Geophysical Research Letters最新文献

{"title":"Low Geomagnetic Field Intensity in Southern China 6,000 Years Ago","authors":"Xin Luo,&nbsp;Jiabo Liu,&nbsp;Huapei Wang,&nbsp;Maximilian Schanner,&nbsp;Yuan Zhang,&nbsp;Peng Xie,&nbsp;Jigen Tang,&nbsp;Peng Han,&nbsp;Quan Li,&nbsp;Fei Han,&nbsp;Xiaowei Chen,&nbsp;Chen Wen,&nbsp;Wen Zhong,&nbsp;Yufan Hu,&nbsp;Qingsong Liu","doi":"10.1029/2024GL113552","DOIUrl":"https://doi.org/10.1029/2024GL113552","url":null,"abstract":"<p>The West Pacific Anomaly (WPA), a low geomagnetic field anomaly observed in the 16th to 18th centuries, represents a recently recognized and complex feature of Earth's magnetic field. However, the history of the WPA is still uncertain due to a scarcity of paleointensity data in Southeast Asia. Here, we conducted archeointensity analyses on pottery shards from the Xiajiaoshan site in southern China, dated to 4107 ± 123 BCE. Using Thellier–Coe and Repeated Thellier-Series Experiment methods, we obtained high-fidelity paleointensities ranging from 14.1 to 26.4 μT (20.7 ± 4.4 μT). These values are significantly lower than surrounding archeointensity data. We incorporated this new data into ArchKalmag14k paleomagnetic field model, which shows the presence of a geomagnetic field low-intensity anomaly in Southeast Asia around 6,000 years ago. Our study provides the first absolute paleointensity data for low-latitude East Asia at that time, suggesting that the WPA may have recurred approximately 6,000 years ago.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 9","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL113552","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143919564","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":"Weakened Atlantic Meridional Overturning Circulation Contributes to Opposite Responses of ENSO and the Atlantic Niño/Niña to Greenhouse Warming","authors":"Yun Yang,&nbsp;Lixin Wu,&nbsp;Wenju Cai,&nbsp;Xi Cheng,&nbsp;Xinyue Mei,&nbsp;Fan Jia,&nbsp;Shujun Li,&nbsp;Tao Geng,&nbsp;Yuhu Chen,&nbsp;Hong Wang","doi":"10.1029/2025GL114761","DOIUrl":"https://doi.org/10.1029/2025GL114761","url":null,"abstract":"<p>The Pacific El Niño-Southern Oscillation and the Atlantic Niño/Niña change oppositely in the 21st century. Here, we find the weakened Atlantic Meridional Overturning Circulation (AMOC) plays a key role. Via reducing the equatorial Pacific trades and the Atlantic poleward heat transport, the weakened AMOC contributes to, at surface, a similar Niño-like sea surface temperature (SST) warming and a strengthened atmospheric stratification in both basins, while, at subsurface, a western Pacific cooling in comparison to an intense Atlantic warming. The distinct subsurface changes induce strengthened Pacific oceanic stratification to enhance Bjerknes feedback, in contrast to an insignificant change in the Atlantic. Moreover, the similar surface changes exert different impacts, with a strengthened atmospheric stratification suppressing the Atlantic Bjerknes feedback, an influence offset in the Pacific by an eastward shift of deep convection due to Niño-like SST warming. Such offset is absent in the Atlantic owing to the northern-hemisphere-located deep convection.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 9","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GL114761","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143919652","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":"Predictions of Auroral Electron Precipitation and Joule Heating at Uranus","authors":"Daniel J. Gershman,&nbsp;George Clark","doi":"10.1029/2024GL114470","DOIUrl":"https://doi.org/10.1029/2024GL114470","url":null,"abstract":"<p>The precipitation of electrons and Joule heating are key processes through which energy is transferred from Uranus' magnetosphere to its upper atmosphere. These processes drive atmospheric ionization, thermospheric heating, and auroral emission at Uranus. Here we scale measurements at Earth, Saturn, and Jupiter, with relevant Voyager 2 observations to estimate the properties of magnetospheric energy input at Uranus. We find that the acceleration of electrons between the magnetosphere and thermosphere is predicted to be Earth-like, but with significantly lower overall energy flux and field aligned currents due to Uranus' sparser magnetosphere. In addition, we estimate that the height-integrated Joule heating rates at Uranus could reach ∼1 mW/m², levels that would produce significant thermospheric heating.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 9","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL114470","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143919654","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":"Remote Sensing of River Discharge Based on Critical Flow Theory","authors":"Carl J. Legleiter,&nbsp;Gordon Grant,&nbsp;Inhyeok Bae,&nbsp;Becky Fasth,&nbsp;Elowyn Yager,&nbsp;Daniel C. White,&nbsp;Laura Hempel,&nbsp;Merritt E. Harlan,&nbsp;Christina Leonard,&nbsp;Robert Dudley","doi":"10.1029/2025GL114851","DOIUrl":"https://doi.org/10.1029/2025GL114851","url":null,"abstract":"<p>Critical flow theory provides a physical foundation for inferring discharge from measurements of wavelength and channel width made from images. In rivers with hydraulically steep local slopes greater than <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 </mrow>\u0000 <annotation> ${sim} $</annotation>\u0000 </semantics></math>0.01, flow velocities are high and the Froude number <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>F</mi>\u0000 <mi>r</mi>\u0000 </mrow>\u0000 <annotation> $Fr$</annotation>\u0000 </semantics></math> (ratio of inertial to gravitational forces) can approach 1.0 (critical flow) or greater. Under these conditions, undular hydraulic jumps (UHJ's) can form as standing wave trains at slope transitions or constrictions. The presence of UHJ's indicates that mean <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>F</mi>\u0000 <mi>r</mi>\u0000 <mo>≈</mo>\u0000 <mn>1</mn>\u0000 </mrow>\u0000 <annotation> $Frapprox 1$</annotation>\u0000 </semantics></math>, implying that the velocity and depth of the flow and the spacing of the waves are uniquely related to one another. Discharges estimated from 82 Google Earth images agreed closely with discharges recorded at gaging stations (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>R</mi>\u0000 <mn>2</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${R}^{2}$</annotation>\u0000 </semantics></math> = 0.98), with a mean bias of 1% <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>±</mo>\u0000 </mrow>\u0000 <annotation> $pm $</annotation>\u0000 </semantics></math> 11%. This approach could provide reliable discharge information in many fluvial environments where critical flow occurs, which tend to be underrepresented in gage networks.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 9","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GL114851","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143919562","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":"Predicting Melt Pond Coverage on Arctic Sea Ice From Pre-Melt Surface Topography","authors":"Niels Fuchs,&nbsp;Gerit Birnbaum,&nbsp;Niklas Neckel,&nbsp;Torbjoern Kagel,&nbsp;Melinda Webster,&nbsp;Andreas Wernecke","doi":"10.1029/2025GL115033","DOIUrl":"https://doi.org/10.1029/2025GL115033","url":null,"abstract":"<p>Sea-ice melt ponds form in the depressions of pre-melt surface topography, a process widely accepted yet lacking larger-scale evaluation through explicit comparisons. During MOSAiC, we collected multi-dimensional aerial data to examine the relationship between pre-melt surface topography and melt pond evolution across an entire Arctic ice floe. Using hydrological models, we analyze the correlation between potential meltwater accumulation areas identified in winter and spring topographies, available meltwater, and observed pond coverage. Our findings demonstrate a strong connection, revealing a 72% accuracy in matching low areas to melt ponds, with 98% of basins deeper than 0.5 m transforming into ponds. Incorporating assumptions regarding meltwater availability improve predictions of melt pond fraction and highlight key factors driving extensive lateral runoff networks on the floe. No significant differences are observed between first- and second-year ice. This study provides valuable ground truth for future modeling and measurements of pond formation.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 9","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GL115033","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143919653","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":"Developing a Lagrangian Frame Transformation on Satellite Data to Study Cloud Microphysical Transitions in Arctic Marine Cold Air Outbreaks","authors":"Hannah Seppala,&nbsp;Zhibo Zhang,&nbsp;Xue Zheng","doi":"10.1029/2025GL115637","DOIUrl":"https://doi.org/10.1029/2025GL115637","url":null,"abstract":"<p>Arctic marine cold air outbreaks (CAOs) generate distinct and dynamic cloud regimes due to intense air-sea interactions. To understand the temporal evolution of CAO cloud properties and compare different CAO events, a Lagrangian perspective is particularly useful. We developed a novel technique that enables the conversion of inherently Eulerian satellite data into a Lagrangian framework, combining the broad spatiotemporal coverage of satellite observations with the advantages of Lagrangian tracking. This technique was applied to eight CAO cases associated with a recent field campaign. Our results reveal a striking contrast among the cases in terms of cloud-top phase transitions, providing new insights into the evolution of CAO cloud properties.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 9","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GL115637","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143919563","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":"Distinct Intraseasonal Oscillation Modes Over the Tropical Indo-Pacific Oceans","authors":"Yiran Li,&nbsp;Haibo Hu,&nbsp;Fei Liu,&nbsp;Matthew Patterson,&nbsp;Xiu-Qun Yang,&nbsp;Kecheng Lu,&nbsp;Kefeng Mao,&nbsp;Ziyi Wang,&nbsp;Rongrong Wang","doi":"10.1029/2024GL113263","DOIUrl":"https://doi.org/10.1029/2024GL113263","url":null,"abstract":"<p>In boreal winter, the Madden-Julian Oscillation (MJO) is the dominant mode of tropical intraseasonal oscillation (ISO), which bridges weather and climate. In addition to the dominant eastward propagating MJO mode, this study identifies the existence of the westward propagating and stationary oscillating ISO modes according to the spatio-temporal evolution of large-scale precipitation. At the pentad timescale, each ISO mode tends to suppress the occurrence of the other two. The diagnostic of column-integrated moist static energy (MSE) tendency anomalies reveals the dominant contribution from horizontal MSE advection to each ISO mode. Synthesis results indicate that vertical zonal wind shear anomalies exhibit opposite distributions between the propagating and stationary oscillating ISO events over the tropical Indo-Pacific Oceans. Subsequent simulations prove that the easterly (westerly) wind shear anomalies could suppress the eastward (westward) propagating convection of the ISO, thus favoring a stationary oscillating ISO.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 9","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL113263","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143919655","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":"ENSO-Driven Seasonal Variability in Near-Surface Wind Speed and Wind Power Potential Across China","authors":"Zhi-Bo Li,&nbsp;Ming Sun,&nbsp;Cheng Shen,&nbsp;Deliang Chen","doi":"10.1029/2025GL115537","DOIUrl":"https://doi.org/10.1029/2025GL115537","url":null,"abstract":"<p>Seasonal variations in near-surface wind speed (NSWS) significantly impact wind energy production, yet the role of the El Niño–Southern Oscillation (ENSO) in shaping these variations remains insufficiently explored. This study investigates ENSO-driven seasonal NSWS variability across China and their implications for wind power density (WPD). We demonstrate that ENSO exerts strongly season-dependent impacts on WPD in subregions, spanning the ENSO-developing summer to the decaying summer. During these active ENSO phases, 15%–50% of stations within that regions exhibit WPD anomalies exceeding ±10% relative to their seasonal climatology in response to a 1°C sea surface temperature change in the central-eastern Pacific during the ENSO peak winter. Furthermore, 850 hPa wind speeds show coherent variations with NSWS, indicating a strong dynamic connection between the lower troposphere and surface. These findings deepen our understanding of ENSO's influence in driving seasonal wind resources, providing actionable insights for regional wind energy management and strategic resource planning.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 9","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GL115537","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143919337","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":"Linking European Temperature Variations to Atmospheric Circulation With a Neural Network: A Pilot Study in a Climate Model","authors":"Enora Cariou,&nbsp;Julien Cattiaux,&nbsp;Saïd Qasmi,&nbsp;Aurélien Ribes,&nbsp;Christophe Cassou,&nbsp;Antoine Doury","doi":"10.1029/2024GL113540","DOIUrl":"https://doi.org/10.1029/2024GL113540","url":null,"abstract":"<p>In Europe, temperature variations are mainly driven by the North Atlantic atmospheric circulation. Here, with data from the MIROC6 large ensemble, we investigate a convolutional neural network (a UNET) for reconstructing daily temperature anomalies in Europe from Sea Level Pressure (SLP) as a proxy of the atmospheric circulation, and we compare the results with a traditional analogs approach. We show an excellent ability of the UNET to estimate temperature variations given information from SLP only. This novel method outperforms the analogs method, at both daily and inter-annual time scales. Our study also shows that during the training, the UNET learns information such as the seasonal cycle of the relationship between sea-level pressure and temperature anomalies, which could explain part of its excellent scores. This exploratory work opens up promising prospects for estimating the contribution of atmospheric variability to observed temperature variations.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 9","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL113540","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143919336","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":"Analyzing Compound Flooding Drivers Across the US Gulf Coast States","authors":"Meraj Sohrabi,&nbsp;Hamed Moftakhari,&nbsp;Hamid Moradkhani","doi":"10.1029/2025GL114769","DOIUrl":"https://doi.org/10.1029/2025GL114769","url":null,"abstract":"<p>Analyzing flood events has been the focus of numerous studies across local, regional, and global scales, aiming to understand their magnitude, drivers, and spatiotemporal distributions. Traditionally, flood hazards are defined by analyzing the likelihood of flood drivers exceeding their respective thresholds. This approach relies on events around gauge locations with accessible records. The availability of reanalysis and satellite data sets now allows us to leverage data from multiple flood reporting agencies to examine various flood event types, including compound and non-compound events, and their drivers. We analyzed three decades of flood events in the US Gulf Coast states, where compound flood events are common. We found that rainfall is the predominant driver, contributing to over 45% of reported floods classified as compound events. Fluvial and pluvial floods are more frequent and severe during tropical seasons, and especially during the Fall compared with other calendar seasons.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 9","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GL114769","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143919521","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}