Journal of Geophysical Research: Earth Surface最新文献

{"title":"Spatial Variability and Drivers of Salt Marsh Cliff Erosion in the Dutch Wadden Sea: From Observation to Simulation","authors":"S. Dzimballa,&nbsp;V. Kitsikoudis,&nbsp;P. W. J. M. Willemsen,&nbsp;E. O. Folmer,&nbsp;B. W. Borsje,&nbsp;I. Y. Georgiou,&nbsp;M. C. Bregman,&nbsp;D. C. M. Augustijn","doi":"10.1029/2025JF008855","DOIUrl":"https://doi.org/10.1029/2025JF008855","url":null,"abstract":"<p>Lateral erosion of salt marshes via cliff retreat is a primary cause of global marsh loss, driven by interactions between hydrodynamics, sediment, and vegetation. While previous studies show a linear relationship between wave power and cliff retreat, models based on this relationship are largely unvalidated for short-term (sub-yearly) and spatially variable predictions, limiting their practical application. This study addresses this gap by integrating a process-based subgrid cliff erosion model into a 2DH hydrodynamic model, validated using high-resolution UAV-derived DEMs over 9 months in a Dutch Wadden Sea marsh. The site featured 20–60 cm high cliffs retreating at ∼0.9 m/yr. Once calibrated, the model captured overall erosion trends and volumes, confirming the linear wave power-retreat relationship when averaged across the marsh. However, it did not account for local effects, like artificial structures, cliff undercutting, or mass failure, highlighting the need for site-specific calibration and better understanding of underlying processes. Simulations under varying hydrodynamic conditions assessed marsh cliff vulnerability. Water levels determine the location and timing of cliff exposure, while wave energy dictates retreat magnitude. Yearly storm surges caused the most significant erosion, whereas more extreme surges (5–10 years return-period) submerged the marsh edge, limiting further erosion. This research shows that the linear wave-power relationship is scale-dependent: it can be calibrated for longer-term, marsh-averaged erosion volumes when sufficient local data support a linear relationship, but its applicability is limited for within-marsh, shorter-term forecasting. Accurate simulation and effective coastal management require further understanding of the processes and implementation of non-linear erosion mechanisms.</p>","PeriodicalId":15887,"journal":{"name":"Journal of Geophysical Research: Earth Surface","volume":"131 8","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JF008855","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148753196","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":"Surface Mineralogy and Hydrological Controls on “Hotspots” of Dust Emission at Etosha Pan, Namibia","authors":"N. S. Wallum,&nbsp;R. G. Bryant,&nbsp;G. F. S. Wiggs,&nbsp;R. L. Reynolds,&nbsp;H. L. Goldstein,&nbsp;J. A. Leidelmeijer,&nbsp;J. M. Nield,&nbsp;M. C. Baddock","doi":"10.1029/2026JF009216","DOIUrl":"https://doi.org/10.1029/2026JF009216","url":null,"abstract":"<p>Ephemeral lake beds are globally significant sources of atmospheric mineral dust aerosols, yet emissions from these landforms exhibit considerable spatial and temporal variability. The complex interactions between climatic drivers and surface properties that govern dust emissions remain poorly understood, contributing to uncertainties in model predictions of atmospheric dust concentrations and their global effects. In this study, we used multitemporal satellite remote sensing combined with model reanalysis data from 2018 to 2022 to investigate the mineralogical, hydrological, and climatic controls on dust emission “hotspots” at Etosha Pan, Namibia. A record of dust source locations derived from MODIS and MSG-SEVIRI observations was used to identify spatially discrete clusters (hotspots) of recurrent dust emission. Surface mineral composition at these sites was analyzed through linear spectral unmixing of Landsat 8–9 Operational Land Imager data to estimate the relative abundance of evaporite and clay mineral endmembers, with results validated against X-ray diffraction analyses of field-collected sediment samples. Our findings indicate that dust emission hotspots are associated with the formation of evaporite crusts, produced by salt efflorescence following wet-season precipitation and ephemeral flooding. Strong winds during the dry season can disrupt these crusts, exposing large quantities of fine sediments that are extremely susceptible to aeolian entrainment. These results highlight the critical role of surface crust mineralogy, influenced by hydrological history, in controlling dust emission dynamics. This approach provides a transferable framework for identifying and characterizing hydrological and mineralogical controls on dust source regions in other dryland playa environments, with potential applications for improving regional and global dust emission modeling.</p>","PeriodicalId":15887,"journal":{"name":"Journal of Geophysical Research: Earth Surface","volume":"131 8","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JF009216","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148752726","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":"Basal Force Probability Distributions in Thin-Layer Granular Flows","authors":"Jun Fang,&nbsp;Hui Tang,&nbsp;Yifei Cui,&nbsp;Jens M. Turowski,&nbsp;Lu Jing,&nbsp;Clarence Edward Choi","doi":"10.1029/2025JF008892","DOIUrl":"https://doi.org/10.1029/2025JF008892","url":null,"abstract":"<p>Extreme geophysical flows, such as granular and debris flows, can significantly shape the landscape in steep lands and generate seismic signals that can be recorded over long distances. However, direct field measurements needed to constrain the granular physics remain difficult due to the damage potential of those flows. Here, we investigate how the granular flows impact the bedrock channel using a computational fluid dynamics model coupled with the discrete-element method, systematically varying the grain size, discharge, and water content for two flow regimes: unsteady and steady flows. These numerical experiments allow us to quantify the basal forces as probability density functions (PDFs). We test those PDFs based on several evaluation metrics, such as determination coefficient, residual sum of squares, Wasserstein distance, and information entropy for 12 selected probability distributions. We find that the <i>t</i> Location-Scale and lognormal distributions are best-performing among the tested distributions for unsteady and steady flows, respectively, rather than the exponential and generalized Pareto distributions in previous studies. Our results demonstrate that grain size, discharge, and water content strongly influence the basal-force distribution. Furthermore, we established the relationships between flow kinematics and basal force statistics. Results indicate that compared to effective friction coefficient and volume fraction, the fitted parameters of the probability distributions exhibit monotonic relationships with Froude number, granular temperature, and dimensionless velocity. These results provide empirical constraints for modeling extreme geophysical flow incision and inversion of seismic signals generated by such flows.</p>","PeriodicalId":15887,"journal":{"name":"Journal of Geophysical Research: Earth Surface","volume":"131 8","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JF008892","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148752987","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":"Long-Distance Aeolian Dust Deposited on the Island of Crete (Greece): Detection, Characterization, and Provenance","authors":"S. Bitzan,&nbsp;C. L. Blanchet,&nbsp;S. Pichat,&nbsp;G. E. Christidis,&nbsp;K. Schepanski,&nbsp;F. Kirsten","doi":"10.1029/2025JF008992","DOIUrl":"https://doi.org/10.1029/2025JF008992","url":null,"abstract":"<p>Long-distance aeolian dust transport represents one of the largest sediment fluxes on Earth, with North Africa being a dominant source. The island of Crete in the Eastern Mediterranean lies within major transport pathways but remains underexplored regarding multi-proxy fingerprinting of deposited dust. Here, we evaluate the contribution of long-range dust, sorting effects caused by the regional topography, and the contributions of different source areas on dust deposited in Crete over 15 months (03–2023 to 06–2024). We analyzed the bulk mineral, grain-size, and radiogenic (Nd, Pb, and Sr) isotope composition of monthly deposition samples at seven sites across western Crete as well as local surface material and reference aerosols from Libya. The deposited material is dominated by long-range transported dust originating from northern Africa, as indicated by the presence of palygorskite and distinct mineral and isotopic signatures from local surface sediments. Grain-size distributions are largely uniform across measurement sites and dominated by silts, with temporal rather than spatial variability controlling compositional changes. Isotopic data suggest major contributions from source areas in northeastern Algeria and north Libya to northwestern Egypt. The absence of gypsum and the variability of clay mineral proportions suggest transport related fractionation and mixing of multiple source regions. Shifts in mineral assemblages suggest changes in provenance from northeastern Algeria in winter to northeastern Libya and northwestern Egypt in summer. These results highlight the dynamic and seasonally variable nature of dust provenance in the Eastern Mediterranean and emphasize the value of integrating mineralogical and isotope approaches for robust source attribution.</p>","PeriodicalId":15887,"journal":{"name":"Journal of Geophysical Research: Earth Surface","volume":"131 8","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JF008992","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148647786","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":"Seismic Imaging of the Remnant Southern Crater Wall of the Yilan Crater via Integrated Analysis of Seismic Surface Waves and First Arrivals","authors":"Lei Zhu,&nbsp;Yudi Pan,&nbsp;Tan Qin,&nbsp;Xu Sun,&nbsp;Haoyan Chen,&nbsp;Jiaqi Li","doi":"10.1029/2026JF009346","DOIUrl":"https://doi.org/10.1029/2026JF009346","url":null,"abstract":"<p>The Yilan impact crater in northeastern China is generally well preserved, except for a ∼2 km gap along its southern rim. To investigate the structural disturbances recorded beneath the remnant southern crater wall, we conducted a shallow-seismic survey in the southern part of the Yilan crater. We constructed the S-wave and P-wave velocity models by inverting the surface-wave dispersion curves and first-arrival travel times individually. K-means clustering was applied to the multi-parameter velocity models to transform the geophysical attributes into a zonation of the shallow subsurface that shows lithological variations. By comparing the clustered model with the extrapolated rim topography estimated by its preserved part on the Earth's surface, we found that the fractured bedrock of the remnant southern crater wall lies buried beneath more than 10 m of loose sediments. This indicates that the southern part of the crater wall has been significantly eroded and covered by sediments but still exists. It also shows that the farther away the rim is from its surface pinching point, the stronger the erosion and sedimentation have been. Overall, this study demonstrates the effectiveness of combining multiple seismic approaches with statistical clustering for structural delineation of the remnant southern crater wall buried below the Earth's surface and provides new geophysical evidence on the deformation of the Yilan crater.</p>","PeriodicalId":15887,"journal":{"name":"Journal of Geophysical Research: Earth Surface","volume":"131 8","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148647639","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":"Linking Fluvial Incision and Landslide Activity in a Tectonically Active Landscape","authors":"Wenlong Yu,&nbsp;Weiwei Zhan,&nbsp;Weile Li,&nbsp;Arvind Singh,&nbsp;Jia-Jyun Dong","doi":"10.1029/2025JF008905","DOIUrl":"https://doi.org/10.1029/2025JF008905","url":null,"abstract":"<p>Tectonic uplift drives fluvial incision and hillslope adjustment in mountains, and landslides are a major mode of hillslope response that contributes to landscape evolution. However, quantitative constraints on the coupling between fluvial incision and landslide activity remain limited, largely due to difficulties in quantifying incision and isolating the fluvial incision effect from other landslide-controlling factors. We addressed this problem in the Xiaojin Basin on the eastern Tibetan Plateau, where the main rivers evolved within a Triassic folded belt that allowed structural controls to be evaluated while minimizing lithologic, topographic, and meteorologic variability along the channels. We used normalized channel steepness index (<i>k</i>_sn) as a morphometric proxy for relative fluvial incision, and combined river profile analysis with a new landslide inventory, slope unit mapping, and InSAR deformation data. Paired comparisons showed that mean <i>k</i>_sn was higher along landslide reaches than adjacent non-landslide reaches. To reduce the influence of local landslide perturbations, we further evaluated slope unit-averaged <i>k</i>_sn, which better represented the longer-wavelength incisional background. At this scale, the landslide occurrence probability increased with <i>k</i>_sn. This relationship was further modulated by the slope structure, with the strongest dependence observed on anti-dip slopes and transverse slopes. In contrast, InSAR-derived landslide deformation rates showed weak correlation with <i>k</i>_sn. These results indicate that fluvial incision primarily controls the location of landslides, rather than their current deformation rates. Overall, these findings indicate that k_sn captures the long-term incisional boundary conditions that govern landslide occurrence, implying its value for landslide susceptibility assessment in transient mountain landscapes.</p>","PeriodicalId":15887,"journal":{"name":"Journal of Geophysical Research: Earth Surface","volume":"131 8","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148617293","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":"Fluvial-Aeolian Interactions and Landscape Recovery After Extreme Events: A Death Valley Dune Field After Hurricane Hilary","authors":"Mackenzie Day,&nbsp;Alana Archbold,&nbsp;Jordan Bretzfelder,&nbsp;Michael Zanetti","doi":"10.1029/2025JF008995","DOIUrl":"https://doi.org/10.1029/2025JF008995","url":null,"abstract":"<p>In arid landscapes, wind drives slow, persistent sediment transport year after year, while rare floods can reshape the landscape in a matter of hours. Recent record-breaking rainfall, following Hurricane Hilary in August 2023, caused widespread flooding, erosion, and deposition in the Mesquite Flat Dune Field, extending across Death Valley, California. In this work, we study the interaction between fluvial and aeolian sediment transport associated with this extreme event, specifically focusing on landscape recovery. Using repeat satellite images, field observations, and terrestrial LiDAR, we quantify flood depths, sediment volumes, and the pace of landscape recovery. Floodwaters penetrated more than one km into the dune-field interior, resulting in interdune ponds of standing water up to 3.9 m in depth. As the water receded, deposition of fine sediment from the turbid waters left millimeter-to-centimeter thick mud drapes on the dunes and interdunes, armoring the surface from aeolian erosion. Where fluvial erosion removed entire dunes, nascent dunes re-formed in less than 2 years. Repeat field observations show that fluvial mud deposits were rapidly eroded by aeolian abrasion and unlikely to contribute to the rock record except where they were rapidly buried by dune migration.</p>","PeriodicalId":15887,"journal":{"name":"Journal of Geophysical Research: Earth Surface","volume":"131 8","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148617291","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":"Predicting Riparian Seedling Removal: A Mechanistic Scour Model Supported by Lab and Field Evidence","authors":"Elowyn M. Yager,&nbsp;Walter Bertoldi,&nbsp;Annunziato Siviglia,&nbsp;Elena Chenet,&nbsp;Andrew W. Tranmer","doi":"10.1029/2026JF009129","DOIUrl":"https://doi.org/10.1029/2026JF009129","url":null,"abstract":"<p>Riparian seedlings growing on river bars, islands, and floodplains create feedback processes with hydraulics, sediment transport, and channel morphodynamics. For example, intact seedling uprooting by the flow typically requires some degree of sediment scour before seedling removal. Estimates of the critical scour depth (<i>L</i>_<i>c</i>) that allows for individual seedling uprooting are often based on the resisting root force (<i>F</i>_<i>P</i>). We develop a new mechanistic <i>F</i>_<i>P</i> equation that includes root-sediment friction from different grain size distributions, root irregularities, and lateral root areas. Simple laboratory experiments demonstrate that root-sediment friction coefficients from previous studies may be orders of magnitude lower than those that occur in riparian areas with coarse grain size distributions. We test different forms of our equation using field measured <i>F</i>_<i>P</i> to find that accurate <i>F</i>_<i>P</i> predictions require: (a) a range of root-sediment frictional effects, (b) declining taproot diameter with below ground distance, and (c) root hair effects. Combining our <i>F</i>_<i>P</i> equation with simple flow calculations, we calculate that <i>L</i>_<i>c</i> for an individual seedling is not constant as often assumed but depends on the bed grain size distribution, flow conditions, aboveground seedling patch density, and belowground and aboveground individual seedling biomass properties. We calculate similar <i>L</i>_<i>c</i> for invasive and native seedling species, suggesting that invasive seedling removal through targeted high-flow dam releases requires careful consideration of potential effects on native seedlings.</p>","PeriodicalId":15887,"journal":{"name":"Journal of Geophysical Research: Earth Surface","volume":"131 7","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JF009129","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148615972","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":"Retrogressive Thaw Slump Morphology and Dynamics in Saline Permafrost in Northeast Greenland","authors":"S. Eppinger,&nbsp;T. H. Lorentzen,&nbsp;M. Angelopoulos,&nbsp;T. Ingeman-Nielsen,&nbsp;D. A. Rudd,&nbsp;M. Marcer,&nbsp;M. Krautblatter","doi":"10.1029/2025JF008848","DOIUrl":"https://doi.org/10.1029/2025JF008848","url":null,"abstract":"<p>Saline permafrost occupies a significant portion of permafrost in the Northern Hemisphere and extends several kilometers inland from the present Arctic coastline. However, its thermal conditions, mechanical degradation and geomorphological impacts are poorly understood. We aim to understand the impacts of saline permafrost on retrogressive thaw slump (RTS) evolution, especially when unfrozen highly saline pockets that persist at subzero temperatures, known as cryopegs, are present. In August 2022, we investigated two RTSs near the Zackenberg Research Station in Northeast Greenland. We combined electrical resistivity tomography, laboratory temperature-resistivity calibrations, stratigraphic records of exposures and cores, in situ temperature measurements and laboratory analysis of soil properties such as salt content. Our results indicate that the main trigger of RTS development is the exposure of massive ground ice exposed by riverbank erosion during a flood event in 2016. The two RTSs remained highly active between 2016 and 2020, with an overall maximum extent of almost 2,000 m² total in 2022. Through geophysical and laboratory data, we prove the existence of cryopegs within marine sediments and hypothesize that they slow down RTS retreat when they become dry. Our results suggest that the evolution of RTSs in saline permafrost is influenced by cryopegs and sensitive fine-grained sediments. We hypothesize that the cryopegs and the massive ice exposed before RTS initiation and within the headwall extend further beneath the station, making it prone to subsidence and further thaw-related hazards.</p>","PeriodicalId":15887,"journal":{"name":"Journal of Geophysical Research: Earth Surface","volume":"131 7","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JF008848","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148615973","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":"Constraining the Distribution of 3D Fractal Structures in Mud Flocs","authors":"Brayden Noh,&nbsp;Justin A. Nghiem,&nbsp;Kimberly Litwin Miller,&nbsp;Dongchen Wang,&nbsp;Michael P. Lamb","doi":"10.1029/2025JF008830","DOIUrl":"https://doi.org/10.1029/2025JF008830","url":null,"abstract":"&lt;p&gt;Mud builds coastal landscapes and carries pollutants and carbon, yet predicting its transport is difficult because mud aggregates into flocs that control settling rates. Flocs are typically characterized using fractal theory with a constant fractal dimension &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mfenced&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;n&lt;/mi&gt;\u0000 &lt;mi&gt;f&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mo&gt;=&lt;/mo&gt;\u0000 &lt;mn&gt;2.0&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/mfenced&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $left({n}_{f}=2.0right)$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, inferred from aggregated size–settling velocity data, despite diverse fractal structures. We conducted experiments on freshwater flocs under varied shear stress and organic concentration to characterize this diversity. Rather than the conventional approach of aggregating settling data to infer &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;n&lt;/mi&gt;\u0000 &lt;mi&gt;f&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${n}_{f}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, we grouped measurements by the two-dimensional (2D) box-counting dimension from particle tracking, partially resolving structural variability. This stratified method reveals that &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;n&lt;/mi&gt;\u0000 &lt;mi&gt;f&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${n}_{f}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; increases with shear velocity and decreases with organic matter (OM) content, trends obscured by aggregation. The stratified analysis resolves &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;n&lt;/mi&gt;\u0000 &lt;mi&gt;f&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${n}_{f}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; variations of 0.2–0.35 units across experimental conditions, whereas conventional aggregation reduces this range roughly fivefold. The inferred primary particle diameter &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;d&lt;/mi&gt;\u0000 &lt;mi&gt;p&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${d}_{p}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; co-varies with these conditions, and the concurrent variation of &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;n&lt;/mi&gt;\u0000 &lt;mi&gt;f&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;anno","PeriodicalId":15887,"journal":{"name":"Journal of Geophysical Research: Earth Surface","volume":"131 7","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148616085","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}