Geophysical Research Letters最新文献

{"title":"Mechanisms Linking Stratospheric Gravity Wave Activity to Hurricane Intensification: Insights From Model Simulation of Hurricane Joaquin","authors":"X. Wu,&nbsp;L. Hoffmann,&nbsp;C. J. Wright,&nbsp;N. P. Hindley,&nbsp;M. J. Alexander,&nbsp;X. Wang,&nbsp;B. Chen,&nbsp;Y. Wang,&nbsp;M. Li","doi":"10.1029/2024GL113531","DOIUrl":"10.1029/2024GL113531","url":null,"abstract":"<p>Previous studies based on satellite observations and model simulations have revealed a significant correlation between intense stratospheric gravity wave (GW) activity and hurricane intensification. This research further investigated the underlying mechanism of this correlation by analyzing the properties and propagation characteristics of stratospheric GWs excited by Hurricane Joaquin based on a Weather Research and Forecasting model simulation. By employing the 3-D Stockwell wave analysis method, we found that GWs excited during hurricane intensification display relatively higher intrinsic frequencies, shorter horizontal wavelengths, and longer vertical wavelengths than during weakening. Analysis of these GWs' propagation using the GROGRAT ray-tracing model revealed that they can reach the middle stratosphere rapidly within 20 min. This quick propagation enabled the observation of intense stratospheric GWs before the hurricane reached its peak intensity, offering a potential indicator for hurricane intensification. These findings strengthened the basis for considering stratospheric GW activity as a proxy for hurricane intensification under specific conditions.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 10","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL113531","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144130665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Samudra: An AI Global Ocean Emulator for Climate","authors":"Surya Dheeshjith,&nbsp;Adam Subel,&nbsp;Alistair Adcroft,&nbsp;Julius Busecke,&nbsp;Carlos Fernandez-Granda,&nbsp;Shubham Gupta,&nbsp;Laure Zanna","doi":"10.1029/2024GL114318","DOIUrl":"10.1029/2024GL114318","url":null,"abstract":"<p>AI emulators for forecasting have emerged as powerful tools that can outperform conventional numerical predictions. The next frontier is to build emulators for long climate simulations with skill across a range of spatiotemporal scales, a particularly important goal for the ocean. Our work builds a skillful global emulator of the ocean component of a state-of-the-art climate model. We emulate key ocean variables, sea surface height, horizontal velocities, temperature, and salinity, across their full depth. We use a modified ConvNeXt UNet architecture trained on multi-depth levels of ocean data. We show that the ocean emulator—<i>Samudra</i>—which exhibits no drift relative to the truth, can reproduce the depth structure of ocean variables and their interannual variability. Samudra is stable for centuries and 150 times faster than the original ocean model. Samudra struggles to capture the correct magnitude of the forcing trends and simultaneously remain stable, requiring further work.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 10","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL114318","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144130667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Coastal Erosion as a Major Sediment Source in the Inner Gulf of Thailand: Implications for Carbon Dynamics in Tropical Coastal Ocean Systems","authors":"Bingbing Wei,&nbsp;Stephanie Kusch,&nbsp;Till J. J. Hanebuth,&nbsp;Limin Hu,&nbsp;Miao Fan,&nbsp;Guodong Jia,&nbsp;Gesine Mollenhauer,&nbsp;Moritz Holtappels","doi":"10.1029/2025GL115606","DOIUrl":"10.1029/2025GL115606","url":null,"abstract":"<p>Coastal erosion is an increasingly dominant sediment source in marginal seas, particularly in low-lying areas affected by deltaic subsidence and sediment deficits from upstream water management. However, its role in sediment and organic carbon (OC) dynamics remains to be estimated. Our analyses of the inner Gulf of Thailand (IGoT) revealed that riverine sediment fluxes decreased from 6.6 to 5.4 Mt/yr after 1975, while sediment accumulation within the IGoT increased from 20.8 to 29.5 Mt/yr. The observed trend indicates major sediment contributions from coastal erosion, particularly from mangrove deposits. This process destabilizes coastal ecosystems and accelerates OC decomposition, that is, a low burial efficiency (16.8 ± 5.5%) leads to CO₂ release. Extrapolating these findings globally, mangrove loss could release ∼175 Tg/yr CO₂. As coastal erosion intensifies under sea-level rise and human land-use practices, preserving coastal ecosystems is critical for mitigating blue carbon loss and maintaining coastal stability and resilience.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 10","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GL115606","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144130664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Glacial Methane Hydrate Dissociation in the South China Sea Margin During the Oligocene","authors":"Fenghao Liu,&nbsp;Enqing Huang,&nbsp;Xiaobo Jin,&nbsp;Jun Tian","doi":"10.1029/2024GL114439","DOIUrl":"https://doi.org/10.1029/2024GL114439","url":null,"abstract":"<p>Methane hydrate dissociation along continental margins has been widely associated with global carbon cycle perturbations and climate changes. However, the relationship between hydrate dynamics, carbon cycle disturbances, and climate variations remains unclear. Here, we report eleven anomalously depleted carbon isotope excursions in benthic foraminifera, along with increased coccolith recrystallization, suggesting episodic methane release from the northern South China Sea during the Oligocene. These abnormal patterns were generally coupled with benthic oxygen isotope maxima, indicating that hydrate destabilization was triggered by ice sheet expansion and sea-level decline during the Antarctic glaciations. This contrasts with the majority of previous studies, which have typically linked methane-sourced carbon emissions to global warming throughout Earth's history.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 10","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL114439","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144118114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"True Polar Wander Driven by Artificial Water Impoundment: 1835–2011","authors":"N. Valencic,&nbsp;E. Speiser,&nbsp;E. Doi,&nbsp;E. T. Lee,&nbsp;B. Ford,&nbsp;A. Hatzius,&nbsp;D. Komaravalli,&nbsp;B. Erdmann,&nbsp;W. Hawley,&nbsp;J. X. Mitrovica","doi":"10.1029/2025GL115468","DOIUrl":"https://doi.org/10.1029/2025GL115468","url":null,"abstract":"<p>Artificial water impoundment contributed significantly to global mean sea level change during the 20th century and is included in recent studies of the budget of 20th century true polar wander (TPW). We adopt a recent global database of water impoundment that accounts for 72% of an integrated global volume estimate and compute the associated TPW path from 1835 to 2011 CE. We find a highly non-monotonic pole path, with an integrated path length of 113.4 cm, a net displacement of 20.5 cm in the direction 103.4°E from 1835 to 1954 CE and 57.1 cm in the direction −117.5°E from 1954 to 2011. Across the first half of the 20th century, the mean rate of TPW was 0.30 cm/yr, while in the second half of the century it was 0.95 cm/yr. Finally, we demonstrate that the 28% of the total global water impoundment missing in our database likely had a negligible impact on polar motion.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 10","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GL115468","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144118109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Does the Dayside Equatorial Ionospheric Electric Field Respond to Isolated Substorms?","authors":"M. Hayashi,&nbsp;A. Yoshikawa,&nbsp;S. Ohtani","doi":"10.1029/2025GL115227","DOIUrl":"https://doi.org/10.1029/2025GL115227","url":null,"abstract":"<p>Substorms are known to induce global magnetosphere-ionosphere coupling. However, the specific response of the dayside ionospheric electric field and its influence on the equatorial electrojet (EEJ) remain controversial. This study investigates the electromagnetic field response in the dayside equatorial region during isolated substorms using ground magnetic field data. Statistical analysis revealed that the H component decreased at equatorial and low-latitude stations during isolated substorms. These decreases were of similar magnitude on average, indicating that significant changes in the EEJ caused by penetrating electric fields were not observed. However, individual events showed slight positive and negative variations. These results suggest that substorm-associated electric fields can reach equatorial regions, but additional conditions determine the positive and negative variations. This finding provides new insights into the spatial extent of substorm-induced electric fields.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 10","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GL115227","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144118110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 Subduction Fluids and Fractional Crystallization on the Magnetic Minerals Formation in the Back-Arc Basin","authors":"Jie Xu,&nbsp;Zhaoxia Jiang,&nbsp;Xia Zhang,&nbsp;Sangzhong Li,&nbsp;Xiyao Li,&nbsp;Long Chen,&nbsp;Haonan Song,&nbsp;Yuying Chen,&nbsp;Yuzhen Zhang,&nbsp;Zehua Guo,&nbsp;Kun Guo,&nbsp;Qingsong Liu","doi":"10.1029/2025GL115006","DOIUrl":"https://doi.org/10.1029/2025GL115006","url":null,"abstract":"<p>(Titano)magnetite is the major magnetic carrier in igneous rocks, whether it can decode the influence of subduction fluids and fractional crystallization characteristics in back-arc basins is unclear. Here, we performed petrographic and magnetic analyses on volcanic samples from the Okinawa Trough, with titanomagnetite as the dominant magnetic mineral. Results show that the Curie temperature of Ti-rich titanomagnetites (T_{c TM-R}) not only has the potential to identify the influence of subduction fluids in back-arc basins but also can be used to differentiate basalts and basaltic andesites that have been formed in different geologic settings. Additionally, the magnetic domain state ranges from single domain to multi-domain as the fractional crystallization proceeds. Our study illustrates that magnetic properties of titanomagnetite are potential tracers for subduction fluids and fractional crystallization, which is of referential significance for research on relatively scarce samples from subduction zones and even extraterrestrial bodies.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 10","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GL115006","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144118113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Cross-Scale Interactions Between ULF Waves, VLF Waves, and Electrons","authors":"Xing-Yu Li,&nbsp;Qiu-Gang Zong,&nbsp;Shan Wang,&nbsp;Xu-Zhi Zhou,&nbsp;Chao Yue,&nbsp;Li Li,&nbsp;Zhi-Yang Liu,&nbsp;Yong-Fu Wang,&nbsp;Ze-Fan Yin,&nbsp;Yi-Xin Sun,&nbsp;Yi-Xin Hao,&nbsp;Craig Pollock,&nbsp;Christopher T. Russell,&nbsp;Robert E. Ergun,&nbsp;Per-Arne Lindqvist","doi":"10.1029/2025GL115095","DOIUrl":"https://doi.org/10.1029/2025GL115095","url":null,"abstract":"<p>Wave-particle interactions are essential for energy transport in the magnetosphere. In this study, we investigated an event during which electrons interact simultaneously with waves in different scales, using data from the Magnetospheric Multiscale mission. At the macroscale (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 <mn>1</mn>\u0000 <msup>\u0000 <mn>0</mn>\u0000 <mn>5</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${sim} 1{0}^{5}$</annotation>\u0000 </semantics></math> km), drift resonance between ultra-low frequency (ULF) waves and 70–300 keV electrons is observed. At the microscale (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 <mn>1</mn>\u0000 <msup>\u0000 <mn>0</mn>\u0000 <mn>0</mn>\u0000 </msup>\u0000 <mo>−</mo>\u0000 <mn>1</mn>\u0000 <msup>\u0000 <mn>0</mn>\u0000 <mn>1</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${sim} 1{0}^{0}-1{0}^{1}$</annotation>\u0000 </semantics></math> km), lower-band chorus waves and electron cyclotron harmonic (ECH) waves are alternately generated, showing signatures of modulation by ULF waves. We found that compressional ULF waves affect the temperature anisotropy of 1–10 keV electrons, thereby periodically exciting chorus waves. Through linear instability analysis, we propose that ULF waves modulate ECH wave emissions by regulating the gradient of electron phase space density at the edge of the loss cone. Our results enhance the understanding of cross-scale wave-particle interactions, highlighting their importance in magnetospheric dynamics.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 10","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GL115095","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144108738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Performance Assessment of Surface Water and Ocean Topography (SWOT) Mission for WSE Measurement Across India","authors":"Girish Patidar,&nbsp;J. Indu,&nbsp;Subhankar Karmakar","doi":"10.1029/2025GL115804","DOIUrl":"https://doi.org/10.1029/2025GL115804","url":null,"abstract":"<p>The Surface Water and Ocean Topography (SWOT) mission, launched in December 2022, is the first wide-swath altimetry mission designed to improve our understanding of surface water dynamics through high-resolution water surface elevation (WSE) and extent measurements. This study presents the first-hand validation of SWOT WSE data from April 2023 to December 2024 across 419 stations in India, analyzing 14,892 SWOT WSE observations. Our findings indicate that SWOT performs well for rivers wider than 100 m, with a Spearman's correlation (<i>ρ</i>_s) exceeding 0.88 for the 68th percent of stations with a relative error (RE) in WSE of 18 cm. Even for narrower rivers, SWOT achieves accuracies exceeding expectations (RE of 25.78 cm). Over reservoirs, SWOT demonstrates strong performance, with RE values of 10.80 cm (node product) and 13.64 cm (lake product), while maintaining <i>ρ</i>_s above 0.65 for all reservoirs analyzed, highlighting SWOT's robust potential for monitoring diverse water bodies in India.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 10","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GL115804","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144108775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Deep Learning Improves Prediction of the Boreal Summer Intraseasonal Oscillation Using Predictive Source Analysis","authors":"Yuki Maeda,&nbsp;Masaki Satoh","doi":"10.1029/2024GL114477","DOIUrl":"https://doi.org/10.1029/2024GL114477","url":null,"abstract":"<p>The Boreal Summer Intraseasonal Oscillation (BSISO) is a prominent tropical intraseasonal variability during summer. It propagates northeastward from the northern Indian Ocean to the western North Pacific and has a more complex structure than the winter-dominant Madden-Julian Oscillation, which makes its prediction challenging. We propose a real-time prediction framework for the bimodal intraseasonal oscillation index using deep learning (DL) models for 1-month forecasting. We show that the BSISO prediction skill (Cor = 0.6) reaches about 29 days during June to August, outperforming existing numerical models. Using explainable artificial intelligence, we quantitatively evaluated DL model prediction sources. Precipitable water (PW), sea surface temperature (SST), and 200 hPa zonal wind significantly contributed to forecasts over 15 days. For 15–20-day predictions, the heatmap-based analysis indicated that PW mainly contributes to eastward propagation over the maritime continent. The Indo-Pacific SST warm pool also exhibits large predictive contributions, suggesting a role in triggering northward propagation.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 10","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL114477","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144118121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}