Geophysical Research Letters最新文献

{"title":"Scaling High-Resolution Soil Organic Matter Composition to Improve Predictions of Potential Soil Respiration Across the Continental United States","authors":"Cheng Shi,&nbsp;Maruti Mudunuru,&nbsp;Maggie Bowman,&nbsp;Qian Zhao,&nbsp;Jason Toyoda,&nbsp;Will Kew,&nbsp;Yuri Corilo,&nbsp;Odeta Qafoku,&nbsp;John R. Bargar,&nbsp;Satish Karra,&nbsp;Emily B. Graham","doi":"10.1029/2024GL113091","DOIUrl":"https://doi.org/10.1029/2024GL113091","url":null,"abstract":"<p>Despite the importance of microbial soil organic matter (SOM) respiration in regulating the flux of carbon between soils and the atmosphere, soil carbon cycling models remain primarily based on climate and soil properties, leading to large uncertainty in predictions. To address this knowledge gap, we analyzed high-resolution water-extractable SOM profiles from soil cores collected across the United States by the 1,000 Soils Pilot of the Molecular Observation Network. Our innovation lies in using machine learning to distill thousands of SOM formula into tractable units; and it enables integrating data from molecular measurements into soil respiration models. In surface soils, SOM chemistry provided better estimates of potential soil respiration than soil physicochemistry, and using them combined yielded the best prediction. Overall, we identify specific subsets of organic molecules that may improve predictions of global soil respiration and create a strong basis for developing new representations in process-based models.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 4","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL113091","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143396951","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":"Complementing Dynamical Downscaling With Super-Resolution Convolutional Neural Networks","authors":"Deeksha Rastogi,&nbsp;Haoran Niu,&nbsp;Linsey Passarella,&nbsp;Salil Mahajan,&nbsp;Shih-Chieh Kao,&nbsp;Pouya Vahmani,&nbsp;Andrew D. Jones","doi":"10.1029/2024GL111828","DOIUrl":"https://doi.org/10.1029/2024GL111828","url":null,"abstract":"<p>Despite advancements in Artificial Intelligence (AI) methods for climate downscaling, significant challenges remain for their practicality in climate research. Current AI-methods exhibit notable limitations, such as limited application in downscaling Global Climate Models (GCMs), and accurately representing extremes. To address these challenges, we implement an AI-based methodology using super-resolution convolutional neural networks (SRCNN), trained and evaluated on 40 years of daily precipitation data from a reanalysis and a high-resolution dynamically downscaled counterpart. The dynamical downscaled simulations, constrained using spectral nudging, enable the replication of historical events at a higher resolution. This allows the SRCNN to emulate dynamical downscaling effectively. Modifications, such as incorporating elevation data and data pre-processing enhances overall model performance, while using exponential and quantile loss functions improve the simulation of extremes. Our findings show SRCNN models efficiently and skillfully downscale precipitation from GCMs. Future work will expand this methodology to downscale additional variables for future climate projections.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 4","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL111828","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143389397","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":"Intrinsic Spatial Scales of River Stores and Fluxes and Their Relative Contributions to the Global Water Cycle","authors":"Jeffrey Wade,&nbsp;Cédric H. David,&nbsp;Elyssa L. Collins,&nbsp;Michael Denbina,&nbsp;Arnaud Cerbelaud,&nbsp;Manu Tom,&nbsp;John T. Reager,&nbsp;Renato P. M. Frasson,&nbsp;James S. Famiglietti,&nbsp;Tong Lee,&nbsp;Michelle M. Gierach","doi":"10.1029/2024GL113052","DOIUrl":"https://doi.org/10.1029/2024GL113052","url":null,"abstract":"<p>The Earth's rivers vary in size across several orders of magnitude. Yet, the relative significance of small upstream reaches compared to large downstream rivers in the global water cycle remains unclear, challenging the determination of adequate spatial resolution for observations. Here, we use monthly simulations of river stores and fluxes to investigate the intrinsic spatial scales of the global river water cycle. We frame these scale-dependent river dynamics in terms of observational capabilities, assessing how the size of rivers that can be resolved influences our ability to capture key global hydrologic stores and fluxes. By filtering reaches by estimated river widths, we quantify the relative contribution of global river reaches by size and estimate that over 17% of global discharge to ocean and nearly 9% of the world's river storage lies within rivers smaller than 100 m—hence revealing both strengths and limitations of current observational capabilities.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 4","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL113052","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143397146","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":"Simultaneous Two-Point Study of the Martian Bow Shock Affected by an Interplanetary Coronal Mass Ejection: Tianwen-1 and MAVEN Observations","authors":"Ming Wang,&nbsp;Jiaqi Zhang,&nbsp;Jianyong Lu,&nbsp;Lianghai Xie,&nbsp;Fuhao Qiao,&nbsp;Qi Xu,&nbsp;Jinyu Li,&nbsp;Guanchun Wei,&nbsp;Baohang Qu,&nbsp;Lei Li","doi":"10.1029/2024GL112219","DOIUrl":"https://doi.org/10.1029/2024GL112219","url":null,"abstract":"<p>The Martian bow shock (BS) plays a significant role in the Martian plasma environment. Based on observations from Tianwen-1 and MAVEN, we first report two cases of simultaneous two-point crossings of the Martian BS affected by an interplanetary coronal mass ejection (ICME) event. The findings suggest that high solar wind dynamic pressure, <i>P</i>_<i>d</i>, and interplanetary magnetic field intensity, <i>B</i>_<i>t</i>, within an ICME event have opposite effects on the Martian BS. A high <i>P</i>_<i>d</i> causes the BS to move closer to the planet, while a strong <i>B</i>_<i>t</i> makes it move outward. The precise location of the BS depends on which factor dominates each time under specific ICME conditions. The two examined cases indicate that the Martian BS tends to move outward under an ICME event with a generally large IMF magnitude. The Wang, Xie, et al. (2020, https://doi.org/10.3847/1538-4357/abbc04) model can accurately predict the location of the Martian BS under the examined ICME event.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 4","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL112219","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143389400","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":"Ice Thickness-Induced Variations in Effective Pressure and Basal Conditions Influence Seasonal and Multi-Annual Ice Velocity at Sermeq Kujalleq (Jakobshavn Isbræ)","authors":"Xi Lu,&nbsp;Andrew Sole,&nbsp;Stephen J. Livingstone,&nbsp;Gong Cheng,&nbsp;Liming Jiang,&nbsp;Tom Chudley,&nbsp;Brice Noël,&nbsp;Daan Li","doi":"10.1029/2024GL111092","DOIUrl":"https://doi.org/10.1029/2024GL111092","url":null,"abstract":"<p>Acceleration of Sermeq Kujalleq has been linked to the retreat of its calving front. However, models consistently underestimate its ice-flow variability, indicating that important physical processes might be ignored, which introduces uncertainties in projecting its future mass loss and sea-level rise contribution. Using the Ice-sheet and Sea-level System Model, we simulate Sermeq Kujalleq from 2016 to 2022 constrained by sub-monthly ice front positions. Changes in front position explain &gt;76% of the velocity variations but with a spatially and seasonally varying misfit between modeled and observed velocities up to 30 km upstream. This misfit significantly correlates with variations in height above flotation within 10 km of the terminus. Incorporating these variations into the model by scaling the basal shear stress reduces the average misfit by over 90%. This indicates that seasonal variations in ice thickness-induced effective pressure and basal conditions play a crucial role in controlling intra-annual and longer-term ice-flow variations.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 4","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL111092","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143397070","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":"Enhancing Nowcasting With Multi-Resolution Inputs Using Deep Learning: Exploring Model Decision Mechanisms","authors":"Yuan Cao,&nbsp;Lei Chen,&nbsp;Junjing Wu,&nbsp;Jie Feng","doi":"10.1029/2024GL113699","DOIUrl":"https://doi.org/10.1029/2024GL113699","url":null,"abstract":"<p>Nowcasting methods based on deep learning typically rely solely on radar data. However, effectively leveraging multi-source data with diverse spatio-temporal resolutions remains a significant challenge in the field. To address this challenge, we propose and validate a novel deep learning model for nowcasting, termed Nowcastformer. This model utilizes radar data and upper-air atmospheric variables, and has been pretrained on satellite data from non-target regions. Quantitative statistical assessments demonstrate that both the integration of multi-source data and the implementation of pre-training strategies enhance the model's performance. Additionally, we conduct a comprehensive analysis of predictor importance, revealing a trend where atmospheric variables become increasingly important as the forecast horizon increases. To illustrate the model's interpretability, we employ the integrated gradients method, which highlights critical areas in representative cases and provides insights into the model's decision-making process.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 4","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL113699","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143397071","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":"Observation of Electric Field Enhancement at Ion Composition Boundary at Mars and Its Relation to Oxygen Acceleration","authors":"Sergey D. Shuvalov,&nbsp;Laila Andersson,&nbsp;Kathleen Gwen Hanley,&nbsp;Jasper S. Halekas,&nbsp;David L. Mitchell,&nbsp;Jared R. Espley","doi":"10.1029/2024GL113584","DOIUrl":"https://doi.org/10.1029/2024GL113584","url":null,"abstract":"<p>Direct electric field measurements during certain ionosphere-magnetosheath transitions on the dayside of Mars reveal a presence of localized (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>&lt;</mo>\u0000 </mrow>\u0000 <annotation> ${&lt; } $</annotation>\u0000 </semantics></math>20 km thickness along vertical direction) strong (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>&gt;</mo>\u0000 </mrow>\u0000 <annotation> ${ &gt;} $</annotation>\u0000 </semantics></math>40 mV/m) electric field located at the solar wind stagnation point. This electric field is nearly collocated with the ion composition boundary where ionospheric oxygen ions are observed to be accelerated up to <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 </mrow>\u0000 <annotation> ${sim} $</annotation>\u0000 </semantics></math>1 keV, forming a layer of higher temperature plasma around the stagnation point. Simulations demonstrate that the observed localized electric field enhancement can create this hotter plasma layer population on either side of the boundary. This plasma layer can have an impact on the solar wind coupling with the planet and forms a reservoir for heavy ion escape.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 4","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL113584","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143397147","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":"Poloidal Field Line Resonances Driven by a Fast Wave","authors":"Andrew Wright,&nbsp;Thomas Elsden,&nbsp;Alexander Degeling,&nbsp;Ian R. Mann,&nbsp;Louis Ozeke,&nbsp;Timothy Yeoman,&nbsp;Jasmine Sandhu,&nbsp;Kazue Takahashi","doi":"10.1029/2024GL111670","DOIUrl":"10.1029/2024GL111670","url":null,"abstract":"<p>We present numerical simulations of the excitation of resonant poloidal Alfvén waves. The resulting Alfvén waves could be loosely described as “high-<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>m</mi>\u0000 </mrow>\u0000 <annotation> $m$</annotation>\u0000 </semantics></math>” (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>m</mi>\u0000 </mrow>\u0000 <annotation> $m$</annotation>\u0000 </semantics></math> is the azimuthal wave number) in as much as the azimuthal scale of the wave is much less than the scale in the direction normal to <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>L</mi>\u0000 </mrow>\u0000 <annotation> $L$</annotation>\u0000 </semantics></math>-shells. Such waves are generally excited by wave-particle interactions. In this article we show how resonant poloidal Alfvén waves can be excited by a fast mode (of large azimuthal scale) in a cold plasma. The key property that enables this is a three-dimensional equilibrium, which facilitates the process of phasemixing in the azimuthal direction. We show that the classification of resonant Alfvén waves as high-<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>m</mi>\u0000 </mrow>\u0000 <annotation> $m$</annotation>\u0000 </semantics></math> and low-<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>m</mi>\u0000 </mrow>\u0000 <annotation> $m$</annotation>\u0000 </semantics></math> has limited applicability in 3D inhomogeneous media and suggest an alternative classification be based on the excitation mechanism.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 3","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL111670","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143375267","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":"Statistical Survey of Loss Cone Electrons Observed In Situ in the Inner Magnetosphere","authors":"R. Takahara,&nbsp;I. Shinohara,&nbsp;S. Kasahara,&nbsp;K. Asamura,&nbsp;S. Yokota,&nbsp;K. Keika,&nbsp;Y. Kazama,&nbsp;S.-Y. Wang,&nbsp;S. W. Y. Tam,&nbsp;T.-F. Chang,&nbsp;B.-J. Wang,&nbsp;C.-W. Jun,&nbsp;T. Hori,&nbsp;A. Matsuoka,&nbsp;M. Teramoto,&nbsp;K. Yamamoto,&nbsp;Y. Kasahara,&nbsp;S. Matsuda,&nbsp;A. Kumamoto,&nbsp;A. Shinbori,&nbsp;F. Tsuchiya,&nbsp;Y. Miyoshi","doi":"10.1029/2024GL112948","DOIUrl":"10.1029/2024GL112948","url":null,"abstract":"<p>We report a statistical result of electrons inside the loss cone with energies of 67 eV–88 keV using electron measurements obtained in situ by the Arase satellite in the inner magnetosphere around the magnetic equator for 60 months. Loss cone electrons are found with a high occurrence probability from the nightside to the dawnside at approximately <i>L</i> = 6. For 641 eV–88 keV electrons, the high-occurrence region shifts toward later magnetic local times (MLTs) with increasing loss cone electron energy. The spatial distribution of the occurrence probability around MLT = 22–3 at <i>L</i> = 5–6 is consistent with the calculated average resonance energy distribution of whistler mode chorus waves near the magnetic equator. These results suggest that pitch angle scattering driven by chorus waves plays the main role in electron precipitation in this region.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 3","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL112948","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143375268","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":"Revealing the Circulation Patterns Most Conducive to Regional Heatwave in Southeast Asia and the Mechanisms Behind","authors":"Yang Lyu,&nbsp;Jingyu Wang,&nbsp;Xiefei Zhi,&nbsp;Shoupeng Zhu,&nbsp;Hugh Zhang,&nbsp;Joshua Lee,&nbsp;Yi Fan,&nbsp;Yan Ji,&nbsp;Edward Park,&nbsp;Xianfeng Wang","doi":"10.1029/2024GL112190","DOIUrl":"10.1029/2024GL112190","url":null,"abstract":"<p>The increasing frequency of heatwaves over Southeast Asia (SEA) is impacting human health, infrastructure and economies. Understanding the relationship between large-scale circulation patterns and heatwaves is crucial for improving predictions and reducing damages. In this study, four distinct circulation patterns conducive to SEA heatwaves are identified by the self-organizing map. Three circulation patterns are associated with high-pressure systems over the mid-latitude Western Pacific and SEA, significantly influenced by El Niño–Southern Oscillation (ENSO). In addition to these common high-pressure patterns, a low-pressure dominant pattern is identified, characterized by two enhanced low-pressure systems over the Tibetan Plateau and mid-latitude Western Pacific, which deplete a considerable amount of moisture, resulting in diminished cloud cover and rapid warming across continental SEA. Further analysis reveals that all patterns are significantly modulated by Madden Jullian Oscillation (MJO) activities, each showing distinct peak occurrences in different MJO phases, with further links to ENSO and the Indian Ocean Dipole.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 3","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL112190","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143375269","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}