Geomorphology最新文献_第2页

Insights into red-bed landslide movement from the perspective of geomorphic evolution: A case study in western Yunnan, China 地貌演化视角下的红层滑坡运动——以滇西地区为例

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2026-01-07 DOI: 10.1016/j.geomorph.2025.110157

Xin Zhao , Xiujun Dong , Zhifang Zhao , Zhiquan Yang , Yi Yang , Mingchun Wen , Yifan Cao

Geomorphic evolution not only records the dynamics of the Earth's surface through a cyclical progression from the youthful stage to an older stage but is also closely intertwined with the current and future development of the Earth's surface. Red-bed landslides are distributed in the red-series continental layered clastic rock formations deposited during the Mesozoic–Cenozoic Eras. Endowed with inherent susceptibility to bedding-parallel sliding and distinct morphological diversity, these landslides constitute a typical geomorphic hazard on the Earth's surface. Those slope movements are inevitably closely linked to geomorphic evolution, which serves as a crucial implicit feature of surface changes. However, the movement characteristics of red-bed landslides from the perspective of geomorphic evolution remain poorly understood, necessitating further investigation into this issue. This paper focuses on the Qinjia red-bed landslide in western Yunnan, China, which remained in a slow-moving state from June 2018 to May 2022. Our research findings were obtained through multidisciplinary approaches, including unmanned aerial vehicle (UAV)-borne light detection and ranging (LiDAR), satellite-based time-series interferometric synthetic aperture radar (InSAR), geomorphic evolution analysis, and digital terrain analysis. Both the geomorphic evolution in the temporal dimension and the surface deformation in the spatial dimension exhibit significant differential distribution characteristics on the Qinjia landslide. The coupling model of the geomorphic evolution and InSAR deformation rate conforms to a significant quadratic function relationship, meaning that as the geomorphic evolution process progresses, the deformation rate exhibits a trend of first increasing and then decreasing. Additionally, areas in the mature stage correspond to the portions where landslide movement is most intense. The spatial distribution of the geomorphic evolution progression across the secondary sliding zones reveals that the sliding pattern of the Qinjia landslide is traction-type. The results of this study supplement the mountain disaster community's understanding of the movement characteristics of landslides from the perspective of geomorphic evolution.

地貌演化不仅记录了地球表面从年轻阶段到老年阶段的周期性进展，而且与地球表面现在和未来的发展密切相关。红层滑坡分布在中新生代沉积的红系陆相层状碎屑岩中。这些滑坡具有顺层平行滑动的固有易感性和独特的形态多样性，是地球表面典型的地貌灾害。这些斜坡运动不可避免地与地貌演化密切相关，地貌演化是地表变化的一个重要隐含特征。然而，从地貌演化的角度对红层滑坡的运动特征了解甚少，需要进一步深入研究。本文以2018年6月至2022年5月处于缓慢移动状态的滇西秦家红层滑坡为研究对象。我们的研究成果是通过多学科方法获得的，包括无人机（UAV）机载光探测和测距（LiDAR）、基于卫星的时序干涉合成孔径雷达（InSAR）、地貌演变分析和数字地形分析。秦家滑坡在时间维度上的地貌演化和空间维度上的地表变形均表现出显著的差异分布特征。地貌演化与InSAR变形率的耦合模型符合显著的二次函数关系，即随着地貌演化过程的进行，变形率呈现先增大后减小的趋势。另外，处于成熟阶段的区域对应着滑坡运动最剧烈的区域。各次生滑坡带地貌演化过程的空间分布特征表明秦家滑坡为牵引型滑坡带。本研究结果补充了山地灾害学界从地貌演化角度对滑坡运动特征的认识。

{"title":"Insights into red-bed landslide movement from the perspective of geomorphic evolution: A case study in western Yunnan, China","authors":"Xin Zhao , Xiujun Dong , Zhifang Zhao , Zhiquan Yang , Yi Yang , Mingchun Wen , Yifan Cao","doi":"10.1016/j.geomorph.2025.110157","DOIUrl":"10.1016/j.geomorph.2025.110157","url":null,"abstract":"<div><div>Geomorphic evolution not only records the dynamics of the Earth's surface through a cyclical progression from the youthful stage to an older stage but is also closely intertwined with the current and future development of the Earth's surface. Red-bed landslides are distributed in the red-series continental layered clastic rock formations deposited during the Mesozoic–Cenozoic Eras. Endowed with inherent susceptibility to bedding-parallel sliding and distinct morphological diversity, these landslides constitute a typical geomorphic hazard on the Earth's surface. Those slope movements are inevitably closely linked to geomorphic evolution, which serves as a crucial implicit feature of surface changes. However, the movement characteristics of red-bed landslides from the perspective of geomorphic evolution remain poorly understood, necessitating further investigation into this issue. This paper focuses on the Qinjia red-bed landslide in western Yunnan, China, which remained in a slow-moving state from June 2018 to May 2022. Our research findings were obtained through multidisciplinary approaches, including unmanned aerial vehicle (UAV)-borne light detection and ranging (LiDAR), satellite-based time-series interferometric synthetic aperture radar (InSAR), geomorphic evolution analysis, and digital terrain analysis. Both the geomorphic evolution in the temporal dimension and the surface deformation in the spatial dimension exhibit significant differential distribution characteristics on the Qinjia landslide. The coupling model of the geomorphic evolution and InSAR deformation rate conforms to a significant quadratic function relationship, meaning that as the geomorphic evolution process progresses, the deformation rate exhibits a trend of first increasing and then decreasing. Additionally, areas in the mature stage correspond to the portions where landslide movement is most intense. The spatial distribution of the geomorphic evolution progression across the secondary sliding zones reveals that the sliding pattern of the Qinjia landslide is traction-type. The results of this study supplement the mountain disaster community's understanding of the movement characteristics of landslides from the perspective of geomorphic evolution.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"496 ","pages":"Article 110157"},"PeriodicalIF":3.1,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145929266","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}

引用次数: 0

Quantifying the influencing factors on the spatiotemporal patterns of dune activity in the Tengger Desert, Northwestern China 腾格里沙漠沙丘活动时空格局影响因素量化研究

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2026-01-06 DOI: 10.1016/j.geomorph.2025.110154

Xuehua Che, Zhuolun Li, Shipei Dong, Jie Luo, Yingyibing Shen, Xue Peng

Eolian dunes are sedimentary landforms that are particularly sensitive to climate change. Dune activity, including dune migration and sand transport, responds rapidly to environmental changes. However, the contribution of environmental factors underlying spatial variations in dune activity remains unclear. To address this issue, we quantify dune activity in the Tengger Desert and assess the dominant influences including: sand supply, vegetation, topography, and climate. In this study, based on Landsat imagery and COSI-Corr technique, we first derive the spatiotemporal characteristics of the dune migration and sand transport flux in the Tengger Desert from 2014 to 2023, then the dominant factors governing dune activity are identified using the Random Forest (RF) model. The results show that the average dune migration rate in the Tengger Desert is 2.1–3.7 m/yr, with a migration direction of ESE-SSE. The average sand transport flux in the desert is 18.89 ± 28.61 m³/m/yr, controlled by a combination of wind energy and sediment availability. Overall, precipitation, wind intensity, topographic relief, and vegetation coverage are the primary controls on dune activity. In regions with annual precipitation below 150 mm, low precipitation plays a dominant role in dune activity. In regions with precipitation exceeding 150 mm, wind intensity and vegetation coverage become the primary controls, leading to the formation of bistable dune landscapes. This study clarifies the dominant factors affecting changes in dune migration and sand flux at the dune scale, which is helpful for understanding desert evolution responding to climate change.

风成沙丘是对气候变化特别敏感的沉积地貌。沙丘活动，包括沙丘迁移和沙输运，对环境变化反应迅速。然而，环境因子对沙丘活动空间变化的影响尚不清楚。为了解决这一问题，我们量化了腾格里沙漠的沙丘活动，并评估了主要影响因素，包括：沙源、植被、地形和气候。基于Landsat影像和cos - corr技术，研究了2014 - 2023年腾格里沙漠沙丘迁移和输沙通量的时空特征，并利用随机森林（Random Forest， RF）模型识别了沙丘活动的主导因子。结果表明：腾格里沙漠沙丘平均迁移速率为2.1 ~ 3.7 m/yr，迁移方向为ESE-SSE；沙漠输沙通量平均为18.89±28.61 m3/m/yr，受风能和泥沙可利用性共同控制。总体而言，降水、风强度、地形起伏和植被覆盖是沙丘活动的主要控制因素。在年降水量小于150mm的地区，低降水对沙丘活动起主导作用。在降水量超过150 mm的地区，风强度和植被盖度成为主要控制因素，形成双稳型沙丘景观。本研究阐明了沙丘尺度上影响沙丘迁移和沙通量变化的主导因素，有助于理解气候变化对沙漠演化的响应。

{"title":"Quantifying the influencing factors on the spatiotemporal patterns of dune activity in the Tengger Desert, Northwestern China","authors":"Xuehua Che, Zhuolun Li, Shipei Dong, Jie Luo, Yingyibing Shen, Xue Peng","doi":"10.1016/j.geomorph.2025.110154","DOIUrl":"10.1016/j.geomorph.2025.110154","url":null,"abstract":"<div><div>Eolian dunes are sedimentary landforms that are particularly sensitive to climate change. Dune activity, including dune migration and sand transport, responds rapidly to environmental changes. However, the contribution of environmental factors underlying spatial variations in dune activity remains unclear. To address this issue, we quantify dune activity in the Tengger Desert and assess the dominant influences including: sand supply, vegetation, topography, and climate. In this study, based on Landsat imagery and COSI-Corr technique, we first derive the spatiotemporal characteristics of the dune migration and sand transport flux in the Tengger Desert from 2014 to 2023, then the dominant factors governing dune activity are identified using the Random Forest (RF) model. The results show that the average dune migration rate in the Tengger Desert is 2.1–3.7 m/yr, with a migration direction of ESE-SSE. The average sand transport flux in the desert is 18.89 ± 28.61 m<sup>3</sup>/m/yr, controlled by a combination of wind energy and sediment availability. Overall, precipitation, wind intensity, topographic relief, and vegetation coverage are the primary controls on dune activity. In regions with annual precipitation below 150 mm, low precipitation plays a dominant role in dune activity. In regions with precipitation exceeding 150 mm, wind intensity and vegetation coverage become the primary controls, leading to the formation of bistable dune landscapes. This study clarifies the dominant factors affecting changes in dune migration and sand flux at the dune scale, which is helpful for understanding desert evolution responding to climate change.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"496 ","pages":"Article 110154"},"PeriodicalIF":3.1,"publicationDate":"2026-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145903968","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}

引用次数: 0

Sediment yield assessment of a small ungauged montane catchment in the North Caucasus 北高加索山区一个小型未测量集水区的产沙量评估

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2026-01-05 DOI: 10.1016/j.geomorph.2025.110156

Anatoly Tsyplenkov , Maksim Uspenskii , Sergey Kharchenko , Simon Scheper , Valentin Golosov

Mountain catchments face severe erosion processes, yet sediment transport is rarely measured. Independent methods are needed to assess sediment yield without relying on long-term gauging data. We applied three methods to estimate erosion rates and sediment yield from a 1.84 km² montane catchment located in the North Caucasus. These were: 1) in-situ measurement of the lake sedimentation rate; 2) assessment of erosion rates based on the spatial distribution of geomorphic processes, their rates, and sediment connectivity; and 3) adaptation of the RUSLE model for predicting mean annual soil loss. Based on lake sedimentation rates, the mean annual area-specific sediment yield was 513 t km⁻² yr⁻¹. The spatial distribution and rates of erosion processes indicated that surficial erosion accounts for approximately 83 % of total sediment export, ephemeral streams for 7 %, and rockfalls for 6 %. The remaining contribution comes from soil creep and seasonal solifluction. The RUSLE model, coupled with the morphometric sediment delivery ratio, produced similar, yet 16 % lower, estimates of mean annual sediment yield. This suggests the potential application of this empirical model for ungauged basins in similar montane environments.

山区集水区面临着严重的侵蚀过程，但沉积物的运输很少被测量。需要独立的方法来评估产沙量，而不依赖于长期的测量数据。我们应用了三种方法来估算北高加索地区1.84 km2山地流域的侵蚀速率和产沙量。这包括：1)湖泊沉积速率的原位测量；2)基于地貌过程空间分布、速率和泥沙连通性的侵蚀速率评估；3) RUSLE模型在年平均土壤流失量预测中的应用。基于湖泊沉积速率，平均年面积产沙量为513 t km−2 yr−1。侵蚀过程的空间分布和速率表明，地表侵蚀约占总输沙量的83%，短暂河流约占7%，落石约占6%。其余的贡献来自土壤蠕变和季节性固结。RUSLE模型与形态泥沙输送比相结合，得出了相似的年平均泥沙产出量，但比前者低16%。这表明该经验模型在类似山地环境的未测量盆地中具有潜在的应用价值。

{"title":"Sediment yield assessment of a small ungauged montane catchment in the North Caucasus","authors":"Anatoly Tsyplenkov , Maksim Uspenskii , Sergey Kharchenko , Simon Scheper , Valentin Golosov","doi":"10.1016/j.geomorph.2025.110156","DOIUrl":"10.1016/j.geomorph.2025.110156","url":null,"abstract":"<div><div>Mountain catchments face severe erosion processes, yet sediment transport is rarely measured. Independent methods are needed to assess sediment yield without relying on long-term gauging data. We applied three methods to estimate erosion rates and sediment yield from a 1.84 km<sup>2</sup> montane catchment located in the North Caucasus. These were: 1) in-situ measurement of the lake sedimentation rate; 2) assessment of erosion rates based on the spatial distribution of geomorphic processes, their rates, and sediment connectivity; and 3) adaptation of the RUSLE model for predicting mean annual soil loss. Based on lake sedimentation rates, the mean annual area-specific sediment yield was 513 t km<sup>−2</sup> yr<sup>−1</sup>. The spatial distribution and rates of erosion processes indicated that surficial erosion accounts for approximately 83 % of total sediment export, ephemeral streams for 7 %, and rockfalls for 6 %. The remaining contribution comes from soil creep and seasonal solifluction. The RUSLE model, coupled with the morphometric sediment delivery ratio, produced similar, yet 16 % lower, estimates of mean annual sediment yield. This suggests the potential application of this empirical model for ungauged basins in similar montane environments.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"496 ","pages":"Article 110156"},"PeriodicalIF":3.1,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145929264","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}

引用次数: 0

Subsurface variability of sandy coastal geosystems revealed by integrated georadar and cone penetrating testing approach: Insights from the Pays-de-Monts coast (Atlantic France) 综合地质雷达和锥穿测试方法揭示的砂质海岸地质系统的地下变动性：来自Pays-de-Monts海岸（大西洋法国）的见解

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2026-01-04 DOI: 10.1016/j.geomorph.2025.110153

Julie Billy , Vivien Baudouin , Gildas Noury , Manuel Garcin

Beneath dune fields, the subsurface geology of sandy coastal systems can provide valuable insights for understanding coastal environment. While sandy coasts are often described and monitored through surface geomorphology, their internal structure and geotechnical properties remain poorly documented. To address this limitation, a combined ground-penetrating radar (GPR) and cone penetration testing (CPT) approach was applied along the Pays-de-Monts coast (Atlantic France). This multidisciplinary methodology yields complementary information on the internal architecture, stratigraphic variability, and soil behavior of coastal deposits.

Two sectors were investigated, both characterized by dune fields underlain by fractured limestone and bordered inland by low-lying marshes. Despite their apparent similarities, the sites reveal distinct features. Results provide new insights into (i) the sedimentary units anchoring the sandy coastline, (ii) the connection with adjacent marshes and low-lying environments, (iii) the relationships between dune systems and underlying deposits, and (iv) soil behavior properties linked to depositional environment or dune types themself.

From these findings, two conceptual models are proposed: (1) a prograding sandy coastline with an inland marshward transition overlain by dune field (La Parée Grollier, northern sector), and (2) a channel-fill and spit development sequence overlain by dunes (La Pège-Les 60 Bornes, southern sector). These results demonstrate the value of integrating geophysical and geotechnical methods to improve understanding of coastal geosystems and enabling the identification of site-specific characteristics. More broadly, this study demonstrates and discusses the benefits of integrating GPR-CPT approach for advancing coastal geology and highlights the relevance of local geological models for management and adaptation strategies under climate change.

在沙丘场之下，砂质海岸系统的地下地质可以为理解海岸环境提供有价值的见解。虽然沙质海岸通常是通过地表地貌学来描述和监测的，但它们的内部结构和岩土力学特性仍然缺乏文献记录。为了解决这一问题，在Pays-de-Monts海岸（法国大西洋地区）采用了探地雷达（GPR）和锥形穿透测试（CPT）相结合的方法。这种多学科的方法产生了关于海岸沉积物的内部结构、地层变异性和土壤行为的补充信息。研究人员对两个区域进行了调查，它们的特点都是沙丘区，下面是破碎的石灰岩，内陆与低洼的沼泽接壤。尽管它们有明显的相似之处，但它们的特点却截然不同。研究结果为以下方面提供了新的见解：(i)锚定砂质海岸线的沉积单元，（ii）与邻近沼泽和低洼环境的联系，（iii）沙丘系统与下伏沉积物之间的关系，以及（iv）与沉积环境或沙丘类型本身相关的土壤行为特性。在此基础上，本文提出了两个概念模型：(1)北部La par e Grollier段沙质海岸线的内陆向沼泽过渡，覆盖在沙丘上；(2)南部La p - les 60 Bornes段，覆盖在沙丘上的河道填沙和沙咀发育序列。这些结果表明，将地球物理和岩土工程方法结合起来，可以提高对沿海地质系统的理解，并能够识别特定地点的特征。更广泛地说，本研究展示并讨论了整合GPR-CPT方法对推进沿海地质学的好处，并强调了气候变化下当地地质模型对管理和适应战略的相关性。

{"title":"Subsurface variability of sandy coastal geosystems revealed by integrated georadar and cone penetrating testing approach: Insights from the Pays-de-Monts coast (Atlantic France)","authors":"Julie Billy , Vivien Baudouin , Gildas Noury , Manuel Garcin","doi":"10.1016/j.geomorph.2025.110153","DOIUrl":"10.1016/j.geomorph.2025.110153","url":null,"abstract":"<div><div>Beneath dune fields, the subsurface geology of sandy coastal systems can provide valuable insights for understanding coastal environment. While sandy coasts are often described and monitored through surface geomorphology, their internal structure and geotechnical properties remain poorly documented. To address this limitation, a combined ground-penetrating radar (GPR) and cone penetration testing (CPT) approach was applied along the Pays-de-Monts coast (Atlantic France). This multidisciplinary methodology yields complementary information on the internal architecture, stratigraphic variability, and soil behavior of coastal deposits.</div><div>Two sectors were investigated, both characterized by dune fields underlain by fractured limestone and bordered inland by low-lying marshes. Despite their apparent similarities, the sites reveal distinct features. Results provide new insights into (i) the sedimentary units anchoring the sandy coastline, (ii) the connection with adjacent marshes and low-lying environments, (iii) the relationships between dune systems and underlying deposits, and (iv) soil behavior properties linked to depositional environment or dune types themself.</div><div>From these findings, two conceptual models are proposed: (1) a prograding sandy coastline with an inland marshward transition overlain by dune field (La Parée Grollier, northern sector), and (2) a channel-fill and spit development sequence overlain by dunes (La Pège-Les 60 Bornes, southern sector). These results demonstrate the value of integrating geophysical and geotechnical methods to improve understanding of coastal geosystems and enabling the identification of site-specific characteristics. More broadly, this study demonstrates and discusses the benefits of integrating GPR-CPT approach for advancing coastal geology and highlights the relevance of local geological models for management and adaptation strategies under climate change.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"496 ","pages":"Article 110153"},"PeriodicalIF":3.1,"publicationDate":"2026-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145980507","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}

引用次数: 0

Decoding bed armoring: A predictive method for grain size distribution in sand–gravel bed rivers 解码河床盔甲：砂砾河床河流粒度分布的预测方法

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2026-01-03 DOI: 10.1016/j.geomorph.2025.110152

Zhiyi Feng , Chunhong Hu , Anjun Deng , Chenge An , Maohua Le , Ruiru Lv

Sand–gravel riverbeds downstream of hydraulic projects frequently undergo significant bed armoring. Accurately predicting the grain-size distribution of the armored layer remains a critical yet complex challenge within the field of fluvial dynamics. This study focuses on the response mechanism that connects the progressive reduction in fine sediment content with the evolution of hiding–exposure effects, the consequent alterations in sediment state transition probability, and the subsequent adjustment of the armoring rate during the process of riverbed armoring. An expression for sediment entrainment probability is derived under dynamically varying conditions, which include armoring intensity and the hiding–exposure effects of non-uniform sediments. A three-state exchange mechanism among suspended load, bed load, and bed surface material is integrated into the armoring calculation process. A sediment mass conservation relation under depositional conditions is also formulated, leading to the proposal of a novel stability criterion for bed armoring. Building on these advancements, a predictive method for determining the grain-size distribution of armored layers is developed, explicitly considering sediment exchange processes. Application of this method to the downstream reaches of the Danjiangkou and Three Gorges Reservoirs in China reveals that the predicted grain-size distribution of the armored layer deviates from field measurements by only 2.9 % on average, and from flume experiments by 4.1 %. The findings indicate that the proposed method effectively replicates gradation trends, grain-size distributions of armor layer, and scour depths under clear-water conditions. Furthermore, within the research framework of multi-stage armoring, characterized by the cyclic “formation–destruction–reformation” of armor layers, the method demonstrates considerable potential for applicability.

水利工程下游的砂砾河床经常发生明显的河床铠装。在河流动力学领域，准确预测装甲层的粒度分布仍然是一个关键而复杂的挑战。重点研究了河床成甲过程中细沙含量的逐渐减少与隐藏-暴露效应演化的响应机制，以及由此引起的泥沙状态转变概率的变化，以及随后对成甲速率的调整。导出了动态变化条件下的挟沙概率表达式，包括装甲强度和非均匀沉积物的隐藏-暴露效应。将悬架载荷、床面载荷和床面材料的三态交换机制集成到装甲计算过程中。建立了沉积条件下的沉积物质量守恒关系，从而提出了一种新的床层装甲稳定性判据。在这些进展的基础上，开发了一种确定装甲层粒度分布的预测方法，明确考虑了沉积物交换过程。将该方法应用于丹江口和三峡水库下游，结果表明，预测的甲层粒度分布与实测平均偏差仅为2.9%，与水槽试验平均偏差为4.1%。结果表明，该方法有效地模拟了清水条件下甲壳层的级配趋势、粒度分布和冲刷深度。此外，在以装甲层形成-破坏-改造为循环特征的多级装甲研究框架中，该方法显示出相当大的适用性潜力。

{"title":"Decoding bed armoring: A predictive method for grain size distribution in sand–gravel bed rivers","authors":"Zhiyi Feng , Chunhong Hu , Anjun Deng , Chenge An , Maohua Le , Ruiru Lv","doi":"10.1016/j.geomorph.2025.110152","DOIUrl":"10.1016/j.geomorph.2025.110152","url":null,"abstract":"<div><div>Sand–gravel riverbeds downstream of hydraulic projects frequently undergo significant bed armoring. Accurately predicting the grain-size distribution of the armored layer remains a critical yet complex challenge within the field of fluvial dynamics. This study focuses on the response mechanism that connects the progressive reduction in fine sediment content with the evolution of hiding–exposure effects, the consequent alterations in sediment state transition probability, and the subsequent adjustment of the armoring rate during the process of riverbed armoring. An expression for sediment entrainment probability is derived under dynamically varying conditions, which include armoring intensity and the hiding–exposure effects of non-uniform sediments. A three-state exchange mechanism among suspended load, bed load, and bed surface material is integrated into the armoring calculation process. A sediment mass conservation relation under depositional conditions is also formulated, leading to the proposal of a novel stability criterion for bed armoring. Building on these advancements, a predictive method for determining the grain-size distribution of armored layers is developed, explicitly considering sediment exchange processes. Application of this method to the downstream reaches of the Danjiangkou and Three Gorges Reservoirs in China reveals that the predicted grain-size distribution of the armored layer deviates from field measurements by only 2.9 % on average, and from flume experiments by 4.1 %. The findings indicate that the proposed method effectively replicates gradation trends, grain-size distributions of armor layer, and scour depths under clear-water conditions. Furthermore, within the research framework of multi-stage armoring, characterized by the cyclic “formation–destruction–reformation” of armor layers, the method demonstrates considerable potential for applicability.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"496 ","pages":"Article 110152"},"PeriodicalIF":3.1,"publicationDate":"2026-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145929263","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}

引用次数: 0

Gully erosion susceptibility assessment and SHAP interpretability analysis in sloping farmland of soil-rock dual structure area: A case study of Yimeng Mountain area, China 土石二元结构区坡耕地沟沟侵蚀敏感性评价及SHAP可解释性分析——以沂蒙山区为例

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2025-12-30 DOI: 10.1016/j.geomorph.2025.110146

Ziming Zheng , Tingting Yan , Weijun Zhao , Wei Qin , Chunyang Huang , Yi Wang , Zhen Li

Gully erosion, as a typical form of hydraulic erosion, is a major driver of soil degradation on sloping farmland and poses a serious threat to agricultural production and food security. Accurate and automated identification of gully erosion susceptibility (GES) therefore remains an urgent challenge. In regions with a soil-rock dual structure, soils are thin, heterogeneous, and weakly developed, and gully erosion is highly prevalent. Thus, it is essential to incorporate underlying-surface factors such as rock fragment content and soil thickness into susceptibility assessment. With the Yimeng Mountain area of northern China as a case study, five modelling approaches were developed including machine learning (Random Forest, RF and eXtreme Gradient Boosting, XGBoost), multivariate regression (Logistic Regression, LR), and deep learning (Transformer and Convolutional Neural Network, CNN). SHapley Additive exPlanations (SHAP) was applied for model interpretability. The results showed that: (1) The RF model achieved the highest prediction accuracy (ACC = 0.9534, AUC = 0.9809), outperforming LR, XGBoost, CNN, and Transformer. (2) In the susceptibility map produced by integrating RF, XGBoost, and LR, high and very high susceptibility zones account for 47 % of the study area. (3) 15 influencing factors contribute to gully erosion, among which topographic wetness index (TWI), slope, and distance to rivers are the most significant drivers. Areas with high wetness (TWI > 8–10), gentle slopes (10–15°), and proximity to rivers (<2000 m) exhibit a high likelihood of gully initiation and development. Under deep soil conditions, the combination of high TWI and short distances to rivers strongly promotes gully erosion, whereas higher rock fragment content on steep slopes helps to inhibit it. By automatically generating gully erosion susceptibility maps (GESMs), this study effectively identifies high-risk zones for gully initiation and expansion, providing robust scientific support for gully erosion control, farmland protection, land-use management, and sustainable agricultural development.

沟沟侵蚀作为一种典型的水力侵蚀形式，是坡耕地土壤退化的主要驱动因素，对农业生产和粮食安全构成严重威胁。因此，沟蚀敏感性的准确和自动识别仍然是一个紧迫的挑战。在土岩二元结构地区，土壤较薄、不均匀、发育较弱，沟壑侵蚀较为普遍。因此，将岩石破碎块含量、土壤厚度等下垫面因素纳入敏感性评价中是十分必要的。以中国北方沂蒙山地区为例，开发了五种建模方法，包括机器学习（随机森林，RF和极端梯度增强，XGBoost），多元回归（Logistic回归，LR）和深度学习（变压器和卷积神经网络，CNN）。模型可解释性采用SHapley加性解释（SHAP）。结果表明：(1)射频模型的预测精度最高（ACC = 0.9534, AUC = 0.9809），优于LR、XGBoost、CNN和Transformer。(2)在RF、XGBoost和LR综合绘制的敏感性图中，高和极高敏感性区占研究区面积的47%。(3) 15个影响因子对沟道侵蚀有影响，其中地形湿度指数（TWI）、坡度和与河流的距离是最显著的驱动因子。高湿度（TWI > 8-10）、缓坡（10-15°）和靠近河流（<2000 m）的地区极有可能出现沟壑的形成和发展。在深土条件下，高TWI和距离河流较近的组合强烈地促进了沟蚀，而陡坡上较高的岩屑含量有助于抑制沟蚀。该研究通过自动生成沟蚀敏感性图（GESMs），有效识别沟蚀形成和扩展的高发区，为沟蚀治理、农田保护、土地利用管理和农业可持续发展提供有力的科学支持。

{"title":"Gully erosion susceptibility assessment and SHAP interpretability analysis in sloping farmland of soil-rock dual structure area: A case study of Yimeng Mountain area, China","authors":"Ziming Zheng , Tingting Yan , Weijun Zhao , Wei Qin , Chunyang Huang , Yi Wang , Zhen Li","doi":"10.1016/j.geomorph.2025.110146","DOIUrl":"10.1016/j.geomorph.2025.110146","url":null,"abstract":"<div><div>Gully erosion, as a typical form of hydraulic erosion, is a major driver of soil degradation on sloping farmland and poses a serious threat to agricultural production and food security. Accurate and automated identification of gully erosion susceptibility (GES) therefore remains an urgent challenge. In regions with a soil-rock dual structure, soils are thin, heterogeneous, and weakly developed, and gully erosion is highly prevalent. Thus, it is essential to incorporate underlying-surface factors such as rock fragment content and soil thickness into susceptibility assessment. With the Yimeng Mountain area of northern China as a case study, five modelling approaches were developed including machine learning (Random Forest, RF and eXtreme Gradient Boosting, XGBoost), multivariate regression (Logistic Regression, LR), and deep learning (Transformer and Convolutional Neural Network, CNN). SHapley Additive exPlanations (SHAP) was applied for model interpretability. The results showed that: (1) The RF model achieved the highest prediction accuracy (ACC = 0.9534, AUC = 0.9809), outperforming LR, XGBoost, CNN, and Transformer. (2) In the susceptibility map produced by integrating RF, XGBoost, and LR, high and very high susceptibility zones account for 47 % of the study area. (3) 15 influencing factors contribute to gully erosion, among which topographic wetness index (TWI), slope, and distance to rivers are the most significant drivers. Areas with high wetness (TWI > 8–10), gentle slopes (10–15°), and proximity to rivers (<2000 m) exhibit a high likelihood of gully initiation and development. Under deep soil conditions, the combination of high TWI and short distances to rivers strongly promotes gully erosion, whereas higher rock fragment content on steep slopes helps to inhibit it. By automatically generating gully erosion susceptibility maps (GESMs), this study effectively identifies high-risk zones for gully initiation and expansion, providing robust scientific support for gully erosion control, farmland protection, land-use management, and sustainable agricultural development.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"496 ","pages":"Article 110146"},"PeriodicalIF":3.1,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145929265","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}

引用次数: 0

Evaluating long-term geomorphic responses and sediment budget impacts of threshold-based floods and sediment replenishment in the Naka River, Japan 基于阈值的洪水和沉积物补给对日本中江长期地貌响应和泥沙收支影响的评估

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2025-12-30 DOI: 10.1016/j.geomorph.2025.110150

Cheng Wei , Sameh A. Kantoush , Binh Quang Nguyen , Sohei Kobayashi , Jia Qi Lin , Tetsuya Sumi

Quantifying the geomorphic effectiveness of sediment replenishment (SR) in restoring riverine sediment continuity remains challenging under variable flow regimes in dam-regulated systems. This study investigates downstream sediment dynamics in the Naka River, Japan, by integrating threshold-based flood frequency analysis (Peak-Over-Threshold, POT), sediment grain size measurements for tracking the sediment source from the SR site, and multitemporal geomorphic change detection (GCD) between 2010 and 2015. An optimal discharge threshold of 357.55 m³/s was identified to delineate geomorphically significant flows, including the extreme 2014 event (5411 m³/s; 134-year return period), which drove substantial geomorphic change. Difference of Digital Elevation Models (DoD) of the bathymetric channel (period 2010–2011, 2011–2012, …, 2014–2015, and 2010–2015) revealed incision at the SR site (up to −0.89 m) and downstream aggradation (up to +0.65 m) in the meandering mid-reach (7–14 km), evidencing sediment dispersal from the replenishment site. Sediment budgets indicated peak gross erosion (27.98 Mm³) during 2013–2014, followed by stabilization. Cross-sectional analyses confirmed outer-bend erosion and inner-bend deposition, reflecting natural meander dynamics, while episodic reappearance of coarse grains in 2013 and 2017 suggested localized re-exposure or flood-driven remobilization. Sediment transport and deposition were strongly influenced by local channel curvature and typhoon-induced flows, with limited morphological change beyond 14 km due to Kawaguchi Dam backwater effects. This integrated POT–GCD approach effectively identifies geomorphically significant floods and quantifies their spatial influence, demonstrating that SR enhances downstream sediment delivery and channel adjustment, emphasizing the role of hydrology and sediment connectivity in restoring riverine sediment budgets.

量化泥沙补给（SR）在恢复河流泥沙连续性中的地貌有效性仍然具有挑战性。本研究采用基于阈值的洪水频率分析（Peak-Over-Threshold， POT）、沉积物粒度测量（用于追踪SR站点的沉积物来源）和2010 - 2015年间的多时段地貌变化检测（GCD），对日本Naka河下游的泥沙动态进行了研究。确定了357.55 m3/s的最佳流量阈值，以描绘具有地貌意义的流量，包括2014年的极端事件（5411 m3/s， 134年的重现期），该事件导致了实质性的地貌变化。2010-2011年、2011-2012年、2011-2012年、2014-2015年和2010-2015年等深河道的数字高程模型（DoD）的差异显示，在蜿蜒的中游（7-14 km），泥沙从补给点扩散，在SR位置有切口（最大达- 0.89 m），下游有堆积（最大达+0.65 m）。泥沙收支表明，总侵蚀在2013-2014年达到峰值（27.98 Mm3），随后趋于稳定。横断面分析证实了外弯侵蚀和内弯沉积，反映了自然曲流动力学，而2013年和2017年粗粮的间歇性再现表明局部再暴露或洪水驱动的再动员。输沙和沉积受局地河道曲率和台风流的强烈影响，14 km以外受川口坝回水影响的形态变化有限。这种综合的POT-GCD方法有效地识别了具有地貌意义的洪水，并量化了它们的空间影响，表明SR增强了下游输沙量和河道调整，强调了水文和泥沙连通性在恢复河流泥沙收支中的作用。

{"title":"Evaluating long-term geomorphic responses and sediment budget impacts of threshold-based floods and sediment replenishment in the Naka River, Japan","authors":"Cheng Wei , Sameh A. Kantoush , Binh Quang Nguyen , Sohei Kobayashi , Jia Qi Lin , Tetsuya Sumi","doi":"10.1016/j.geomorph.2025.110150","DOIUrl":"10.1016/j.geomorph.2025.110150","url":null,"abstract":"<div><div>Quantifying the geomorphic effectiveness of sediment replenishment (SR) in restoring riverine sediment continuity remains challenging under variable flow regimes in dam-regulated systems. This study investigates downstream sediment dynamics in the Naka River, Japan, by integrating threshold-based flood frequency analysis (Peak-Over-Threshold, POT), sediment grain size measurements for tracking the sediment source from the SR site, and multitemporal geomorphic change detection (GCD) between 2010 and 2015. An optimal discharge threshold of 357.55 m<sup>3</sup>/s was identified to delineate geomorphically significant flows, including the extreme 2014 event (5411 m<sup>3</sup>/s; 134-year return period), which drove substantial geomorphic change. Difference of Digital Elevation Models (DoD) of the bathymetric channel (period 2010–2011, 2011–2012, …, 2014–2015, and 2010–2015) revealed incision at the SR site (up to −0.89 m) and downstream aggradation (up to +0.65 m) in the meandering mid-reach (7–14 km), evidencing sediment dispersal from the replenishment site. Sediment budgets indicated peak gross erosion (27.98 Mm<sup>3</sup>) during 2013–2014, followed by stabilization. Cross-sectional analyses confirmed outer-bend erosion and inner-bend deposition, reflecting natural meander dynamics, while episodic reappearance of coarse grains in 2013 and 2017 suggested localized re-exposure or flood-driven remobilization. Sediment transport and deposition were strongly influenced by local channel curvature and typhoon-induced flows, with limited morphological change beyond 14 km due to Kawaguchi Dam backwater effects. This integrated POT–GCD approach effectively identifies geomorphically significant floods and quantifies their spatial influence, demonstrating that SR enhances downstream sediment delivery and channel adjustment, emphasizing the role of hydrology and sediment connectivity in restoring riverine sediment budgets.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"496 ","pages":"Article 110150"},"PeriodicalIF":3.1,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145903960","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}

引用次数: 0

Temporal and spatial dynamics of urban stream geomorphology: The role of effective imperviousness and development age 城市水系地貌的时空动态：有效不透水性和发展年龄的作用

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2025-12-30 DOI: 10.1016/j.geomorph.2025.110155

Lukman A. Soboyejo , Kathryn L. Russell , Tim D. Fletcher

Urbanisation has been widely studied for its impact on stream channel geomorphology, primarily using space-for-time substitution approaches. However, continuous monitoring of urban geomorphic responses, to understand the temporal dynamics and influence of development age, remains underexplored within this framework. In this study, we combined repeated field observations collected 13 years apart with land cover analysis to assess geomorphic change across a gradient of urbanisation. We addressed three research questions: (i) to what extent do space-for-time substitution interpretations align with directly observed changes in stream channel morphology, and are post-study changes in stream channels consistent with earlier observations? (ii) how has the change in the extent of urbanisation over the study period directly influenced observed changes in stream channel morphology? (iii) at what level of urban development is stream incision most severe (i.e., does channel morphology stabilise during the latter stages of urban development)? We found that predictions made through space-for-time substitution in 2011 (i.e. regression models) were largely consistent with relationships observed in 2024 following further urbanisation of the catchments. However, change in geomorphic attributes at each site over the 13-year period were not significantly related to change in effective impervious cover (EI), possibly due to lag in geomorphic responses to ongoing urbanisation, along with the presence of hardpoints such as rock protection in the urbanised streams. Notably, several individual sites did show signs of active channel adjustment; all of these sites had moderate levels of urbanisation (<30 % EI), which had developed relatively recently (in the last 25 years). Severe channel incision was also observed within this range, suggesting a critical window for morphological instability. Whether channels eventually stabilise (without heavy intervention to harden channels) remains uncertain. Overall, the findings reinforce the importance of validating space-for-time substitution approaches through repeated observations to better develop more reliable urban channel evolution and stream management strategies.

城市化对河道地貌的影响已被广泛研究，主要采用时空替代方法。然而，在这一框架内，对城市地貌响应的持续监测，以了解发展年龄的时间动态和影响，仍未得到充分探索。在这项研究中，我们将相隔13年的重复实地观测与土地覆盖分析相结合，以评估城市化梯度下的地貌变化。我们解决了三个研究问题：(i)时空替代解释在多大程度上与直接观察到的河流河道形态变化相一致，以及研究后的河流河道变化与早期观察结果一致？（ii）在研究期间，城市化程度的变化如何直接影响已观察到的河道形态变化？（iii）在城市发展的哪个阶段，河流切割最为严重（即，在城市发展的后期，河道形态是否趋于稳定）？我们发现，2011年通过时空替代（即回归模型）所做的预测与流域进一步城市化后2024年观察到的关系基本一致。然而，在13年的时间里，每个地点的地貌属性变化与有效不透水覆盖（EI）的变化没有显著相关性，这可能是由于地貌对持续城市化的响应滞后，以及城市化溪流中存在岩石保护等挂载点。值得注意的是，几个单独的网站确实显示出积极的渠道调整迹象；所有这些地点都有中等水平的城市化（30% EI），这些城市化发展相对较晚（过去25年）。在这个范围内也观察到严重的通道切口，提示形态不稳定的关键窗口。渠道最终是否会稳定（不需要大量干预来强化渠道）仍不确定。总的来说，研究结果强调了通过反复观察验证空间替代时间方法的重要性，以更好地制定更可靠的城市通道演变和流管理策略。

{"title":"Temporal and spatial dynamics of urban stream geomorphology: The role of effective imperviousness and development age","authors":"Lukman A. Soboyejo , Kathryn L. Russell , Tim D. Fletcher","doi":"10.1016/j.geomorph.2025.110155","DOIUrl":"10.1016/j.geomorph.2025.110155","url":null,"abstract":"<div><div>Urbanisation has been widely studied for its impact on stream channel geomorphology, primarily using space-for-time substitution approaches. However, continuous monitoring of urban geomorphic responses, to understand the temporal dynamics and influence of development age, remains underexplored within this framework. In this study, we combined repeated field observations collected 13 years apart with land cover analysis to assess geomorphic change across a gradient of urbanisation. We addressed three research questions: (i) to what extent do space-for-time substitution interpretations align with directly observed changes in stream channel morphology, and are post-study changes in stream channels consistent with earlier observations? (ii) how has the change in the extent of urbanisation over the study period directly influenced observed changes in stream channel morphology? (iii) at what level of urban development is stream incision most severe (i.e., does channel morphology stabilise during the latter stages of urban development)? We found that predictions made through space-for-time substitution in 2011 (i.e. regression models) were largely consistent with relationships observed in 2024 following further urbanisation of the catchments. However, change in geomorphic attributes at each site over the 13-year period were not significantly related to change in effective impervious cover (EI), possibly due to lag in geomorphic responses to ongoing urbanisation, along with the presence of hardpoints such as rock protection in the urbanised streams. Notably, several individual sites did show signs of active channel adjustment; all of these sites had moderate levels of urbanisation (<30 % EI), which had developed relatively recently (in the last 25 years). Severe channel incision was also observed within this range, suggesting a critical window for morphological instability. Whether channels eventually stabilise (without heavy intervention to harden channels) remains uncertain. Overall, the findings reinforce the importance of validating space-for-time substitution approaches through repeated observations to better develop more reliable urban channel evolution and stream management strategies.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"495 ","pages":"Article 110155"},"PeriodicalIF":3.1,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884362","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}

引用次数: 0

Identifying gravel-sand transition zones in alluvial plains using normalized steepness index 利用归一化坡度指数识别冲积平原砂砾-砂过渡带

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2025-12-29 DOI: 10.1016/j.geomorph.2025.110151

Kazuki Yoshida , Mamoru Koarai

Identifying gravel-sand transition (GST) location, where riverbed sediments shift from coarse gravel to fine sandy-muddy materials, is crucial for assessing natural disaster risk. However, GST zones remain unidentified on Japan's landform classification maps, complicating disaster risk assessments. Therefore, here, we aimed to investigate differences in the formation zones of gravelly and sandy-muddy alluvial plains in Japan, and GST zones in previous studies both within and outside Japan. To this end, we analyzed the longitudinal valley slope (S) and upstream drainage area (A) of 118 rivers in median- to large-scale alluvial plains of Japan, calculated using digital terrain models derived from Light Detection and Ranging. Sediment types from the surface to a depth of 3 m were obtained from borehole log data. Additionally, we calculated S and A values for small- to median-scale alluvial plains across six regions of Japan with different river sedimentation environments. The transition from gravelly to sandy-muddy alluvial plains systematically occurred at a normalized steepness index (k_sn) value of 10–20 m^0.9. This threshold corresponded to the observed relationship between k_sn and the median grain size of riverbed sediments: when k_sn was below 20 m^0.9, fine-grained sediments, including sand, became dominant. This threshold is consistent with GST zones reported globally. As k_sn can be derived solely from terrain data, without requiring field observations, it offers a practical method for generating simple, area-based landform classification maps. This approach is especially useful for the rapid creation of hazard maps, such as those predicting liquefaction risk.

确定砾石-砂过渡（GST）位置，即河床沉积物从粗砾石向细砂-泥质物质转变的位置，对于评估自然灾害风险至关重要。然而，在日本的地形分类地图上，商品及服务税区域仍未确定，这使灾害风险评估变得复杂。因此，在此，我们旨在研究日本砂砾质和砂质泥质冲积平原的形成带与日本国内外前人研究的GST形成带的差异。为此，我们分析了日本中尺度冲积平原118条河流的纵向河谷坡度(S)和上游流域面积(A)，并使用基于Light Detection and Ranging的数字地形模型进行了计算。利用钻孔测井资料获得了地表至3 m深度的沉积物类型。此外，我们还计算了日本6个不同河流沉积环境的小到中尺度冲积平原的S和A值。砾石冲积平原向砂质泥质冲积平原的转变系统地发生在归一化陡度指数（ksn）为10 ~ 20 m0.9的范围内。该阈值与观测到的ksn与河床沉积物中位粒径之间的关系相对应，当ksn低于20 m0.9时，细粒沉积物（包括砂）占主导地位。这一阈值与全球报告的GST区域一致。由于ksn可以完全从地形数据中获得，而不需要实地观测，因此它为生成简单的、基于区域的地形分类图提供了一种实用的方法。这种方法对于快速创建危险图特别有用，例如预测液化风险。

{"title":"Identifying gravel-sand transition zones in alluvial plains using normalized steepness index","authors":"Kazuki Yoshida , Mamoru Koarai","doi":"10.1016/j.geomorph.2025.110151","DOIUrl":"10.1016/j.geomorph.2025.110151","url":null,"abstract":"<div><div>Identifying gravel-sand transition (GST) location, where riverbed sediments shift from coarse gravel to fine sandy-muddy materials, is crucial for assessing natural disaster risk. However, GST zones remain unidentified on Japan's landform classification maps, complicating disaster risk assessments. Therefore, here, we aimed to investigate differences in the formation zones of gravelly and sandy-muddy alluvial plains in Japan, and GST zones in previous studies both within and outside Japan. To this end, we analyzed the longitudinal valley slope (<em>S</em>) and upstream drainage area (<em>A</em>) of 118 rivers in median- to large-scale alluvial plains of Japan, calculated using digital terrain models derived from Light Detection and Ranging. Sediment types from the surface to a depth of 3 m were obtained from borehole log data. Additionally, we calculated <em>S</em> and <em>A</em> values for small- to median-scale alluvial plains across six regions of Japan with different river sedimentation environments. The transition from gravelly to sandy-muddy alluvial plains systematically occurred at a normalized steepness index (<em>k</em><sub><em>sn</em></sub>) value of 10–20 m<sup>0.9</sup>. This threshold corresponded to the observed relationship between <em>k</em><sub><em>sn</em></sub> and the median grain size of riverbed sediments: when <em>k</em><sub><em>sn</em></sub> was below 20 m<sup>0.9</sup>, fine-grained sediments, including sand, became dominant. This threshold is consistent with GST zones reported globally. As <em>k</em><sub><em>sn</em></sub> can be derived solely from terrain data, without requiring field observations, it offers a practical method for generating simple, area-based landform classification maps. This approach is especially useful for the rapid creation of hazard maps, such as those predicting liquefaction risk.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"495 ","pages":"Article 110151"},"PeriodicalIF":3.1,"publicationDate":"2025-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145939275","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}

引用次数: 0

Toward an efficient framework for remote sensing of river bathymetry: Comparing sensors and algorithms on an inaccessible proglacial river in Alaska 迈向河流测深遥感的有效框架：在阿拉斯加一条难以接近的前冰川河流上比较传感器和算法

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2025-12-24 DOI: 10.1016/j.geomorph.2025.110140

Carl J. Legleiter , Christina M. Leonard , Paul A. Burger , Addison G. Pletcher , Paul J. Kinzel

Remote sensing can provide reliable information on river depths and this approach might be particularly valuable in areas that are difficult to survey via conventional field methods. In this study, we assessed the potential to map the bathymetry of an inaccessible proglacial river in Alaska from both aerial orthophotos and a multispectral satellite image. In addition, we evaluated a variety of depth retrieval algorithms with different input data requirements, including some methods that require field measurements of water depth for calibration and other techniques that can be applied even when such field data are not available. These approaches might enable more efficient use of remote sensing methods by resource management agencies. Our results suggest that bathymetric mapping along the turquoise-colored river we examined was not only feasible but highly accurate (

R^{2}

up to 0.94) for both types of image data. Algorithms that use paired observations of depth and reflectance to train depth retrieval models were the most accurate, with errors on the order of 15%–20% and little or no bias. Alternative techniques based on hydraulic and statistical concepts also led to strong agreement between predicted and observed depths but were more susceptible to systematic biases toward under- or over-estimation of depth. In contrast to clear-flowing streams, bathymetric mapping in this environment was enabled by a direct relationship between the depth and brightness of the water due to scattering by suspended sediment. In selecting an appropriate depth retrieval method, a compromise might need to be reached between the level of field effort invested and the accuracy of the resulting image-derived bathymetry. Standalone software for implementing these techniques is freely available.

遥感可以提供关于河流深度的可靠信息，这种方法在难以通过常规实地方法进行调查的地区可能特别有价值。在这项研究中，我们评估了从航空正射影像和多光谱卫星图像中绘制阿拉斯加一条难以进入的前冰川河流的测深图的潜力。此外，我们还评估了不同输入数据要求的各种深度检索算法，包括一些需要现场测量水深进行校准的方法，以及即使没有现场数据也可以应用的其他技术。这些办法可能使资源管理机构能够更有效地利用遥感方法。我们的研究结果表明，对于这两种类型的图像数据，沿着绿松石色的河流进行水深测绘不仅可行，而且精度很高（R2高达0.94）。使用深度和反射率成对观测来训练深度检索模型的算法是最准确的，误差在15%-20%之间，几乎没有偏差。基于水力和统计概念的替代技术也使预测深度和观测深度之间的一致性很强，但更容易受到对深度估计不足或过高的系统性偏差的影响。与清澈的溪流相比，由于悬浮沉积物的散射，这种环境中的水深和亮度之间的直接关系使水深测绘成为可能。在选择适当的深度检索方法时，可能需要在投入的现场工作水平和由此产生的图像衍生测深精度之间达成妥协。实现这些技术的独立软件是免费的。

{"title":"Toward an efficient framework for remote sensing of river bathymetry: Comparing sensors and algorithms on an inaccessible proglacial river in Alaska","authors":"Carl J. Legleiter , Christina M. Leonard , Paul A. Burger , Addison G. Pletcher , Paul J. Kinzel","doi":"10.1016/j.geomorph.2025.110140","DOIUrl":"10.1016/j.geomorph.2025.110140","url":null,"abstract":"<div><div>Remote sensing can provide reliable information on river depths and this approach might be particularly valuable in areas that are difficult to survey via conventional field methods. In this study, we assessed the potential to map the bathymetry of an inaccessible proglacial river in Alaska from both aerial orthophotos and a multispectral satellite image. In addition, we evaluated a variety of depth retrieval algorithms with different input data requirements, including some methods that require field measurements of water depth for calibration and other techniques that can be applied even when such field data are not available. These approaches might enable more efficient use of remote sensing methods by resource management agencies. Our results suggest that bathymetric mapping along the turquoise-colored river we examined was not only feasible but highly accurate (<span><math><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span> up to 0.94) for both types of image data. Algorithms that use paired observations of depth and reflectance to train depth retrieval models were the most accurate, with errors on the order of 15%–20% and little or no bias. Alternative techniques based on hydraulic and statistical concepts also led to strong agreement between predicted and observed depths but were more susceptible to systematic biases toward under- or over-estimation of depth. In contrast to clear-flowing streams, bathymetric mapping in this environment was enabled by a direct relationship between the depth and brightness of the water due to scattering by suspended sediment. In selecting an appropriate depth retrieval method, a compromise might need to be reached between the level of field effort invested and the accuracy of the resulting image-derived bathymetry. Standalone software for implementing these techniques is freely available.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"495 ","pages":"Article 110140"},"PeriodicalIF":3.1,"publicationDate":"2025-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145840679","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}

引用次数: 0