Journal of Geophysical Research: Earth Surface最新文献

{"title":"Dynamic Thermomechanical Modeling of Rock-Ice Avalanches: Understanding Flow Transitions, Water Dynamics, and Uncertainties","authors":"Jessica Munch,&nbsp;Yu Zhuang,&nbsp;Rajesh Kumar Dash,&nbsp;Perry Bartelt","doi":"10.1029/2024JF007805","DOIUrl":"https://doi.org/10.1029/2024JF007805","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <p>The rapid melting of glaciers and thawing of permafrost in mountainous regions have heightened the danger of rock-ice avalanches. These avalanches pose a severe threat due to their potential to transform into water-saturated debris flows. The catastrophic event in Chamoli, India, on 7 February 2021, illustrates the devastating consequences of such processes. Developing a model capable of predicting the dynamics and extent of these events is imperative for natural hazard science and disaster mitigation. In response, we propose a depth-averaged rock-ice avalanche model encompassing four distinct materials: rock, ice, snow, and water. The model integrates crucial physical processes, including frictional heating, phase changes, ground material entrainment, and air-blast hazards. Through a system of mass and momentum balance equations extended with grain flow and internal energy equations, the model captures heat exchanges and resulting phase changes as the fragmented material flows. Focusing on identifying the primary water source in the flow and testing the model on the 2021 Chamoli event, we quantify water's influence on flow dynamics and regime transitions. However, uncertainties persist in heat transfer physics and quantifying the hydro-meteorological state of the flow path. Our thermo-mechanical model enables the simulation of complex avalanches and identifies key flow transitions: powder cloud formation and potential debris flow transformation. The study underscores the pivotal role of water in avalanche dynamics and the challenge of accurately quantifying water content within the flow, necessitating comprehensive ground assessments for effective disaster management.</p>\u0000 </section>\u0000 </div>","PeriodicalId":15887,"journal":{"name":"Journal of Geophysical Research: Earth Surface","volume":"129 10","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JF007805","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142525074","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":"Calving Dynamics and the Potential Impact of Mélange Buttressing at the Western Calving Front of Thwaites Glacier, West Antarctica","authors":"Anna Crawford,&nbsp;Jan Åström,&nbsp;Douglas I. Benn,&nbsp;Adrian Luckman,&nbsp;Rupert Gladstone,&nbsp;Thomas Zwinger,&nbsp;Fredrik Robertsén,&nbsp;Suzanne Bevan","doi":"10.1029/2024JF007737","DOIUrl":"https://doi.org/10.1029/2024JF007737","url":null,"abstract":"<p>The western region of the wide Thwaites Glacier terminus is characterized by a near-vertical calving front. The grounding line at this western calving front (WCF) rests on a relatively high ridge, behind which exists a reverse-sloping bed; retreat of the grounding line into this over-deepening basin could therefore expose deep calving faces that may be subject to ice-cliff failure. Here, we use the 3D Helsinki Discrete Element Model to identify the factors that control the calving dynamics in this location. We then focus on the ability of mélange to influence these dynamics given the wide embayment in which Thwaites Glacier terminates. We find that calving along the WCF is currently influenced by ice flow across the grounding line and consequent longitudinal tensile stress and rift formation. Calving is slowed in simulations that are initiated with a highly constricted mélange, with a thicker mélange suppressing calving entirely. We liken the constrained simulations to a scenario in which mélange piles behind a large grounded iceberg. In a future which may see calving become a more dominant control on the retreat of Thwaites Glacier, this type of blockage will be necessary for robust force chains to develop and transmit resistive forces to the terminus. The ability of the mélange to hinder calving at this location will be determined by the presence and rigidity of binding land-fast sea ice and iceberg keel depths. Therefore, it is necessary to represent calving, mélange and sea ice in a single framework to predict the fate of Thwaites Glacier.</p>","PeriodicalId":15887,"journal":{"name":"Journal of Geophysical Research: Earth Surface","volume":"129 10","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JF007737","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142525170","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":"Sediment Source Partitioning and Budgeting Over Historical Timescales in a Glacierized, Mountain Catchment","authors":"Mike Turley,&nbsp;Marwan A. Hassan,&nbsp;Andre Zimmermann,&nbsp;Olav Lian","doi":"10.1029/2024JF007819","DOIUrl":"https://doi.org/10.1029/2024JF007819","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <p>Managing and living with geohazards is especially challenging in mountain landscapes and requires an understanding of catchment-scale sediment dynamics and internal system functioning. While sediment budgeting is a valuable framework, challenges remain including partitioning sediment yield by source and grain size and addressing scale issues. This study advances our understanding of bed material dynamics in glacierized mountain catchments by applying a range of complementary techniques to measure sediment transfers in the Fitzsimmons Creek watershed. First, we measured the historical bed material yield using field surveys and historical air photo analysis, revealing an average specific sediment yield of 210 Mg km⁻² yr⁻¹, that varied by a factor of 17 over the 76-year record. Hydro-meteorological and historical analyses suggest that gravel extraction had the largest impact over the past three decades, while an extreme landslide and flood event produced the highest recorded sediment yield. Second, we constructed a detailed sediment budget along the river system using high-resolution, multi-temporal lidar and geomorphic mapping data. Sediment source partitioning indicates that landslide, active channel, and floodplain sources each contributed about one-third of the total sediment supply. Net degradation occurred along the valley bottom upstream of the fan-delta, resulting in steadily increasing downstream sediment yield. This trend is punctuated by chronic landsliding near the outlet, driven by postglacial incision through glaciogenic sediments at a hanging valley step. Contemporary glacial and proglacial sources were not measured directly but surprisingly contributed minimally. These findings provide insight into the sediment dynamics of glacierized mountain catchments and their potential controls.</p>\u0000 </section>\u0000 </div>","PeriodicalId":15887,"journal":{"name":"Journal of Geophysical Research: Earth Surface","volume":"129 10","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JF007819","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142524842","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":"Conditional Effects of Tides and Waves on Sediment Supply to Salt Marshes","authors":"Jianwei Sun,&nbsp;Bram van Prooijen,&nbsp;Xianye Wang,&nbsp;Weiming Xie,&nbsp;Fan Xu,&nbsp;Qing He,&nbsp;Zhengbing Wang","doi":"10.1029/2024JF007686","DOIUrl":"https://doi.org/10.1029/2024JF007686","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <p>The survival of salt marshes, especially facing future sea-level rise, requires sediment supply. Sediment can be supplied to salt marshes via two routes: through marsh creeks and over marsh edges. However, the conditions of tides and waves that facilitate sediment import through these two routes remain unclear. To understand when and how sediment is imported into salt marshes, 2-month measurements were conducted to monitor tides, waves, and suspended sediment concentration (SSC) in Paulina Saltmarsh, a meso-macrotidal system. The results show that the marsh creek tends to import sediment during neap tides with waves. A tidal cycle with a small tidal range result in weaker flow in the marsh creek during ebb tides, reducing the export of sediment. Waves enhance sediment supply to the marsh creek by eroding mudflats. However, strong waves can directly resuspend sediment in marsh creeks during spring tides when the water level is above the marsh canopy, enhancing sediment export through creeks. Net sediment import over marsh edges requires the opposite tidal and wave conditions: spring tides with weak waves. Spring tides provide stronger hydrodynamics, facilitating sediment import over the marsh edge. Increased SSC during the ebb phase can occur with strong waves over the marsh edge, resulting in net sediment export. Therefore, the net import or export of sediment, through the creek and over the marsh edge, depends on the combination of tidal and wave conditions. These conditions can vary between estuaries and even individual marshes. Understanding these conditions is crucial for better management of salt marshes.</p>\u0000 </section>\u0000 </div>","PeriodicalId":15887,"journal":{"name":"Journal of Geophysical Research: Earth Surface","volume":"129 10","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142447624","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":"Subaerial Profiles at Two Beaches: Equilibrium and Machine Learning","authors":"M. N. Siegelman,&nbsp;R. A. McCarthy,&nbsp;A. P. Young,&nbsp;W. O’Reilly,&nbsp;H. Matsumoto,&nbsp;M. Johnson,&nbsp;C. Mack,&nbsp;R. T. Guza","doi":"10.1029/2023JF007524","DOIUrl":"https://doi.org/10.1029/2023JF007524","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <p>Shoreline position (e.g., beach width) is a critical component of flooding and overtopping forecasts but difficult to predict accurately. We model beach width changes with a supervised machine learning (ML) approach informed by equilibrium principles. The time history of wave energy anomalies that force equilibrium models is used as an ML input feature. The sweeping simplifying equilibrium model assumptions relating beach width change to anomalies are replaced with data-based ML results. Supervised learning regression methods including linear, support vector, decision trees, and ensemble regressors are tested. Observations for model training and testing includes weekly to quarterly beach elevation surveys spanning approximately 500 m alongshore and 8 years at two beaches, each supplemented with several months of ∼100 sub-weekly surveys. These beaches, with different sediment types (sand vs. sand-cobble mix), both widen in summer in response to the seasonal wave climate, in agreement with a generic equilibrium model. Differences in backshore erodability contribute to differing beach responses in the stormiest (El Niño) year that are reproduced by a simple extra trees regression model but not by the equilibrium model. With sufficiently extensive training data, the ML model outperforms equilibrium by providing flexibility and complexity in the response to wave forcing. The present ML and equilibrium models both fail to simulate a uniquely stunted beach recovery unlike other recoveries in the training data.</p>\u0000 </section>\u0000 </div>","PeriodicalId":15887,"journal":{"name":"Journal of Geophysical Research: Earth Surface","volume":"129 10","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JF007524","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142449156","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":"Scenario-Based Volcano Slope Stability Hazard Analysis: Case Study of Augustine Volcano, Alaska","authors":"Shreya Kanakiya","doi":"10.1029/2024JF007862","DOIUrl":"https://doi.org/10.1029/2024JF007862","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <p>Volcanoes worldwide have undergone cyclic destruction of their edifices, generating catastrophic volcanic debris avalanches. Augustine Volcano in Alaska, USA, has a history of debris avalanches, causing cyclic destruction of the edifice and cascading hazards. These collapses, together with eruption-related changes in the edifice structure, change the slope stability hazard of the volcano over time. This study aims to develop a current view of the slope stability hazard at Augustine Volcano by (a) characterizing collapse-prone source areas on the edifice under various scenarios typical of dynamic volcanic environments and (b) identifying the controlling factors that underlie the slope stability hazard. Scenario-based slope stability assessment was conducted using a quasi-3D limit equilibrium method to test for the effect of various factors that drive or resist failure, including topography, shallow edifice structure, strength of edifice-forming materials, pore fluid pressure distribution, and local and regional seismicity. Results show that in all scenarios assessed, the slopes of Augustine Volcano are stable with a factor of safety (FOS) greater than 1. The FOS, however, decreases with decreasing strength of edifice-forming materials, pore fluid pressurization, and earthquake loading. The location of the relatively less stable slope, changes to the southwestern flank when accounting for subsurface heterogeneities derived from geophysical observations. Subsurface heterogeneity is thus a key underlying factor, along with steep topography, in controlling where collapse-prone source areas occur, and it should be accounted for in volcanic slope stability hazard assessments.</p>\u0000 </section>\u0000 </div>","PeriodicalId":15887,"journal":{"name":"Journal of Geophysical Research: Earth Surface","volume":"129 10","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142447623","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":"Vortex Trapping of Suspended Sand Grains Over Ripples","authors":"Donya P. Frank-Gilchrist,&nbsp;Allison M. Penko,&nbsp;Margaret L. Palmsten,&nbsp;Joseph Calantoni","doi":"10.1029/2023JF007620","DOIUrl":"https://doi.org/10.1029/2023JF007620","url":null,"abstract":"<p>Coastal hydrodynamics and morphodynamics integrate the effects of small-scale fluid-sediment interactions; yet, these small-scale processes are not well understood. To investigate sediment trapping by turbulent coherent structures or vortices, the transport of coarse sand over ripples was analyzed in a small-oscillatory flow tunnel with phase-separated Particle Image and Tracking Velocimetry. Results from one of the first direct measurements of vortex-trapped sand grains under oscillatory flows are presented. The vortices mobilized sand grains along the ripple slopes just prior to flow reversal and transported the suspended sediment grains. During several flow cycles, some sand grains were temporarily trapped in the vortex, prescribing semi-circular trajectories off-center from the vortex core in quadrants of the vortex that were closest to the ripple slope, as illustrated by Nielsen (1992, https://doi.org/10.1142/1269). Comparisons of the horizontal sediment grain velocity with the horizontal fluid velocity yielded a linear relationship with a slope of 0.87. The vertical grain velocities also varied linearly with the vertical fluid velocity with a slope of approximately 1 and an offset of −0.08 m <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>s</mi>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>1</mn>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${mathrm{s}}^{-1}$</annotation>\u0000 </semantics></math>. The offset is close to the still water settling velocity for coarse sand grains, as hypothesized during vortex trapping. Additionally, estimates of the off-center distance, between the centers of the semi-circular sediment paths and vortex cores, compared well with the ratio of the settling velocity to the radian frequency of the vortex yielding a linear regression slope of 0.99. Improved understanding of vortex trapping effects on sediment dynamics may decrease uncertainty in model predictions of large-scale coastal hydrodynamics and sediment transport.</p>","PeriodicalId":15887,"journal":{"name":"Journal of Geophysical Research: Earth Surface","volume":"129 10","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JF007620","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142447625","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":"Modeling Sediment Fluxes From Debris-Rich Basal Ice Layers","authors":"Ethan Pierce,&nbsp;Irina Overeem,&nbsp;Guillaume Jouvet","doi":"10.1029/2024JF007665","DOIUrl":"https://doi.org/10.1029/2024JF007665","url":null,"abstract":"<p>Sediment erosion, transport, and deposition by glaciers and ice sheets play crucial roles in shaping landscapes, provide important nutrients to downstream ecosystems, and preserve key indicators of past climate conditions in the geologic record. While previous work has quantified sediment fluxes from subglacial meltwater, we also observe sediment entrained within basal ice, transported by the flow of the glacier itself. However, the formation and evolution of these debris-rich ice layers remains poorly understood and rarely represented in landscape evolution models. Here, we identify a characteristic sequence of basal ice layers at Mendenhall Glacier, Alaska. We develop a numerical model of frozen fringe and regelation processes that describes the co-evolution of this sequence and explore the sensitivity of the model to key properties of the subglacial sedimentary system, using the Instructed Glacier Model to parameterize ice dynamics. Then, we run numerical simulations over the spatial extent of Mendenhall Glacier, showing that the sediment transport model can predict the observed basal ice stratigraphy at the glacier's terminus. From the model results, we estimate basal ice layers transport between 23,300 <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>m</mi>\u0000 <mn>3</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${mathrm{m}}^{3}$</annotation>\u0000 </semantics></math> <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>a</mi>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>1</mn>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${mathrm{a}}^{-1}$</annotation>\u0000 </semantics></math> and 39,800 <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>m</mi>\u0000 <mn>3</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${mathrm{m}}^{3}$</annotation>\u0000 </semantics></math> <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>a</mi>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>1</mn>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${mathrm{a}}^{-1}$</annotation>\u0000 </semantics></math> of sediment, mostly entrained in the lowermost ice layers nearest to the bed, maximized by high effective pressures and slow, convergent flow fields. Overall, our results highlight the role of basal sediment entrainment in delivering eroded material to the glacier terminus and indicate that this process should not be ignored in broader models of landscape evolution.</p>","PeriodicalId":15887,"journal":{"name":"Journal of Geophysical Research: Earth Surface","volume":"129 10","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142443561","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":"Experiments on Constriction-Pool-Widening Morphology in Bedrock Canyons","authors":"Kyle M. Kusack,&nbsp;Tingan Li,&nbsp;Jeremy G. Venditti","doi":"10.1029/2024JF007808","DOIUrl":"https://doi.org/10.1029/2024JF007808","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <p>Bedrock rivers often alternate between relatively wide unconstrained reaches and conspicuously narrow deep incised bedrock reaches (canyons). These bedrock canyons exhibit a constriction-pool-widening (CPW) morphology that consists of a lateral constriction, a deeply scoured pool formed downstream of the constriction, and a channel widening at or near the pool exit. To explore how CPWs are formed in bedrock canyons, we hypothesize that the lateral constriction at the canyon entrance forces a CPW to form allogenically with subsequent CPWs propagating further downstream. Our hypothesis was tested experimentally in a flume channel with a forced lateral constriction at the canyon entrance. Our experiment shows that the forced constriction can cause a primary CPW to form allogenically because the backwater upstream of the forced constriction causes sediment deposition that creates an elevation drop, promoting flow and sediment to plunge toward the bed and carve a primary pool. Channel widening occurs at the primary pool exit because sediment deposit forms that deflects sediment into the banks, causing lateral erosion. Downstream of the primary widening, channel width declines and a new lateral constriction forms, which causes the formation of pools and widening downstream, resulting in downstream CPW propagation. In our experiment, the bedrock channel evolved until a persistent alluvial cover formed, reaching a steady state morphology without further vertical erosion until perturbed by higher discharge. Our experiment shows that discharge variation is necessary for a channel to evolve in the absence of uplift.</p>\u0000 </section>\u0000 </div>","PeriodicalId":15887,"journal":{"name":"Journal of Geophysical Research: Earth Surface","volume":"129 10","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JF007808","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142443560","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":"A Wind Tunnel Experiment Study on Splash Functions During Sand Saltation","authors":"C. W. Jiang,&nbsp;Z. C. Zhang,&nbsp;X. Y. Wang,&nbsp;Z. B. Dong,&nbsp;F. Jun Xiao","doi":"10.1029/2024JF007863","DOIUrl":"https://doi.org/10.1029/2024JF007863","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <p>Splash functions delineate the intricate interaction between wind-driven particles and the bed. However, due to limitations in measurement methods, achieving a comprehensive understanding of splash functions remains challenging. In this study, we utilized a high-speed system and particle trajectory tracking algorithm to reconstruct 857 collision events involving natural sand particles obtained from field samples and artificial glass microspheres interacting with a bed composed of analogous particles in a wind tunnel. During the experiments, the ratio of the wind shear velocity (<i>u</i>_*) to the impact threshold (<i>u</i>_*ti) consistently ranged between approximately 1.22 and 1.79. Our findings indicate that the impact angle remains independent of both impact velocity and particle size, maintaining an approximate value of 10.5 ± 6.5°. The evaluation of splash functions depends on the criterion used to define ejection, that is, the ratio of the centroid's height of the liftoff particles to their particle size (<i>H</i>/<i>d</i>). Additionally, at the same critical height (<i>H</i>/<i>d</i> = 1.5), our splash functions show differences of varying degrees from previous experiments and theoretical studies performed under no wind conditions. We believe that the main reason for these differences may be that the energy exchange between the bed surface and the airflow increases the looseness of the large-particle (&gt;0.1 mm) bed surface. These findings hold significant implications for accurately modeling sand-bed collisions in natural environments.</p>\u0000 </section>\u0000 </div>","PeriodicalId":15887,"journal":{"name":"Journal of Geophysical Research: Earth Surface","volume":"129 10","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142429840","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}