Geomorphology最新文献

{"title":"Seasonal vertical accretion in different hydro-geomorphic environments of Indian Sundarban: Assessing the role of mangroves in mitigating sea level rise impacts","authors":"","doi":"10.1016/j.geomorph.2024.109493","DOIUrl":"10.1016/j.geomorph.2024.109493","url":null,"abstract":"<div><div>The Indian Sundarban, renowned for its unique hydro-geomorphic diversity, faces rising threats from sea level rise, necessitating an examination of the spatio-temporal variation of vertical accretion and the role played by mangroves in mitigating these impacts. As such, fifteen transects were chosen across buffer and transition zones of Indian Sundarban, each equipped with 4–6 sedimentation pins, to gauge accretion rates in premonsoon, monsoon, and postmonsoon season during period March 2020 to March 2022, considering diverse hydro-geomorphic attributes. The vertical accretion rate exhibits a curvilinear pattern, ascending from the lower seafront zone towards the middle of the estuarine region, reaching a peak, and subsequently declining towards the upper estuarine zones. Specifically, in the seafront zone, the yearly mean accretion (focusing solely on accretion and excluding subsidence) ranges between 5 and 10 mm/year, while in the middle estuarine region, it increases to an average of 38.1 ± 9.44 mm/year. However, in the upper zone, the yearly mean accretion decreases slightly to approximately 17.71 ± 9.54 mm/year. Similar patterns are observed when considering the distance from the riverfront to the interior of the mangrove zones. Seasonal analysis demonstrates that the postmonsoon period exhibits the highest accretion, followed by the premonsoon season, while the monsoon tends to be erosional in nature. Mangrove zonation, and subsequent distribution of root height, root diameter, root density, tree density, tree basal area, inundation frequency, current speed, variation in suspended sediment concentration were identified as influential factors affecting vertical accretion rates. Based on multiple regression analysis, root density, inundation frequency, and tree density demonstrated moderate-positive correlations with vertical accretion, whereas distance from the riverfront, root height, and root diameter displayed negative correlations. This study enhances our understanding of the intricate processes behind vertical accretion in the Sundarban, offering valuable insights for future research and advancing discussions on the broader implications of climate change in coastal regions.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142578636","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":"Automatic extraction of Transverse Aeolian Ridges (TARs) and analysis of landform influence for the Zhurong landing area on Mars","authors":"","doi":"10.1016/j.geomorph.2024.109489","DOIUrl":"10.1016/j.geomorph.2024.109489","url":null,"abstract":"<div><div>The morphology and surface characteristics of Transverse Aeolian Ridges (TARs) reflect the recent and current environmental evolution of Mars. This study investigates the influence of typical Martian non-aeolian landforms impacted on the distribution and morphology of TARs using multi-source high-resolution orbiter images in the Zhurong rover's landing region at the south of Utopian Plain. This study proposes an automatic and effective approach for extracting TARs, while classifying their types and estimating their geometric parameters, including length, width, height, and angle. The obtained results confirm the effectiveness of the proposed method. In the Zhurong rover's landing region, TARs in flat areas have a sparse distribution and simple morphology. However, TARs are more concentrated and diverse in morphology around typical non-aeolian landforms such as cones and troughs. The orientation of TARs is determined by wind direction, and their width is affected by sediment richness. The morphology and distribution of TARs are also influenced by typical non-aeolian landforms, which modify local wind fields and sediments.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142578735","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":"Unveiling gully erosion susceptibility: A semi-quantitative modeling approach integrated with field data in contrasting landscapes and climate regions","authors":"","doi":"10.1016/j.geomorph.2024.109485","DOIUrl":"10.1016/j.geomorph.2024.109485","url":null,"abstract":"<div><div>This study addresses the challenge of mapping gully erosion susceptibility, which is often hindered by limited observed data, the complexity of controlling factors, and the uncertainties associated with characterizing these factors. We utilized a semi-quantitative modeling approach that integrates field-based data and ten controlling factors in the Chemoga watershed of Ethiopia's Upper Blue Nile basin. The resulting gully erosion susceptibility map was compared with a random forest-based approach to assess the methodological applicability. Additionally, an independent dataset from adjacent watersheds was used to validate the approach. The findings revealed that certain landscape positions with specific elevation ranges and slope steepness were more susceptible to gully erosion due to factors such as rainfall, lithological formations, soil characteristics, and agricultural activities. Approximately 10 % of the watershed area was affected by gully erosion, with varying susceptibility levels. The comparison between the semi-quantitative and random forest approaches demonstrates a total agreement of around 58 %, with minimal differences in susceptibility classes. The study also highlights a strong agreement between simulated and observed susceptibility maps, with a 76 % PBIAS (Percent Bias) value for the simulation and a lower 48 % agreement for the random forest approach. Furthermore, in the adjacent watershed, 65 % of the area exhibits no discrepancies between observed and simulated maps. This suggests that the semi-quantitative approach is effective in extrapolating gully erosion susceptibility when detailed data is limited, offering a cost-effective and efficient solution. The study emphasizes the utility of the semi-quantitative modeling approach in mapping gully erosion susceptibility and its potential for practical applications in land management and intervention strategies.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593557","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":"Meteorological factors control debris slides and debris flows in a high-Arctic glacier basin (Ny-Ålesund, Svalbard)","authors":"","doi":"10.1016/j.geomorph.2024.109492","DOIUrl":"10.1016/j.geomorph.2024.109492","url":null,"abstract":"<div><div>Landslide processes are one of the dominant agents of erosion and sediment transport on sediment-mantled slopes in arctic environments. Increased landslide activity is anticipated as climate change is projected to decrease mountain slope stability. High-Arctic environments, such as Svalbard, serve as crucial observatories for investigating current and future slope dynamics within a changing climate, particularly due to arctic amplification effects. Despite the significance of Arctic regions, empirical evidence in high latitudes is often lacking. This scarcity can be attributed to the absence of long-term, high-resolution terrain data with sufficient temporal resolution to assess the impact of meteorological boundary conditions on landscapes altered by climate change. However, addressing this gap in empirical evidence is essential for understanding the complex interplay between meteorological variables and debris slide and debris flow evolution in Arctic environments. This study presents a unique high-resolution remote sensing dataset within a high-Arctic glacier basin acquired over a 10-year period. Through the combination of terrestrial laser-scanning and an autonomous camera network, we were able to investigate the impact of meteorological boundary conditions on the trigger mechanisms of translational debris slides and debris flows and unravel paraglacial slope evolution following recent glacier retreat on the example of the Austre Lovénbreen glacier basin (Svalbard, Norway). Translational debris slides accounted for approximately 96 % (<em>N</em> = 147) of the total sediment flux observed, with debris flows (<em>N</em> = 21) acting as a secondary agent of sediment transport. The debris slide activity significantly increased between 2011 and 2021. Heavy rainfall events primarily influence the frequency and magnitude of debris slides during the hydrological summer, while the duration and intensity of the thawing period serve as the principal control for their initiation. Furthermore, a 2-year recurrence period for major debris flows (≥ 400 m³) was found, which is about 2.5 to 5 times shorter than previous estimates for the last few decades on Svalbard. In conclusion, this study highlights the impact of meteorological factors on debris slide frequency and magnitude within high-Arctic glacier basins, shedding light on the dynamics of paraglacial slope modification in Arctic environments affected by climate change.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593554","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":"Controls on coastal bluff erosion of a drowned drumlin field: Boston Harbor, Massachusetts","authors":"","doi":"10.1016/j.geomorph.2024.109490","DOIUrl":"10.1016/j.geomorph.2024.109490","url":null,"abstract":"<div><div>Eroding coastal bluffs pose significant risks to coastal communities, and an improved understanding of their erosional processes and mechanisms is essential for developing effective management strategies. The Boston Harbor Islands comprise more than two dozen drowned drumlins that were formed during the late-Pleistocene, many of which are now connected by spits. Exposed bluffs on the islands experience erosion due to waves and precipitation and are increasingly threatened by accelerating sea-level rise (SLR). Retreat rates for 31 bluffs along the drumlin shore, derived from orthoimagery (1995–2021) using the Digital Shoreline Analysis System add-in for ArcMap 10.8, range from 0.0 m/yr to 1.5 m/yr. These rates were examined in relation to several factors, including shoreline orientation, significant wave height during extratropical storms, till matrix composition, base elevation, bluff height, and presence of engineering structures. Clusters of bluffs with similar characteristics were identified, suggesting that high retreat rates coincide with bluffs that experience high wave energy, face the northeast and have high sand-to-mud ratios. The complexity of the Boston Harbor drumlin field and the variability of individual factors controlling erosion highlights the impracticality of developing a universal statistical model for predicting erosion rates. Rather a more suitable approach involves assessing trends among clusters of bluffs with similar characteristics. A similar approach can be taken for exploring the variability in retreat rates along other coastlines with complex or irregular bluff systems and wave fields.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593636","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":"Scale-dependent interactions in coastal biogeomorphic landscapes: Pioneer both inhibits and facilitates primary foredune builder across spatial scales","authors":"","doi":"10.1016/j.geomorph.2024.109486","DOIUrl":"10.1016/j.geomorph.2024.109486","url":null,"abstract":"<div><div>Ecosystem engineers often drive landscape formation and vegetation succession by modifying environmental conditions. Along the Northwestern European coast, dune formation is classically believed to be pioneered by sand couch (<em>Elytrigia juncea</em>), followed by the primary foredune builder marram grass (<em>Calamagrostis arenaria</em>, formerly <em>Ammophila arenaria</em>) once sufficiently large dunes have formed. However, these ideas lack experimental validation, leaving the specific relationship between sand couch, the landscape they form, and marram grass establishment unknown. Here, we experimentally investigated this relationship by planting 975 young marram grass plants in two sand couch dominated, embryonic dune systems. Using structural equation models, we examined the effect of sand couch and the landscape attributes (i.e., elevation, distance to sea and elevation change) on marram grass establishment. Results reveal indirect local inhibition by sand couch via landscape modifications on survival of establishing marram grass. Specifically, sand couch elevated the environment. In turn, elevated areas eroded (i.e., changed in elevation) more in winter, which was the key factor reducing marram grass survival. At the landscape scale, however, we observed the highest survival in relatively stable and sheltered microsites formed because of sand couch induced dune building. While the indirect local inhibition by sand couch for marram grass survival was found at both locations, the direct effect of sand couch on marram grass survival and shoot formation were location and thus context dependent. For marram grass survival, the relation with sand couch was neutral in exposed and positive in sheltered conditions and for shoot formation it was negative in exposed and neutral in sheltered conditions. Similar to scale-dependent interactions found in other biogeomorphic landscapes (e.g., salt marshes, seagrass, mussel beds), we suggest that interspecific facilitation acts on larger spatial scales rather than the commonly suggested small-scale facilitation through created elevation. More specifically, we suggest that dune formation by pioneer species leads to the creation of stable and sheltered microsites beneficial for establishment of later successional species at the landscape-scale.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142578637","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":"Morphometric characteristics of glacial cirques and former glaciers in the Geyik Mountains, Western Taurus, Türkiye","authors":"","doi":"10.1016/j.geomorph.2024.109474","DOIUrl":"10.1016/j.geomorph.2024.109474","url":null,"abstract":"<div><div>Using the Glacier reconstruction (GlaRe) toolbox, reconstructions of former glaciers in the Geyik Mountains, part of the Taurus Mountain system in southern Türkiye, show that an area of 132.5 km² was glaciated in the last major glaciation, which left clear terminal and hummocky moraines. Glaciers were 1.4 to 12 km long and those from 49 cirques merged to form a broad 75 km² piedmont glacier in the Namaras Valley, up to 400 m thick. A thorough analysis of morphometry of the 98 Geyik cirques, using the revised Automated Cirque Metric Extraction version 2 (ACME2) toolbox, shows that they are relatively small, with limited widths: the median length/width ratio of 1.29 is unusually high. With size, length and width increase faster than depth, demonstrating strong static allometry. Maximum slope averages 59°, minimum 3.3° and axial 25°. A combination of low hypsometric integral, high axial profile closure and high axial height-length integral is proposed as a measure of cirque development.</div><div>The main summits are on sharp ridges on cirque crests, showing that they have been lowered by glacial erosion (by cirque development). Glaciation was strongly asymmetric, with cirque vector mean aspect between northeast and north-northeast. This shows the dominance of solar radiation effects, with some modification from westerly winds. Glacier palaeo- Equilibrium Line Altitudes (pELAs) rise northeastwards and cirque floor minimum altitudes (CFAs) rise toward east-northeast, both showing the importance of moist air from the Mediterranean, 38–55 km to the southwest. pELA averages 2208 m above sea level (a.s.l.) (2277 m area-weighted); CFA averages 2234 m. CFA varies mainly with summit altitudes; where related palaeoglaciers are short CFA is somewhat below pELA, but for longer ones it is above. The most likely palaeoclimate to form these glaciers involves a precipitation increase of 53–72 % with a temperature fall of 8 °C compared with present-day. The cirques formed under similar or less severe conditions.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142578638","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":"On the effect of two-direction seasonal flows on barchans and the origin of occluded dunes","authors":"","doi":"10.1016/j.geomorph.2024.109488","DOIUrl":"10.1016/j.geomorph.2024.109488","url":null,"abstract":"<div><div>We inquire into the morphodynamics of barchans under seasonal flows. For that, we carried out grain-scale numerical computations of a subaqueous barchan exposed to two-directional flows, and we varied the angle and frequency of oscillations. We show that when the frequency is lower than the inverse of the characteristic time for barchan formation, the dune adapts to the new flow direction and recovers the barchan shape while losing less grains than under one-directional flow. For higher frequencies, the dune has not enough time for adaptation and becomes more round while losing more grains. For both cases, we show, for the first time, the typical dynamics of grains (trajectories and forces). In particular, the round barchans are similar to the so-called occluded dunes observed on Mars, where seasons have very high frequencies compared to the dune timescale, different from Earth. Our results represent a possible explanation for that shape.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593555","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":"Inventory of active rock glaciers and their distribution characteristics on the Qinghai-Tibet Plateau and its adjacent mountainous regions","authors":"","doi":"10.1016/j.geomorph.2024.109468","DOIUrl":"10.1016/j.geomorph.2024.109468","url":null,"abstract":"<div><div>With the global climate change, glaciers on the Qinghai-Tibet Plateau (QTP) and its adjacent mountainous regions are retreating rapidly, leading to an increase in active rock glaciers (ARGs) in front of glaciers. As crucial components of water resources in alpine regions and indicators of permafrost boundaries, ARGs reflect climatic and environmental changes on the QTP and its adjacent mountainous regions. However, the extensive scale of rock glacier development poses a challenge to field investigations and sampling, and manual visual interpretation requires substantial effort. Consequently, research on rock glacier cataloging and distribution characteristics across the entire area is scarce. This study statistically analyzed the geometric characteristics of ARGs using high-resolution GF-2 satellite images. It examined their spatial distribution and relationship with local factors. The findings reveal that 34,717 ARGs, covering an area of approximately 6873.54 km², with an average area of 0.19 ± 0.24 km², a maximum of 0.0012 km², and a minimum of 4.6086 km², were identified primarily in north-facing areas at elevations of 4300–5300 m and slopes of 9°–25°, predominantly in the Karakoram Mountains and the Himalayas. Notably, the largest concentration of ARGs was found on north-facing shady slopes, constituting about 42 % of the total amount, due to less solar radiation and lower near-surface temperatures favorable for interstitial ice preservation. This research enriches the foundational data on ARG distribution across the QTP and its adjacent mountainous regions, offering significant insights into the response mechanisms of rock glacier evolution to environmental changes and their environmental and engineering impacts.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142571898","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":"Oceanic geodiversity along back-arc spreading centers reveals analogies with mid-ocean ridges","authors":"","doi":"10.1016/j.geomorph.2024.109466","DOIUrl":"10.1016/j.geomorph.2024.109466","url":null,"abstract":"<div><div>Oceanic geodiversity provides essential information on the dynamics of the Earth. Here, we focus on the geodiversity of three oceanic back-arc spreading centers: the Mariana Spreading Center, the Central-Southern Lau Basin spreading centers, and the East Scotia Ridge. We defined a method to identify their axial zones, obtaining spreading center depths along the basins. Results improve global plate boundary models and morphology variations, revealing that the average depths along the Mariana, East Scotia, and Lau Basin spreading ridges are 4.5, 3.5, and 2 km, respectively. We also measured new spreading rates based on five magnetic profiles crossing the three back-arc spreading centers, contributing to plate kinematic models. Furthermore, we computed subduction rates, including hinge velocities along the Mariana, South Sandwich, and Tonga Subductions, to understand the existing interactions between the subducting slab hinge motion and the kinematics of their related back-arc spreading centers. Our bathymetric, magnetic, and kinematic data show several differences among the Mariana, the East Scotia, and the Lau spreading centers, stressing the oceanic geodiversity in a similar geodynamic context. Our results also suggest a strong correlation between axial depth and full spreading rates along the back-arc spreading centers, a geological correspondence that allows a similar description of these divergent plate boundaries within the mid-ocean ridge classification. Finally, we show how hinge kinematics affects the relationship between convergence along subduction zones and back-arc spreading rates. All our findings contribute to understand how the oceanic geodiversity is directly related to geodynamic processes, increasing the knowledge of global tectonics.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142560773","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}