder (MLS) were integrated with two selected flight cases to explore transport events and to provide broader spatial context. On July 31, the ASM anticyclone manifested in two distinct modes, South Asia High (SAH) and Western Pacific High (WPH). The SAH was filled with polluted air masses uplifted from the Asian boundary layer while the WPH was sustained by deep maritime convection. Both flight and satellite data captured polluted air parcels over the tropical western Pacific that had detached from the “main” anticyclonic eddy. By examining the case on August 6, we observed that the western Pacific was strongly modulated by low-level westerlies and the eastward extension of the ASM anticyclone and isentropic mixing near the tropopause.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 12","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JD042771","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144336080","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":"Zonal Asymmetry in Ozone Variations Over Antarctic Stations During the Life Cycle of Sudden Stratospheric Warmings","authors":"Ruixian Yu,&nbsp;Asen Grytsai,&nbsp;Gennadi Milinevsky,&nbsp;Oleksandr Evtushevsky,&nbsp;Andrew Klekociuk,&nbsp;Yu Shi,&nbsp;Oleksandr Poluden,&nbsp;Xiaolong Wang,&nbsp;Oksana Ivaniha","doi":"10.1029/2024JD042896","DOIUrl":"https://doi.org/10.1029/2024JD042896","url":null,"abstract":"<p>The zonal asymmetry in the Antarctic total ozone column (TOC) has been widely studied in recent decades. However, little is known about how spatially dependent the TOC response is to sudden stratospheric warmings (SSWs). This paper analyzes the connection of zonally asymmetric variations of TOC with SSWs in September 1988, 2002, and 2019. The analysis is based on time series for 16 Antarctic research stations, gridded fields (MSR-2 TOC data), and the amplitude of zonal waves 1 and 2 in geopotential height (MERRA-2 reanalysis). We use a superposed epoch analysis for ±60-day time lags relative to the SSW central date to capture the main stages of the SSW life cycle. According to the TOC asymmetry pattern, a division between the Eastern Hemisphere (EH) and Western Hemisphere (WH) stations is used. The main results are zonally asymmetric variations in TOC anomalies near the SSW onset with the stronger (weaker) maximum in EH (WH), statistically significant at the 95% (89%) confidence level; precursor properties of the persistently growing positive anomalies in EH, and difference in timing of response maxima at day 0 in EH and day 7 in WH. These are previously unknown regional manifestations of Antarctic TOC anomalies. The results reveal statistically significant indicators of the possible SSW onset with a 1–2 weeks lead time. The dominant role of wave 1 and the zonally asymmetric Brewer–Dobson circulation in the observed EH–WH asymmetry is discussed.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 12","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144336108","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":"Effects of Soil Moisture Heterogeneity on Temperature-Humidity Dissimilarity in the Convective Boundary Layer","authors":"Cheng Liu,&nbsp;Heping Liu,&nbsp;Jianping Huang,&nbsp;Xiaozhen Fang,&nbsp;Ren-Guo Zhu,&nbsp;Wei Guo,&nbsp;YuanYuan Pan","doi":"10.1029/2025JD043698","DOIUrl":"https://doi.org/10.1029/2025JD043698","url":null,"abstract":"&lt;p&gt;Surface moisture heterogeneity degrades temperature-humidity (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;θ&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $theta $&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;mi&gt;q&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $q$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;) similarity in the atmospheric surface layer, yet the underlying physical mechanisms driving this dissimilarity remain underexplored. This study employs large-eddy simulations coupled with a land-surface model to investigate &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;θ&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $theta $&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;mi&gt;q&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $q$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; similarity in the convective boundary layer (CBL) over surfaces with varying scales of surface moisture heterogeneity. Results reveal that as the heterogeneity scale increases, patch-scale thermally induced circulations develop and interact with cellular turbulent organized structures, significantly altering scalar transport and turbulence dynamics. The patch-scale thermally induced circulations enhance horizontal advection, modify the production and transport of scalar variances, and lead to a disproportionate increase in the standard deviations of temperature (&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;σ&lt;/mi&gt;\u0000 &lt;mi&gt;θ&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${sigma }_{theta }$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;) and humidity (&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;σ&lt;/mi&gt;\u0000 &lt;mi&gt;q&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${sigma }_{q}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;), accompanied by a reduction in &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;θ&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $theta $&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;mi&gt;q&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $q$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; covariance (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mover&gt;\u0000 &lt;mrow&gt;\u0000 ","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 12","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JD043698","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144331901","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":"Underlying Physical Mechanisms in Upward Positive Flashes","authors":"T. Oregel-Chaumont,&nbsp;A. Šunjerga,&nbsp;J. Kasparian,&nbsp;M. Rubinstein,&nbsp;F. Rachidi","doi":"10.1029/2024JD042754","DOIUrl":"https://doi.org/10.1029/2024JD042754","url":null,"abstract":"<p>This study presents the first observation of a mixed mode (MM) of charge transfer during an upward positive flash, which was initiated from the Säntis Tower in Switzerland. High-speed camera footage, along with current and electric field measurements, revealed a downward-propagating recoil leader connecting to the grounded current-carrying plasma channel at a junction height of &lt;1 km above the tip of the tower. This event triggered the “return stroke”-like main pulse associated with Type 1 upward positive flashes, leading us to propose a MM of charge transfer (normally observed in upward negative flashes) as the physical mechanism at play. Furthermore, the observed “Main pulse” shared characteristics with both mixed-mode and M-component-type initial continuous current pulses, challenging existing classification criteria, and supporting the notion of a unique mode of charge transfer with a range of junction length-dependent pulse characteristics, as opposed to two distinct modes. The recoil leader itself was accompanied by a sequence of fast electric field pulses indicative of step-like propagation, also an observational first. These findings contribute to improving our understanding of the mechanisms of charge transfer in upward lightning flashes.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 12","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JD042754","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144336054","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":"Capturing Aerosol-Cloud-Precipitation Interactions: A Physics-Informed Sparse Regression Approach for a Coupled Multiscale System With Time Delay","authors":"Meiling Cheng,&nbsp;Franziska Glassmeier","doi":"10.1029/2024JD043226","DOIUrl":"https://doi.org/10.1029/2024JD043226","url":null,"abstract":"<p>Aerosols exert a net cooling effect on the climate system by reflecting solar radiation, both directly and indirectly through their role in cloud formation, known as aerosol-cloud interactions. The multiscale nature of aerosol-cloud interactions, and especially their mesoscale adjustments and associated challenges for their representation in climate models, makes the aerosol forcing a key uncertainty of climate projections. Here we show that a physics-informed data-driven approach in the form of delay differential equations (DDEs) for coupled cloud-rain dynamics of mesoscale adjustments can combine the interpretability of conceptual models with the quantitative reliability of large-eddy simulations (LESs). Applied to a conceptual model that describes the coupled system as a predator-prey relationship between cloud depth H and cloud droplet number concentration N, the proposed approach faithfully reconstructs the known DDEs when providing information about the microscale physics in the form of an assumed rain-formation function. We further apply our approach to approximate governing DDEs for the complex aerosol-cloud adjustments modeled by LESs. Capturing the governing cloud-rain dynamics as coupled DDEs also requires providing macroscale physics, which translates into separating the rain and nonrain regimes and assumptions about their asymptotic behavior. These governing equations offer a quantitative pathway for predicting the emergent behaviors of aerosol-cloud-precipitation interactions.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 12","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JD043226","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144331957","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":"Subseasonal-To-Seasonal (S2S) Prediction Skill of the Rainfall Diurnal Cycle Over the Maritime Continent and Its MJO Dependence","authors":"Wayne Yuan-Huai Tsai,&nbsp;Naoko Sakaeda,&nbsp;James H. Ruppert","doi":"10.1029/2024JD043102","DOIUrl":"https://doi.org/10.1029/2024JD043102","url":null,"abstract":"<p>The Maritime Continent (MC) is one of the rainiest regions globally, where the diurnal cycle contributes significantly to rainfall variability and can be modulated by the Madden-Julian oscillation (MJO). However, our understanding of diurnal cycle prediction skill and its relevance to the MJO in subseasonal forecast models remains limited. This study evaluates the subseasonal prediction skill of boreal wintertime (from November to January) rainfall diurnal cycle characteristics over the MC using ECMWF and NCEP S2S models and explores the influence of MJO activity on prediction skill. Evaluated diurnal cycle characteristics include the daily mean, diurnal range, and phase. Considerable errors appear in the first day forecast and slowly increase with lead time. Aggregation over longer lead windows can sustain or enhance prediction accuracy. Errors over land are attributed to earlier peaks and larger diurnal ranges than observations, while errors over the sea are typically found along coastlines and in some far ocean regions, such as the tropical northern West Pacific. Furthermore, we stratify the forecasted rainfall diurnal cycle by the MJO phase at forecast initialization to examine the MJO impact on prediction skill in S2S models. The predictions become less skillful when MJO convection reaches the MC because the models greatly underestimate the large diurnal range. This is related to insufficient low-level convergence at the grid scale and inaccuracies in representing the moisture-diurnal cycle relationship in the models. This study contributes to understanding the subseasonal rainfall prediction skill and MJO influence in rainfall prediction over the MC.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 12","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144336079","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":"Marine Volatile Organic Compounds Promote the Chloride Depletion in Sea Salt Aerosols","authors":"Aijing Song,&nbsp;Kun Li,&nbsp;Zhaomin Yang,&nbsp;Narcisse Tsona Tchinda,&nbsp;Lin Du","doi":"10.1029/2025JD043495","DOIUrl":"https://doi.org/10.1029/2025JD043495","url":null,"abstract":"<p>Despite chloride depletion of sea salt aerosols (SSA) is one of the most important phenomena in the coastal atmosphere with significant impacts on air quality and human health, the factors influencing this depletion remain unclear. We analyzed the mole ratio of Cl⁻/Na⁺ to evaluate the effects of coastal atmospheric enriched SO₂ and some marine volatile organic compounds (namely isoprene and dimethyl sulfide (DMS)) on chloride depletion by laboratory experiments. Using ultrahigh performance liquid chromatography/electrospray ionization high-resolution quadrupole time-of-flight mass spectrometer (UPLC/ESI-HR-Q-TOF-MS), the formation of organic chlorinated compounds during chloride depletion of SSA was identified and analyzed to verify marine sources of Cl radicals. Our results show that chloride depletion increased (1.1%–33.7%) with increasing SO₂ concentration (0–400 ppb) due to the production of inorganic acids. This chloride depletion was also enhanced with the addition of isoprene and DMS, with DMS having the greatest effect. In the presence of DMS, the mole ratio of Cl⁻/Na⁺ was 0.721 at an SO₂ concentration of 200 ppb, causing greater chloride depletion than isoprene (0.820). Many organic chlorinated compounds were identified, with CHClSO compounds being identified in experiments in the presence of SO₂. The mass spectrometry results confirm that the activation of chloride ions, another important factor affecting chloride depletion, is essential for the formation of organic chlorinated compounds. These results have implications for model predictions of chloride depletion in polluted coastal areas.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 12","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144336055","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}