Frédéric Chevallier, Adrien Martinez, Zoé Lloret, Sakina Takache, Anne Cozic
{"title":"Offline Atmospheric Transport on a Global Mesh of Hexagons","authors":"Frédéric Chevallier, Adrien Martinez, Zoé Lloret, Sakina Takache, Anne Cozic","doi":"10.1029/2025JD043579","DOIUrl":"https://doi.org/10.1029/2025JD043579","url":null,"abstract":"<p>We present a new version of the offline transport model from the LMDz atmospheric general circulation model. It paves the globe with hexagons and 12 pentagons of similar surface areas rather than with regular longitude-latitude rectangles. It is available in a complete, nonlinear version and in a linearized configuration for use in variational atmospheric inversions. It runs on graphics processing units like the previous version. The previous advection approach and physical parameterizations have been kept while the code has been restructured for better numerical efficiency. The change of mesh was made necessary by the evolution of the parent LMDz model, but the technical and scientific evaluation of the new version with a roughly constant number of cells shows some interesting advantages. This evaluation is based on an 11-year simulation of sulfur hexafluoride and on a 10-year atmospheric inversion assimilating column-averaged dry air mole fractions of carbon dioxide (CO<sub>2</sub>) retrieved from measurements of NASA's second Orbiting Carbon Observatory. As it is used in variational inversion and at 90-km resolution with 79 layers in the vertical, we find that the new offline model is twice as fast. Further, it shows improved interhemispheric transport, some small improvements in terms of inferred (posterior) atmospheric concentrations and small differences in terms of inferred surface fluxes compared to the previous version. These assets allowed it to be commissioned in its 90-km configuration for the operational CO<sub>2</sub> inversions of the European Copernicus Atmosphere Monitoring Service.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 11","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JD043579","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144213768","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":"Constraining Subseasonal Forecast Skill for Spring 2024 Extreme Rainfall in South China by Extratropical Atmospheric Initial Conditions","authors":"Yuhan Yan, Boqi Liu, Congwen Zhu","doi":"10.1029/2025JD043738","DOIUrl":"https://doi.org/10.1029/2025JD043738","url":null,"abstract":"<p>Subseasonal predictability of extreme rainfall events over East Asia is determined by both atmospheric initial conditions and external boundary forcing. However, their feedback processes remain poorly understood during boreal spring. In April–May 2024, South China experienced record-breaking extreme rainfall in the decaying phase of the El Niño event. This extreme event is driven by significant crossing-time scale interactions, which offers a unique opportunity to evaluate their subseasonal predictability in dynamic models. Our results reveal that the western Pacific subtropical high (WPSH) enhanced by El Niño decaying represents the response to slowly varying oceanic forcing. In contrast, quasi-biweekly Rossby wave trains in the extratropics and the eastward-propagating Tibetan Plateau vortex reflect the atmospheric initial conditions. These extratropical atmospheric disturbances reduce the anomalous WPSH via positive advection of anomalous vorticity, thus offsetting the influences of oceanic forcing. Although the anomalous WPSH and above-normal rainfall pattern exhibit high predictability on the monthly timescale, the skillful forecasting of the three extreme rainfall events is less than 1 week. These findings suggest that the extratropical atmospheric disturbances, as initial conditions, can undermine the predictability stemming from tropical air-sea interactions. The forecast skill of the extreme rainfall process in spring is limited by the memory of initial atmospheric states and the intrinsic constraints of weather predictions.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 11","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144214132","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":"Interdecadal Variation and Its Mechanisms of Summer Low Cloud Cover Over the Tibetan Plateau Lake Group","authors":"Ruibo Wang, Xiangde Xu, Xudong Liang, Wenyue Cai","doi":"10.1029/2024JD042864","DOIUrl":"https://doi.org/10.1029/2024JD042864","url":null,"abstract":"<p>This study explores the long-term change and associated mechanisms of low cloud cover (LCC) over the Tibetan Plateau lake group (TPLG). The LCC over the TPLG in the summer of 1979–2020 exhibited a sudden shift of increased interdecadal variation in 1995. The abnormal increases in evaporation and whole-layer specific humidity, and the abnormal convergence of 400 hpa water vapor flux, led to an increase in water vapor over the TPLG, which increased the LCC. The water vapor budget shows that the increase is the most significant along the southern boundary. The cyclonic circulation anomaly in the southwest of the TPLG can transport water vapor to the region. The southerly wind and upward wind anomalies in the south favored water vapor transport through the climbing effect. The water vapor budget at the eastern boundary of the TPLG had the highest correlation coefficient with LCC on the interdecadal scale. The anticyclonic circulation anomaly over Lake Baikal inhibited the outflow of water vapor across the eastern boundary. The anticyclonic circulation was associated with the Rossby wave train. The interdecadal warming of sea surface temperatures in the North Atlantic and Mediterranean-Black Seas played roles in the maintenance of the Rossby waves. The Rossby wave train propagated upward and eastward from the low layer to 200 hpa in the positive anomaly area of the Rossby wave source. The positive anomaly centers of the Rossby wave source were over the North Atlantic, the area around the Black Sea, and the southeastern region of Lake Baikal.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 11","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144197227","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}
Yu Cai, Yao Xiao, Xiaoyi Shen, Haili Li, Zifei Wang, Jingjing Wang, Chang-Qing Ke
{"title":"Current and Projected Changes in Lake Ice Phenology on the Tibetan Plateau: Impacts of Climate Change and Lake Expansion","authors":"Yu Cai, Yao Xiao, Xiaoyi Shen, Haili Li, Zifei Wang, Jingjing Wang, Chang-Qing Ke","doi":"10.1029/2025JD043623","DOIUrl":"https://doi.org/10.1029/2025JD043623","url":null,"abstract":"<p>In recent decades, the Tibetan Plateau has experienced a warmer and wetter climate. As a robust climate indicator, lake ice phenology responds sensitively to these changes. Beyond climate conditions, lake ice is also influenced by lake properties, which have also been changing rapidly. However, their impact on lake ice has been understudied due to limited data. Therefore, we used Advanced Microwave Scanning Radiometer 2 brightness temperature data and daily air temperature data to obtain the ice phenology for 182 lakes on the Tibetan Plateau from September 2012 to August 2022. Using this new data set, we examined the impacts of climate change and lake expansion on lake ice dynamics and their future changes. Our findings indicated that lake ice phenology on the Tibetan Plateau was strongly influenced by multiple factors. Freeze-up dates were primarily affected by lake properties such as latitude, volume, and area, whereas break-up dates were dominated by air temperature. Using random forest regression, we projected future declines in lake ice under the SSP126, SSP245, and SSP585 scenarios. Additionally, lake expansion could further delay freeze-up dates. By the end of this century, freeze-up dates are expected to be delayed by 3–11 days, while break-up dates could advance by 2–20 days, depending on the climate scenario. These findings highlight the urgent need to mitigate climate change to reduce lake ice loss on the Tibetan Plateau.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 11","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144197259","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}
Minmin Sun, Wenying Jiang, Jie Lin, Xiaofang Huang, Xiaoxiao Yang, Shiling Yang
{"title":"Interhemispheric Temperature Gradient Was the Primary Driver of Indian Monsoon Intensity Since the Last Glacial Maximum","authors":"Minmin Sun, Wenying Jiang, Jie Lin, Xiaofang Huang, Xiaoxiao Yang, Shiling Yang","doi":"10.1029/2024JD043119","DOIUrl":"https://doi.org/10.1029/2024JD043119","url":null,"abstract":"<p>Knowledge of glacial-interglacial changes in the Indian summer monsoon (ISM) can provide insights into future hydrological changes in the monsoon region. We analyzed the grain size, branched glycerol dialkyl glycerol tetraethers (brGDGTs), and leaf wax hydrogen isotopes (δD<sub>wax</sub>) of sediments from Lake Tianchi in the ISM region, to reconstruct the temperature and monsoon history for the past 23 kyr. The results reveal a notable negative correlation between the abundance of brGDGT-IIIa and grain size, indicating the non-negligible influence of soil-derived brGDGTs on temperature. Using the grain size-brGDGT-IIIa relationship, we assessed the contribution of soil-derived brGDGTs and corrected the temperature accordingly. The results reveal a ∼6°C warming from the Last Glacial Maximum (LGM; 23–20 kyr) to the mid-Holocene (∼8–6 kyr), punctuated by several millennial-scale events, including Heinrich event 1 (H1; 16.5–15 kyr), the Bølling-Allerød (B/A; 15–12.8 kyr), and the Younger Dryas (YD; ∼12.8–11 kyr), with H1 being the coldest interval. The δD<sub>wax</sub> records show that H1 was the driest interval, with a drier LGM and YD and a wet B/A and early- to mid-Holocene. Furthermore, the δD<sub>wax</sub> records display a pattern of variation similar to the interhemispheric temperature gradient, indicating that the intensity of this gradient is the primary factor controlling the ISM precipitation. Given the significant influence of Antarctic ice on the interhemispheric temperature gradient, the anticipated loss of half of the Antarctic sea ice by 2100 would lead to the southward shift of the Intertropical Convergence Zone and associated drought in the ISM region.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 11","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206747","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":"Photochemical Aging of PM2.5 Nitroaromatic Compounds From Solid Fuel Combustion Enhanced Light Absorption and Oxidation Potential","authors":"Shasha Huang, Zhenxing Shen, Gezi Bai, Leiming Zhang, Diwei Wang, Cailan Li, Honghao Zheng, Hongmei Xu, Ying Zhang","doi":"10.1029/2025JD043471","DOIUrl":"https://doi.org/10.1029/2025JD043471","url":null,"abstract":"<p>This study investigates primary emissions and photochemical aging evolution mechanisms of PM<sub>2.5</sub> Nitroaromatic compounds (NACs) released from solid fuels through conducting field combustion experiments. The emission factors (EFs) of NACs primary emissions are much higher from biomass burning (BB) than coal combustion (CC). The EFs of measured NACs species mostly increased during the aging process except some species in CC. Photochemical aging significantly enhanced the absorbance of ∑NACs, but through different mechanisms between BB and CC. In BB, increasing production of 4-nitrocatechol (4NC), 4-nitroguaiacol (4NG), and 4-methyl-5-nitrocatechol (4M5NC) through nitrogen addition reactions during aging process enhanced the NACs light absorption. In CC, increasing 4NC and 4-methyl-2,6-dinitrophenol from nitrogen addition reactions as well as indirect photolysis of 4NG and 4M5NC with ·OH to form organic intermediates both increase light absorption. Furthermore, 4M5NC and 4NG enhanced PM<sub>2.5</sub> oxidation potential substantially through auto-biotoxicity and generation of facilitating <sup>1</sup>O<sub>2</sub> in BB and decomposing into nitro-quinones in CC.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 11","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144197258","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":"Homogenization of Surface Wind Speed Over Global Land From 1973 to 2022","authors":"Zhengtai Zhang, Kaicun Wang","doi":"10.1029/2024JD042939","DOIUrl":"https://doi.org/10.1029/2024JD042939","url":null,"abstract":"<p>Although homogenization has been widely applied to historical records of surface air temperature, the homogenization of surface wind speed (SWS) data remains limited likely because the SWS is more sensitive to local environment, making it difficult to find suitable reference from nearby stations. To address this issue, we have developed a method for calculating geostrophic wind speed, which has been used as the reference to perform homogeneity detection and adjustment for the SWS at stations in China. Here, the method is applied to homogenize annual mean SWS from more than 3,600 stations over global land from 1973 to 2022. Although further confirmation from the metadata is required, the homogenization significantly reduces statistical inhomogeneity (<i>p</i> = 0.01) in the raw SWS. The results show that about 35% of the global stations exhibit inhomogeneities in SWS, and this phenomenon is more pronounced over North America and Europe. The homogenization has a minimal impact on the global average trend of SWS, but has major impacts on regional trends, especially in Europe, Asia, and Oceania. Compared with the raw SWS, the trend of homogenized SWS from 1973 to 2022 changed from −0.052 to −0.027 m s<sup>−1</sup> per decade in Europe, and from −0.066 to −0.033 m s<sup>−1</sup> per decade in Asia. In Oceania, the homogenization decreases the SWS trend from 0.24 to 0.081 m s<sup>−1</sup> per decade. This study emphasizes the importance of considering the homogeneity of SWS data when analyzing its changes, particularly at regional scales.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 11","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144190672","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}
C. Mignani, T. C. J. Hill, M. Nieto-Caballero, K. R. Barry, N. C. Bryan, P. J. Marinescu, B. Dolan, A. P. Sullivan, M. Hernandez, A. Bosco-Lauth, S. C. van den Heever, E. A. Stone, L. D. Grant, R. J. Perkins, P. J. DeMott, S. M. Kreidenweis
{"title":"Ice-Nucleating Particles Are Emitted by Raindrop Impact","authors":"C. Mignani, T. C. J. Hill, M. Nieto-Caballero, K. R. Barry, N. C. Bryan, P. J. Marinescu, B. Dolan, A. P. Sullivan, M. Hernandez, A. Bosco-Lauth, S. C. van den Heever, E. A. Stone, L. D. Grant, R. J. Perkins, P. J. DeMott, S. M. Kreidenweis","doi":"10.1029/2024JD042584","DOIUrl":"https://doi.org/10.1029/2024JD042584","url":null,"abstract":"<p>Ice-nucleating particles (INPs) play a key role in ice formation and cloud microphysics and thus significantly impact the water cycle and the climate. However, our understanding of atmospheric INPs, particularly their sources, emissions, and spatiotemporal variability, is incomplete. While the enhancement of atmospheric INP concentrations with rainfall has been previously shown, a mechanistic understanding of the process is lacking. Here, we link detailed precipitation observations with near-surface atmospheric INP concentrations at a semiarid grassland site in Colorado. Considering the during-precipitation air samples, INP concentrations positively correlate with cumulative rainfall kinetic energy and amount, suggesting that INP aerosolization is induced by raindrop and hailstone impact. By additionally analyzing the INP content of precipitation water, terrestrial source samples, and heat-treated samples, we demonstrate that local plants are the most plausible source of rain-induced INPs during a precipitation event. Should INPs aerosolized by precipitation rise to cloud height, they could influence cloud ice fraction and initiate precipitation resulting in an aerosol-cloud-precipitation feedback.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 11","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JD042584","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144185871","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}
Huawei Pi, John T. Abatzoglou, Nicholas P. Webb, Sisi Li
{"title":"Dust Event Variations Between China's Different Climate Zones","authors":"Huawei Pi, John T. Abatzoglou, Nicholas P. Webb, Sisi Li","doi":"10.1029/2024JD042230","DOIUrl":"https://doi.org/10.1029/2024JD042230","url":null,"abstract":"<p>Dust weather may occur and be frequent in some nondry climate zones due to extreme natural climatic or disturbance events and human activities. In this study, the spatiotemporal characteristics of dust events at 1941 meteorological stations in China, encompassing 13 Köppen-Geiger climate zones, were investigated. Floating dust frequency (FDF), blowing dust frequency (BDF), dust storm frequency, and related meteorological data were analyzed to assess dust activity from 1960 to 2020. Dust events decreased significantly from 1960 to 2020, and the BDF had the greatest rate (−0.13 d y<sup>−1</sup>), while the FDF had the greatest mean frequency (4.349 d y<sup>−1</sup>). The frequency of dust events (FDE) was two orders of magnitude greater in the cold desert climate when compared with the other climate zones, although the annual wind speed was not always greater. The FDE in the nondry climate zones ranged from 0.005 d y<sup>−1</sup> in the Aw (tropical savanna climate) to 12.34 d y<sup>−1</sup> in the ET (polar tundra). As a nondry climate zone, the ET had more frequent dust activity than some of the other dry climate zones. Dust events were generally most active in March, April, and May. However, the most active month could occur as early as January (e.g., 1963) and as late as June (e.g., in 1967). Results show that dust activity was associated with meteorological parameters in every climate zone and that the impact of human activities (e.g., overcultivation) on dust activity was non-negligible. Nonarid dust activities may affect integrated region climate patterns and carbon cycle modeling.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 11","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144185869","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}
Larry Guan, Xinyue Wang, Xun Jiang, Liming Li, King-Fai Li
{"title":"Impacts of El Niño-Southern Oscillation on Earth's Radiant Energy Budget","authors":"Larry Guan, Xinyue Wang, Xun Jiang, Liming Li, King-Fai Li","doi":"10.1029/2024JD042611","DOIUrl":"https://doi.org/10.1029/2024JD042611","url":null,"abstract":"<p>We investigate the impact of the El Niño-Southern Oscillation (ENSO) (i.e., El Niño and La Niña events) on the radiant energy budget (REB) of our home planet—Earth. Using the most recent and extensive datasets available from CERES energy balanced and filled (CERES-EBAF), we confirm and extend upon prior works. Particularly, we compare the mean El Niño/La Niña radiance anomalies in the tropics to the mean normal state over 2001–2022. Modifications to the energy budget's components (absorbed solar power and emitted thermal power) exceed 10% within the western and central Pacific—up to 20% for net power. Principal component analysis results further suggest that ENSO contributes approximately 34.0%, 44.9%, and 21.3% of the total variance in absorbed power, emitted power, and net power, respectively. Finally, a comparative study between observational data and the numerical simulations suggests that current climate models cannot quantitatively capture the signals of ENSO in Earth's REB even though some of them can reproduce dominant features. Our investigations based on the comprehensive observational datasets for Earth can serve as a foundation for exploring the impacts of large-scale atmospheric and climate processes on the REBs of other planets.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 11","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144185870","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}