Journal of Geophysical Research: Earth Surface最新文献

{"title":"Constructed Dunes and Roads Reduce Decadal Washover Flux on Transgressing Barrier Islands","authors":"E. R. Eisemann,&nbsp;A. B. Rodriguez,&nbsp;D. J. Wallace,&nbsp;S. L. Gremillion","doi":"10.1029/2024JF008089","DOIUrl":"https://doi.org/10.1029/2024JF008089","url":null,"abstract":"<p>On developed barrier islands, washover deposition is regarded as a hazard, despite its essential role in natural island transgression. Measures taken to prevent erosion and halt overwash such as dune stabilization can exacerbate disequilibrium and accelerate island drowning. Although such management practices have been implemented on some U.S. barrier islands for over a century, decadal-scale remote sensing data have only recently become available to evaluate their long-term impacts on island morphology. We analyzed a 30-km stretch of northern Hatteras Island, North Carolina, divided into seven zones with similar geomorphology and management history. This region includes the Pea Island National Wildlife Refuge, with minimal development beyond a shore-parallel road (NC 12), and three towns. Using 11 lidar data sets (2005–2019) and 2013 satellite imagery, we quantified washover flux, geomorphology, and human development metrics along 20 m spaced transects. Zone-averaged washover flux ranged from 0.99 to 5.19 m³/m/yr, aligning with sediment core-based metrics but lower than values reported in single-storm studies and the equilibrium flux (6.48 m³/m/yr) required for mass conservation during island retreat. Decadal washover flux was not significantly correlated with dune heights, shoreline change, or development density but was linked to development setback, dune height change, and barrier island volume deficit. Flux variability was high even within similarly developed zones, with dune and road maintenance alone reducing washover flux and extent by ∼50%. This suggests that management practices, rather than development density or traditional predictors like dune height, play a dominant role in controlling washover susceptibility, significantly restricting natural barrier island rollover processes.</p>","PeriodicalId":15887,"journal":{"name":"Journal of Geophysical Research: Earth Surface","volume":"130 6","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144148394","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":"So Long, and Thanks for All the Flysch","authors":"Amy E. East","doi":"10.1029/2025JF008522","DOIUrl":"https://doi.org/10.1029/2025JF008522","url":null,"abstract":"&lt;p&gt;AGU Editors-in-Chief traditionally write a farewell editorial upon completing their service to the journal, and I have put off writing mine for three months, the longest I've ever procrastinated anything. It's been difficult to sit down and write a reflection on the last several years because, just as the &lt;i&gt;JGR: Earth Surface&lt;/i&gt; editorial team was changing over, the outlook of the scientific community was shifting into a time of upheaval, fear, and loss.&lt;/p&gt;&lt;p&gt;I am, of course, writing in my personal capacity, not that of a federal government employee, and I am expressing only my own views here. But like so many others, I have been deeply affected by the fiscal and organizational cuts to science in recent months. Although I am fortunate to remain employed for now, I have lost many colleagues recently to early retirement and removal. Long-planned work is being curtailed or canceled. Many of us are working with a sort of grim determination to continue doing the best job possible, under new and sometimes mystifying restrictions, knowing our remaining time in this career path could be short.&lt;/p&gt;&lt;p&gt;Our field of Earth-surface processes encompasses some of the science most at risk of de-funding and de-prioritization in the current political shift—climate change, weather- and climate-driven hazards and their effects on human communities and ecosystems—and the impacts are already affecting our authors and publications. Authors whose &lt;i&gt;JGR&lt;/i&gt; manuscripts I am still handling have told me they were required to remove the phrase “climate change” from their work during revision. Some authors are removing their names from submitted manuscripts in order not to endanger their careers by association with “controversial” topics. The loss of government funding is having profound effects across academia. As of this writing, U.S. scientists wait in some confusion to learn whether the Sixth National Climate Assessment will move forward given recent changes at the U.S. Global Change Research Program, and some authors' permitted participation in the next Intergovernmental Panel on Climate Change (IPCC) Assessment Report is also in flux. Having been in the middle of these situations directly in the last several months, some days I have difficulty recognizing our professional environment as the place I've served and thrived in for many years.&lt;/p&gt;&lt;p&gt;None of this detracts from the immense gratitude I have for our editorial team and what we accomplished over the past six years at &lt;i&gt;JGR: Earth Surface&lt;/i&gt;. It has been an absolute privilege—the highlight of my career—to share the responsibility of running this journal with such excellent colleagues: Editors Olga Sergienko, Ton Hoitink, Mikael Attal, and Noah Finnegan, more than 50 Associate Editors (AEs), and the AGU Publications staff, with special thanks to Matt Giampoala, Mia Ricci, Erin Syring, and Paige Wooden. AGU Publications comprise an incredibly dedicated, skilled, and good-humored team who manage all sorts of ","PeriodicalId":15887,"journal":{"name":"Journal of Geophysical Research: Earth Surface","volume":"130 5","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JF008522","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144140372","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":"Recent Variability in Fracture Characteristics and Ice Flow of Thwaites Ice Shelf, West Antarctica","authors":"Shujie Wang,&nbsp;Patrick M. Alexander,&nbsp;Richard B. Alley,&nbsp;Zhengrui Huang,&nbsp;Byron R. Parizek,&nbsp;Amanda G. Willet,&nbsp;Sridhar Anandakrishnan","doi":"10.1029/2024JF008118","DOIUrl":"https://doi.org/10.1029/2024JF008118","url":null,"abstract":"<p>The rapidly changing Thwaites Ice Shelf is crucial for understanding ice-shelf dynamical processes and their implications for sea-level rise from Antarctica. Fractures, particularly their vertical structure, are key to ice-shelf structural integrity but remain poorly measured. To address this, we developed a fracture-characterization workflow using ICESat-2 ATL03 geolocated photon heights, producing the first time-series vertical measurements of fractures across Thwaites from 2018 to 2024. We introduced the fracture depth/freeboard ratio as a normalized metric to quantify vertical fracture extent, serving as an indicator of structural damage. This metric enabled us to track fracture evolution in both the eastern ice shelf and western glacier tongue. In the eastern section, fracturing intensified along the northwestern shear zone and near the grounding line, in a positive feedback loop between enhanced fracturing and accelerated flow. The western section maintained an active rift formation zone about 15 km downstream of the historical grounding line. Flow velocity changes in this section were primarily confined to the unconstrained downstream portion, exhibiting an overall deceleration trend, while the upstream area remained stable. This contrast highlights the role of lateral margin conditions in governing ice-shelf fracture and flow behavior. Changes in the eastern section showed some correspondence with warm winter air temperatures, reduced sea ice, and persistent warm ocean anomalies at shallower depths, suggesting that atmosphere-sea ice-ocean interactions influence ice-shelf structural integrity through basal processes. Future research should integrate satellite-derived fracture observations with numerical models of ice fracture and flow to better capture the dynamics of ice-shelf weakening and retreat.</p>","PeriodicalId":15887,"journal":{"name":"Journal of Geophysical Research: Earth Surface","volume":"130 5","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JF008118","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144131602","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":"Process and Mechanism of Soil Desiccation Cracking Triggered by Surface Defects Based on DEM Modeling","authors":"Tao Wang,&nbsp;Chao-Sheng Tang,&nbsp;Wei-Jie Liu,&nbsp;Qing Cheng,&nbsp;Zhi-Xiong Zeng","doi":"10.1029/2024JF008121","DOIUrl":"https://doi.org/10.1029/2024JF008121","url":null,"abstract":"<p>Soil desiccation cracking is a ubiquitous natural phenomenon that intensifies under drought conditions. Experimental tests and field observations have shown that desiccation cracks often initiate at defects such as foreign inclusions, tiny pits, and uneven soil surfaces. However, the underlying mechanisms by which defects affect soil desiccation cracking remain poorly understood due to the lack of stress field information from laboratory tests. This study utilizes the three-dimensional Discrete Element Method to examine the micromechanics of how defects impact soil desiccation cracking. In this research, sand inclusions were used to model defects, and the effects of defect size, quantity, and distribution were carefully analyzed. The findings reveal that defects cause significant local stress concentration, triggering arc-shaped micro-cracks that eventually develop into Y-shaped cracking patterns. Defects influence the surrounding maximum principal tensile stress field within a range of 2–2.5 times the defect diameter. When a crack enters this influence zone, it is drawn toward the defect. The presence of defects increases soil heterogeneity, disrupting the sequential and hierarchical pattern of desiccation cracks observed in homogeneous soil specimens. Consequently, the crack network in soils containing defects consists of both orthogonal and non-orthogonal cracks.</p>","PeriodicalId":15887,"journal":{"name":"Journal of Geophysical Research: Earth Surface","volume":"130 5","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144100535","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":"Quantifying Bed Surface Roughness in Bedrock and Boulder-Bed Rivers","authors":"R. C. Houseago,&nbsp;R. A. Hodge,&nbsp;B. Asher,&nbsp;R. I. Ferguson,&nbsp;C. R. Hackney,&nbsp;R. J. Hardy,&nbsp;T. B. Hoey,&nbsp;J. P. L. Johnson,&nbsp;S. P. Rice,&nbsp;E. M. Yager,&nbsp;T. Yamasaki","doi":"10.1029/2024JF007996","DOIUrl":"https://doi.org/10.1029/2024JF007996","url":null,"abstract":"<p>The surface roughness of river beds affects flow resistance and sediment transport. In rough-bed rivers (RBRs), where flow is shallow relative to roughness height, the surface roughness is difficult to define due to complex multi-scale roughness elements (bedrock, boulders, and sediment patches). Here, neither the sediment grain size distribution percentiles (e.g., <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>D</mi>\u0000 <mn>84</mn>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${D}_{84}$</annotation>\u0000 </semantics></math>) nor the bed elevation standard deviation <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mfenced>\u0000 <msub>\u0000 <mi>Z</mi>\u0000 <mi>σ</mi>\u0000 </msub>\u0000 </mfenced>\u0000 </mrow>\u0000 <annotation> $left({Z}_{sigma }right)$</annotation>\u0000 </semantics></math> fully captures the surface roughness. This paper uses high-resolution digital elevation models of 20 RBR reaches to evaluate their channel morphology and surface roughness. A set of 29 different multi-scale elevation, gradient-based, and area-based, roughness metrics are assessed. Correlation analysis and robust feature selection identified interchangeable metrics, revealing which roughness metrics provided independent information on channel characteristics. Principal component analysis and hierarchical clustering analysis showed that a comprehensive description of RBR topography requires the concurrent use of multiple metrics encompassing (a) a vertical or horizontal scale-based roughness metric, (b) a slope- or area-based metric, and (c) surface elevation skewness or kurtosis. Slope- and area-based metrics can include roughness directionality relative to the bulk flow. We demonstrate how surface roughness metrics, specifically the use of multiple metrics in unison, are suitably capable of representing and distinguishing between RBRs with differing characteristics. In some cases, rivers with different morphology types (e.g., boulder bed or bedrock) are found to have greater similarity in their surface roughness metrics than rivers classified as morphologically similar. We then discuss RBR morphological and roughness characteristics in the context of flow resistance and sediment transport processes.</p>","PeriodicalId":15887,"journal":{"name":"Journal of Geophysical Research: Earth Surface","volume":"130 5","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JF007996","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144074569","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":"Continuous Solid-Fluidization Transition Mechanism of Loess Mudflow: Insights From Laboratory Experiments and Implications for Geophysical Processes","authors":"Daozheng Wang,&nbsp;Xingang Wang,&nbsp;Xiaoqing Chen,&nbsp;Qiangbing Huang,&nbsp;Jiading Wang,&nbsp;Baoqin Lian,&nbsp;Fei Wang","doi":"10.1029/2024JF008123","DOIUrl":"https://doi.org/10.1029/2024JF008123","url":null,"abstract":"<p>Solid-fluidization transition-induced flow-like events pose significant threats to both ecological systems and human society. This geophysical phenomenon undergoes a continuous and catastrophic solid-fluidization-solid retransition, which often leads to severe disasters. A series of flume and rheological tests were conducted to explore the continuous solid-fluidization-solid retransition mechanism of sedimentary loess. The results showed that the flow distance after phase retransition increased by 39.5% compared with the first flowslip distance. With increasing rainfall intensity, the moisture content during phase transition tended to decrease while the time required for reactivation lengthened. Rheological analyses revealed that the reduction and recovery of storage modulus exhibited by thixotropy is a crucial mechanism in the phase retransition of soil, and they have significant time-concentration dependence. A higher soil water content leads to a longer structural recovery time and stronger thixotropy, which agrees well with the results of flume tests. Our experimental data <i>N</i>_Sav and <i>N</i>_Bag showed a positive power-law relationship and had similar fitting coefficients to the field case data, indicating that our experimental results have successfully captured the kinematic and rheological characteristics of real mudflow events. This study suggests that thixotropy can be used to interpret complex phase retransition processes in mudflow and can also help to explain the hypermobility and reactivation of many large geophysical processes, such as pyroclastic flows.</p>","PeriodicalId":15887,"journal":{"name":"Journal of Geophysical Research: Earth Surface","volume":"130 5","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143950059","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":"Discharge Promotes Melt and Formation of Submarine Ice-Shelf Channels at the Beardmore Glacier Grounding Zone","authors":"Andrew O. Hoffman,&nbsp;Howard Conway,&nbsp;Joséphine Anselin,&nbsp;Keith W. Nicholls,&nbsp;Jonathan Kingslake,&nbsp;Paul Winberry,&nbsp;Michelle Koutnik,&nbsp;Knut Christianson,&nbsp;Pierre Dutrieux","doi":"10.1029/2024JF007921","DOIUrl":"https://doi.org/10.1029/2024JF007921","url":null,"abstract":"<p>Using radar data from the Beardmore Glacier grounding zone, we image a narrow subglacial channel (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>300</mn>\u0000 <mo>−</mo>\u0000 <mn>500</mn>\u0000 </mrow>\u0000 <annotation> $300-500$</annotation>\u0000 </semantics></math> m wide) that reaches a height of 200 m above the ambient ice-shelf draft. Using repeat ICESat-2 observations and Worldview digital elevation models, we show that this channel we observe with radar is part of a system of channels. These channels form near the grounding zone where the axis of the channels runs up-gradient in smoothed ice base elevation (perpendicular to smoothed ice base elevation contours). Downstream, these features are advected with the flow and expressed as Eulerian surface elevation change in differenced co-registered digital elevation models. Continuity calculations indicate that melt rates within the channel are at least 20 m <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mtext>yr</mtext>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>1</mn>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${text{yr}}^{-1}$</annotation>\u0000 </semantics></math>. Idealized one-dimensional plume modeling indicates these melt rates require substantial meltwater discharge and are geographically continuous extensions of subglacial conduits we image upstream of the grounding zone. These basal-melt rates are <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>27</mn>\u0000 <mo>×</mo>\u0000 </mrow>\u0000 <annotation> $27times $</annotation>\u0000 </semantics></math> higher than the ambient basal-melt rates in the Ross. Asymmetric melt across the width of the channel suggests there is cross-channel ocean boundary current that may affect the efficiency of energy exchange across the ice-shelf ocean boundary layer within the channel. This is consistent with recent model experiments that suggest ice shelf basal channel shape determines channelized ice-ocean interactions.</p>","PeriodicalId":15887,"journal":{"name":"Journal of Geophysical Research: Earth Surface","volume":"130 5","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JF007921","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143932367","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":"The Influence of Gravel-Bed Structure on Grain Mobility Thresholds: Comparison of Force-Balance Approaches","authors":"D. Whitfield,&nbsp;E. R. C. Baynes,&nbsp;R. A. Hodge,&nbsp;S. P. Rice,&nbsp;E. M. Yager","doi":"10.1029/2025JF008333","DOIUrl":"https://doi.org/10.1029/2025JF008333","url":null,"abstract":"<p>Grain force-balance models utilize grain protrusion and in-situ resistance force data to evaluate the likely distributions of gravel-bed sediment entrainment thresholds, specifically dimensionless critical shear stress (<i>τ</i>*_<i>c</i>). These methods can give insight into the spatial variability of particle mobilities both within a channel, and between different gravel-beds, but are yet to be evaluated across multiple sites with varying texture and fabric. We evaluate two published force-balance approaches: (a) a Monte Carlo style sampling approach using grain size and topography distributions from field measurements; and (b) an automated point cloud segmentation and analysis approach with an updated set of force-balance equations, Pro+. We compare the workflows, assumptions and inputs for each approach, apply them to an extensive UK-wide data set comprising 45 upland riverbeds, and evaluate the estimated <i>τ</i>*_<i>c</i> distributions. We find that mobility thresholds estimated from both methods are variable, with median <i>τ</i>*_<i>c</i> ranging from 0.05 to 0.15, and are consistent with published values of approximately 0.02–0.1. Uncertainties in grain sampling strategy or point cloud segmentation quality lead to markedly different grain size distributions between approaches, but their resulting influences on <i>τ</i>*_<i>c</i> distributions are small relative to the range of estimated <i>τ</i>*_<i>c</i>. Sensitivity analyses on <i>τ</i>*_<i>c</i> distributions for grain-size fractions also show that bed mobilities are sensitive to the roughness height of the velocity profile. We highlight uncertainties associated with these approaches, suggest areas for further targeted comparisons between methods, and provide guidance for the application of grain force-balance models for estimating entrainment thresholds and bed stability in gravel-bed rivers.</p>","PeriodicalId":15887,"journal":{"name":"Journal of Geophysical Research: Earth Surface","volume":"130 5","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JF008333","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143908958","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":"Discrete Simulations of Fluid-Driven Transport of Naturally Shaped Sediment Particles","authors":"Qiong Zhang,&nbsp;Eric Deal,&nbsp;J. Taylor Perron,&nbsp;Jeremy G. Venditti,&nbsp;Santiago J. Benavides,&nbsp;Matthew Rushlow,&nbsp;Ken Kamrin","doi":"10.1029/2024JF007937","DOIUrl":"https://doi.org/10.1029/2024JF007937","url":null,"abstract":"<p>The particles in natural bedload transport processes are usually aspherical and span a range of shapes and sizes, which is challenging to be represented in numerical simulations. We assemble existing numerical methods to simulate the transport of natural gravel (NG). Starting with computerized tomographic scans of natural grains, our method approximates the shapes of these grains by “gluing” spheres (SP) of different sizes together with overlaps. The conglomerated SP move using a Discrete Element Method which is coupled with a Lattice Boltzmann Method fluid solver, forming the first complete workflow from particle shape measurement to high-resolution simulations with hundreds of distinct shapes. The simulations are quantitatively benchmarked by flume experiments. Beyond the flume, in a more generalized wide wall-free geometry, the numerical tool is used to further test a recently proposed modified sediment transport relation, which takes particle shape effects into account, including the competition between hydrodynamic drag and material friction. Unlike a physical experiment, our simulations allow us to vary the hydrodynamic drag coefficient of the NG independently of the material friction. The results support the modified sediment transport relation. The simulations also provide insights into particle-level kinematics, such as particle orientations. Though particles below the bed surface prefer to orient with their shortest axes perpendicular to the bed surface, with a decaying tendency with an increasing height above the bed surface, the orientational preferences in transport processes are much weaker than those in settling processes. NG rotates relatively freely during bedload transport.</p>","PeriodicalId":15887,"journal":{"name":"Journal of Geophysical Research: Earth Surface","volume":"130 5","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JF007937","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143889138","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":"Details and Mechanisms of Permafrost Ground Deformation on the Tibetan Plateau Revealed by GNSS-IR and In Situ Hydrothermal Monitoring","authors":"Wei Chen,&nbsp;Lingxiao Wang,&nbsp;Lin Zhao,&nbsp;Wei Wan,&nbsp;Shibo Liu,&nbsp;Chong Wang,&nbsp;Lewen Zhao,&nbsp;Guangyue Liu,&nbsp;Defu Zou,&nbsp;Chengjia Liang,&nbsp;Yuanwei Wang,&nbsp;Chenqi Huang","doi":"10.1029/2024JF008012","DOIUrl":"https://doi.org/10.1029/2024JF008012","url":null,"abstract":"<p>This study employs the Global Navigation Satellite System-Interferometric Reflectometry (GNSS-IR) technique, along with in situ hydrothermal data, to explore the details and mechanisms of permafrost ground surface deformation in the hinterland Tibetan Plateau. Through analyzing GNSS data collected from November 2021 to April 2024, seasonal deformation of up to approximately 5 cm, caused by active layer freeze-thaw cycles, was identified. Additionally, more than 2 years of continuous monitoring revealed a clear ground subsidence rate of 2.7 cm per year due to permafrost thawing. We compared the GNSS-IR monitored deformation with simulated deformation using in situ soil moisture and temperature profiles at 5–220 cm depth and found that the correlation reached 0.9 during the active-layer thawing and freezing period; we also observed that following an exceptionally thawing season, the subsequent thawing season experiences notably greater thaw subsidence. Furthermore, we analyzed the differences in GNSS-IR monitoring results with and without the inclusion of Beidou Navigation Satellite System (BDS) signals, and found that the inclusion of BDS signals reduced the standard deviation of GNSS-IR results by an average of 0.24 mm on snow-free periods, but increased by an average of 0.12 mm during the snow cover periods. This may be due to the longer wavelength of the BDS signal, which exhibits greater diffraction through snow and reduces signal reflectivity compared to other satellite systems. The research results demonstrate the potential and ability of continuous GNSS-IR ground surface deformation monitoring in revealing and exploring the hydrothermal processes within permafrost under climate change.</p>","PeriodicalId":15887,"journal":{"name":"Journal of Geophysical Research: Earth Surface","volume":"130 5","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143884028","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}