Earth Surface Dynamics最新文献

{"title":"Marsh-induced backwater: the influence of non-fluvial sedimentation on a delta's channel morphology and kinematics","authors":"Kelly M. Sanks, John B. Shaw, Samuel M. Zapp, José Silvestre, Ripul Dutt, Kyle M. Straub","doi":"10.5194/esurf-11-1035-2023","DOIUrl":"https://doi.org/10.5194/esurf-11-1035-2023","url":null,"abstract":"Abstract. We investigate the interaction of fluvial and non-fluvial sedimentation on the channel morphology and kinematics of an experimental river delta. We compare two deltas: one that evolved with a proxy for non-fluvial (“marsh”) sedimentation (treatment experiment) and one that evolved without the proxy (control). We show that the addition of the non-fluvial sediment proxy alters the delta's channel morphology and kinematics. Notably, the flow outside the channels is significantly reduced in the treatment experiment, and the channels are deeper (as a function of radial distance from the source) and longer. We also find that both the control and treatment channels narrow as they approach the shoreline, though the narrowing is more pronounced in the control compared to the treatment. Interestingly, the channel beds in the treatment experiment often exist below sea level in the terrestrial portion of the delta top, creating a ∼ 0.7 m reach of steady, non-uniform backwater flow. However, in the control experiment, the channel beds generally exist at or above relative sea level, creating channel movement resembling morphodynamic backwater kinematics and topographic flow expansions. Differences between channel and far-field aggradation produce a longer channel in-filling timescale for the treatment compared to the control, suggesting that the channel avulsions triggered by a peak in channel sedimentation occur less frequently in the treatment experiment. Despite this difference, the basin-wide timescale of lateral channel mobility remains similar. Ultimately, non-fluvial sedimentation on the delta top plays a key role in the channel morphology and kinematics of an experimental river delta, producing channels which are more analogous to channels in global river deltas and which cannot be produced solely by increasing cohesion in an experimental river delta.","PeriodicalId":48749,"journal":{"name":"Earth Surface Dynamics","volume":"293 7","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135272354","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":"Automated riverbed composition analysis using deep learning on underwater images","authors":"Alexander A. Ermilov, Gergely Benkő, Sándor Baranya","doi":"10.5194/esurf-11-1061-2023","DOIUrl":"https://doi.org/10.5194/esurf-11-1061-2023","url":null,"abstract":"Abstract. The sediment of alluvial riverbeds plays a significant role in river systems both in engineering and natural processes. However, the sediment composition can show high spatial and temporal heterogeneity, even on river-reach scale, making it difficult to representatively sample and assess. Conventional sampling methods are inadequate and time-consuming for effectively capturing the variability of bed surface texture in these situations. In this study, we overcome this issue by adopting an image-based deep-learning (DL) algorithm. The algorithm was trained to recognise the main sediment classes in videos that were taken along cross sections underwater in the Danube. A total of 27 riverbed samples were collected and analysed for validation. The introduced DL-based method is fast, i.e. the videos of 300–400 m long sections can be analysed within minutes with continuous spatial sampling distribution (i.e. the whole riverbed along the path is mapped with images in ca. 0.3–1 m2 overlapping windows). The quality of the trained algorithm was evaluated (i) mathematically by dividing the annotated images into test and validation sets and also via (ii) intercomparison with other direct (sieving of physical samples) and indirect sampling methods (wavelet-based image processing of the riverbed images), focusing on the percentages of the detected sediment fractions. For the final evaluation, the sieving analysis of the collected physical samples were considered the ground truth. After correcting for samples affected by bed armouring, comparison of the DL approach with 14 physical samples yielded a mean classification error of 4.5 %. In addition, based upon the visual evaluation of the footage, the spatial trend in the fraction changes was also well captured along the cross sections. Suggestions for performing proper field measurements are also given; furthermore, possibilities for combining the algorithm with other techniques are highlighted, briefly showcasing the multi-purpose nature of underwater videos for hydromorphological assessment.","PeriodicalId":48749,"journal":{"name":"Earth Surface Dynamics","volume":"30 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135272589","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":"Spatial and temporal variations in rockwall erosion rates derived from cosmogenic ¹⁰Be in medial moraines at five valley glaciers around Pigne d'Arolla, Switzerland","authors":"Katharina Wetterauer, Dirk Scherler","doi":"10.5194/esurf-11-1013-2023","DOIUrl":"https://doi.org/10.5194/esurf-11-1013-2023","url":null,"abstract":"Abstract. Rockwall erosion in high-alpine glacial environments varies both temporally and spatially. Where rockwalls flank glaciers, changes in debris supply and supraglacial cover will modify ice ablation. Yet, quantifying spatiotemporal patterns in erosion across deglaciating rockwalls is not trivial. At five nearby valley glaciers around Pigne d'Arolla in Switzerland, we derived apparent rockwall erosion rates using 10Be cosmogenic nuclide concentrations ([10Be]) in medial moraine debris. Systematic downglacier sampling of six medial moraines that receive debris from rockwalls with differing orientation, slope, and deglaciation histories enabled us to assess rockwall erosion through time and to investigate how distinct spatial source rockwall morphology may express itself in medial moraine [10Be] records. Our dataset combines 24 new samples from medial moraines of Glacier du Brenay, Glacier de Cheilon, Glacier de Pièce, and Glacier de Tsijiore Nouve with 15 published samples from Glacier d'Otemma. For each sample, we simulated the glacial debris transport using a simple debris particle trajectory model to approximate the time of debris erosion and to correct the measured [10Be] for post-depositional 10Be accumulation. Our derived apparent rockwall erosion rates range between ∼ 0.6 and 10.0 mm yr−1. Whereas the longest downglacier [10Be] record presumably reaches back to the end of the Little Ice Age and suggests a systematic increase in rockwall erosion rates over the last ∼ 200 years, the shorter records only cover the last ∼ 100 years from the recent deglaciation period and indicate temporally more stable erosion rates. For the estimated time of debris erosion, ice cover changes across most source rockwalls were small, suggesting that our records are largely unaffected by the contribution of recently deglaciated bedrock of possibly different [10Be], but admixture of subglacially derived debris cannot be excluded at every site. Comparing our sites suggests that apparent rockwall erosion rates are higher where rockwalls are steep and north-facing, indicating a potential slope and temperature control on rockwall erosion around Pigne d'Arolla.","PeriodicalId":48749,"journal":{"name":"Earth Surface Dynamics","volume":"35 10","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136104522","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":"Building a bimodal landscape: bedrock lithology and bed thickness controls on the morphology of Last Chance Canyon, New Mexico, USA","authors":"Sam Anderson, Nicole Gasparini, Joel Johnson","doi":"10.5194/esurf-11-995-2023","DOIUrl":"https://doi.org/10.5194/esurf-11-995-2023","url":null,"abstract":"Abstract. We explore how rock properties and channel morphology vary with rock type in Last Chance Canyon, Guadalupe Mountains, New Mexico, USA. The rocks here are composed of horizontally to near-horizontally interbedded carbonate and sandstone. This study focuses on first- and second-order channel sections, where the streams have a lower channel steepness index (ksn) upstream and transition to higher ksn values downstream. We hypothesize that differences in bed thickness and rock strength influence ksn values, both locally by influencing bulk bedrock strength and also nonlocally through the production of coarse sediment. We collected discontinuity intensity data (the length of bedding planes and fractures per unit area), Schmidt hammer rebound measurements, and measured the largest boulder at every 12.2 m elevation contour to test this hypothesis. Bedrock and boulder mineralogy were determined using a lab-based carbonate dissolution method. High-resolution orthomosaics and digital surface models (DSMs) were generated from drone and ground-based photogrammetry. The orthomosaics were used to map channel sections with exposed bedrock. The United States Geological Survey (USGS) 10 m digital elevation models (DEMs) were used to measure channel slope and hillslope relief. We find that discontinuity intensity is negatively correlated with Schmidt hammer rebound values in sandstone bedrock. Channel steepness tends to be higher where reaches are primarily incising through more thickly bedded carbonate bedrock and lower where more thinly bedded sandstone is exposed. Bedrock properties also influence channel morphology indirectly, through coarse sediment input from adjacent hillslopes. Thickly bedded rock layers on hillslopes erode to contribute larger colluvial sediment to adjacent channels, and these reaches have higher ksn values. Larger and more competent carbonate sediment armors both the carbonate and the more erodible sandstone and reduces steepness contrasts across rock types. We interpret that in the relatively steep, high-level ksn downstream channel sections, the slope is primarily controlled by the coarse alluvial cover. We further posit that the upstream low-level ksn reaches have a base level that is fixed by the steep downstream reaches, resulting in a stable configuration, where channel slopes have adjusted to lithologic differences and/or sediment armor.","PeriodicalId":48749,"journal":{"name":"Earth Surface Dynamics","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135094101","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":"Geotechnical controls on erodibility in fluvial impact erosion","authors":"Jens M. Turowski, Gunnar Pruß, Anne Voigtländer, Andreas Ludwig, Angela Landgraf, Florian Kober, Audrey Bonnelye","doi":"10.5194/esurf-11-979-2023","DOIUrl":"https://doi.org/10.5194/esurf-11-979-2023","url":null,"abstract":"Abstract. Bedrock incision by rivers is commonly driven by the impacts of moving bedload particles. The speed of incision is modulated by rock properties, which is quantified within a parameter known as erodibility that scales the erosion rate to the erosive action of the flow. Although basic models for the geotechnical controls on rock erodibility have been suggested, large scatter and trends in the remaining relationships indicate that they are incompletely understood. Here, we conducted dedicated laboratory experiments measuring erodibility using erosion mills. In parallel, we measured uniaxial compressive strength, tensile strength, Young's modulus, bulk density, and the Poisson's ratio for the tested lithologies. We find that under the same flow conditions, erosion rates of samples from the same lithology can vary by a factor of up to 60. This indicates that rock properties that may vary over short distances within the same rock can exert a strong control on its erosional properties. The geotechnical properties of the tested lithologies are strongly cross-correlated, preventing a purely empirical determination of their controls on erodibility. The currently prevailing model predicts that erosion rates should scale linearly with Young's modulus and inversely with the square of the tensile strength. We extend this model using first-principle physical arguments, taking into account the geotechnical properties of the impactor. The extended model provides a better description of the data than the existing model. Yet, the fit is far from satisfactory. We suggest that the ratio of mineral grain size to the impactor diameter presents a strong control on erodibility that has not been quantified so far. We also discuss how our laboratory results upscale to real landscapes and long timescales. For both a revised stream power incision model and a sediment-flux-dependent incision model, we suggest that long-term erosion rates scale linearly with erodibility and that, within this theoretical framework, relative laboratory measurements of erodibility can be applied at the landscape scale.","PeriodicalId":48749,"journal":{"name":"Earth Surface Dynamics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135141960","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":"Linear-stability analysis of plane beds under flows with suspended loads","authors":"Koji Ohata, Hajime Naruse, Norihiro Izumi","doi":"10.5194/esurf-11-961-2023","DOIUrl":"https://doi.org/10.5194/esurf-11-961-2023","url":null,"abstract":"Abstract. Plane beds develop under flows in fluvial and marine environments; they are recorded as parallel lamination in sandstone beds, such as those found in turbidites. However, whereas turbidites typically exhibit parallel lamination, they rarely feature dune-scale cross-lamination. Although the reason for the scarcity of dune-scale cross-lamination in turbidites is still debated, the formation of dunes may be dampened by suspended loads. Here, we perform, for the first time, linear-stability analysis to show that flows with suspended loads facilitate the formation of plane beds. For a fine-grained bed, a suspended load can promote the formation of plane beds and dampen the formation of dunes. These results of theoretical analysis were verified with observational data of plane beds under open-channel flows. Our theoretical analysis found that suspended loads promote the formation of plane beds, which suggests that the development of dunes under turbidity currents is suppressed by the presence of suspended loads.","PeriodicalId":48749,"journal":{"name":"Earth Surface Dynamics","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134944030","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 and subglacial seismic characteristics of the largest measured jökulhlaup from the eastern Skaftá cauldron, Iceland","authors":"Eva P. S. Eibl, Kristin S. Vogfjörd, Benedikt G. Ófeigsson, Matthew J. Roberts, Christopher J. Bean, Morgan T. Jones, Bergur H. Bergsson, Sebastian Heimann, Thoralf Dietrich","doi":"10.5194/esurf-11-933-2023","DOIUrl":"https://doi.org/10.5194/esurf-11-933-2023","url":null,"abstract":"Abstract. Subglacial floods cause seismic tremors that can be located and tracked in space and time using a seismic array. Here, we shed light on the generating mechanisms of the seismic signals observed during the largest measured flood from the eastern Skaftá cauldron in the Vatnajökull ice cap, Iceland. We track the propagation of the flood in 2015 using two seismic arrays and a local seismic network in combination with GPS, hydrological, and geochemical data. We find that as the water drained from the subglacial lake beneath the cauldron, families of icequakes were generated in the area around the cauldron, while the glacier surface gradually subsided by more than 100 m. We detected a several-hours-long, non-harmonic tremor and high-frequency transient events migrating downglacier, following the subglacial flood front. We suggest that this tremor is composed of repeating, closely spaced icequakes that were generated as the glacier was being lifted, cracked, and deformed, thus enabling the subglacial water flow. When the lake had largely drained, the pressure within the underlying hydrothermal system dropped. At this time, we recorded minute-long tremor bursts emanating from the cauldron area, followed by an hour-long harmonic tremor each. We interpret these as being caused by hydrothermal explosions in the geothermal system within the cauldron and as being vigorous boiling in the crustal rocks, respectively, which is an interpretation corroborated by floodwater geochemical signals. Finally, the flood also led to detectable tremor due to more energetic flow in the rapids near Sveinstindur in the Skaftá river. We conclude that the flood generated five different seismic signal types that can be associated with five different geophysical processes, including the wide spectrum from brittle failure and explosions to boiling and turbulent flow.","PeriodicalId":48749,"journal":{"name":"Earth Surface Dynamics","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134976419","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":"Refining patterns of melt with forward stratigraphic models of stable Pleistocene coastlines","authors":"Patrick Boyden, Paolo Stocchi, Alessio Rovere","doi":"10.5194/esurf-11-917-2023","DOIUrl":"https://doi.org/10.5194/esurf-11-917-2023","url":null,"abstract":"Abstract. The warmest peak of the Last Interglacial (ca. 128–116 ka) is considered a process analogue and is often studied to better understand the effects of a future warmer climate on the Earth's system. In particular, significant efforts have been made to better constrain ice sheet contributions to the peak Last Interglacial sea level through field observation of paleo relative sea level indicators. Along tropical coastal margins, these observations are predominantly based on fossil shallow coral reef sequences, which also provide the possibility of gathering reliable U-series chronological constraints. However, the preservation of many Pleistocene reef sequences is often limited to a series of discrete relative sea level positions within the interglacial, where corals suitable for dating were preserved. This, in turn, limits our ability to understand the continuous evolution of paleo relative sea level through an entire interglacial, also affecting the possibility of unraveling the existence and pattern of sub-stadial sea level oscillations. While the interpretation of lithostratigraphic and geomorphologic properties is often used to overcome this hurdle, geological interpretation may present issues related to subjectivity when dealing with missing facies or incomplete sequences. In this study, we try to step back from a conventional approach, generating a spectrum of synthetic Quaternary subtropical fringing reefs for a site in southwestern Madagascar (Indian Ocean). We use the Dionisos forward stratigraphic model (from Beicip-Franlab) to build a fossil reef at this location. In each model run, we use distinct Greenland and Antarctica ice sheet melt scenarios produced by a coupled ANICE–SELEN glacial isostatic adjustment model. The resulting synthetic reef sequences are then used test these melt scenarios against the stratigraphic record. We propose that this sort of stratigraphic modeling may provide further quantitative control when interpreting Last Interglacial reef sequences.","PeriodicalId":48749,"journal":{"name":"Earth Surface Dynamics","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135386436","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":"Sediment source and sink identification using Sentinel-2 and a small network of turbidimeters on the Vjosa River","authors":"Jessica Droujko, Srividya Hariharan Sudha, Gabriel Singer, Peter Molnar","doi":"10.5194/esurf-11-881-2023","DOIUrl":"https://doi.org/10.5194/esurf-11-881-2023","url":null,"abstract":"Abstract. Measurement of suspended sediment concentration (SSC) at a basin outlet yields a basin-integrated picture of sediment fluxes; however, it does not give a full spatial perspective on possible sediment pathways within the catchment. Spatially resolved estimates of SSC along river networks are needed to identify sediment sources and sinks, to track erosion gradients, and quantify anthropogenic effects on catchment-scale sediment production, e.g., by dam construction or erosion control. Here we explore the use of high-resolution Sentinel-2 satellite images for this purpose in narrow and morphologically complex mountain rivers, combined with ground station turbidity sensing for calibration and supported by a Lagrangian kayak-derived river profile measurement. The study is carried out on the Vjosa River in Albania, which is one of the last intact large river systems in Europe. We developed a workflow to estimate river turbidity profiles from Sentinel-2 images including atmospheric, cloud cover, and deepwater corrections for the period May 2019 to July 2021 (106 images). In situ turbidity measurements from four turbidity sensors located along the Vjosa River provided ground truthing. A multivariate linear regression model between turbidity and reflectance was fitted to this data. The extracted longitudinal river turbidity profiles were qualitatively validated with two descents of the river with a turbidity sensor attached to a kayak. The satellite-derived river profiles revealed variability in turbidity along the main stem with a strong seasonal signal, with the highest mean turbidity in winter along the entire length of the river. Most importantly, sediment sources and sinks could be identified and quantified from the river turbidity profiles, both for tributaries and within the reaches of the Vjosa. The river basin and network acted as a sediment source most of the time and significant sediment sinks were rare. Sediment sources were mostly tributaries following basin-wide rainfall, but within-reach sources in river beds and banks were also possible. Finally, we used the data to estimate the mean annual fine sediment yield at Dorez at ∼2.5±0.6 Mt yr−1, in line with previous studies, which reveals the importance of the Vjosa River as an important sediment source of the Adriatic Sea. This work presents a proof of concept that open-access high-resolution satellite data have potential for suspended sediment quantification not only in large waterbodies but also in smaller rivers. The potential applications are many, including identifying erosion hotspots, sediment activation processes, local point sources, glacial sediment inputs, and sediment fluxes in river deltas, with a necessary future research focus on improving accuracy and reducing uncertainty in such analyses.","PeriodicalId":48749,"journal":{"name":"Earth Surface Dynamics","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135014589","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":"Estimating surface water availability in high mountain rock slopes using a numerical energy balance model","authors":"Matan Ben-Asher, Florence Magnin, Sebastian Westermann, Josué Bock, Emmanuel Malet, Johan Berthet, Ludovic Ravanel, Philip Deline","doi":"10.5194/esurf-11-899-2023","DOIUrl":"https://doi.org/10.5194/esurf-11-899-2023","url":null,"abstract":"Abstract. Water takes part in most physical processes that shape mountainous periglacial landscapes and initiation of mass-wasting processes. An observed increase in rockfall activity in high mountain regions was previously linked to permafrost degradation, and water that infiltrates into rock fractures is one of the likely drivers of processes related to thawing and destabilization. However, there is very little knowledge of the quantity and timing of water availability for infiltration into steep rock slopes. This knowledge gap originates from the complex meteorological, hydrological, and thermal processes that control snowmelt, as well as challenging access and data acquisition in extreme alpine environments. Here we use field measurements and numerical modeling to simulate the energy balance and hydrological fluxes on a steep high-elevation permafrost-affected rock slope at Aiguille du Midi (3842 m a.s.l, France), in the Mont Blanc massif. Our results provide new information about water balance at the surface of steep rock slopes. Model results suggest that only ∼ 25 % of the snowfall accumulates in our study site; the remaining ∼ 75 % is likely transported downslope by wind and gravity. The snowpack thickness was found to decrease with surface slopes between 40 and 70∘. We found that among all water fluxes, sublimation is the main process of snowpack mass loss at our study site. Snowmelt occurs between spring and late summer, but most of it may not reach the rock surface due to refreezing and the formation of an impermeable ice layer at the base of the snowpack, which was observed at the field site. The annual snowmelt that is available for infiltration (i.e., effective snowmelt) is highly variable in the simulated years 1959–2021, and its onset occurs mostly between May and August and ends before October. By applying the model to a range of altitudes, we show that effective snowmelt is the main source of water for infiltration above 3600 m a.s.l.; below, direct rainfall on the snow-free surface is the dominant source. This change from snowmelt- to rainfall-dominated water input leads to an abrupt, nonlinear increase in water availability at altitudes below 3600 m a.s.l and may point to higher sensitivity of permafrost-affected rock slopes to climate change at these altitudes.","PeriodicalId":48749,"journal":{"name":"Earth Surface Dynamics","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135014991","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}