Journal of Glaciology最新文献_第9页

A method to estimate surface mass-balance in glacier accumulation areas based on digital elevation models and submergence velocities 基于数字高程模型和淹没速度估算冰川堆积区地表物质平衡的方法

IF 3.4 3区地球科学

Journal of Glaciology Pub Date : 2023-06-30 DOI: 10.1017/jog.2023.29

B. Jourdain, C. Vincent, M. Réveillet, A. Rabatel, F. Brun, D. Six, Olivier Laarman, L. Piard, P. Ginot, Olivier Sanchez, E. Berthier

{"title":"A method to estimate surface mass-balance in glacier accumulation areas based on digital elevation models and submergence velocities","authors":"B. Jourdain, C. Vincent, M. Réveillet, A. Rabatel, F. Brun, D. Six, Olivier Laarman, L. Piard, P. Ginot, Olivier Sanchez, E. Berthier","doi":"10.1017/jog.2023.29","DOIUrl":"https://doi.org/10.1017/jog.2023.29","url":null,"abstract":"\u0000 Measuring surface mass-balance in the accumulation areas of glaciers is challenging because of the high spatial variability of snow accumulation and the difficulty of conducting annual field glaciological measurements. Here, we propose a method that can solve both these problems for many locations. Ground-penetrating radar measurements and firn cores extracted from a site in the French Alps were first used to reconstruct the topography of a buried end-of-summer snow horizon from a past year. Using these data and surface elevation observations from LiDAR and Global Navigation Satellite System instruments, we calculated the submergence velocities over the period between the buried horizon and more recent surface elevation observations. The differences between the changes in surface elevation and the submergence velocities were then used to calculate the annual surface mass-balances with an accuracy of ±0.34 m w.e. Assuming that the submergence velocities remain stable over several years, the surface mass-balance can be reconstructed for subsequent years from the differences in surface elevation alone. As opposed to the glaciological method that requires substantial fieldwork year after year to provide only point observations, this method, once submergence velocities have been calculated, requires only remote-sensing data to provide spatially distributed annual mass-balances in accumulation areas.","PeriodicalId":15981,"journal":{"name":"Journal of Glaciology","volume":" ","pages":""},"PeriodicalIF":3.4,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42741456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

Bathymetry and bed conditions of Lago Subglacial CECs, West Antarctica 南极洲西部Lago冰下CECs的水深和海床条件

IF 3.4 3区地球科学

Journal of Glaciology Pub Date : 2023-06-29 DOI: 10.1017/jog.2023.38

A. Brisbourne, A. Smith, A. Rivera, R. Zamora, F. Napoleoni, J. Uribe, M. Ortega

{"title":"Bathymetry and bed conditions of Lago Subglacial CECs, West Antarctica","authors":"A. Brisbourne, A. Smith, A. Rivera, R. Zamora, F. Napoleoni, J. Uribe, M. Ortega","doi":"10.1017/jog.2023.38","DOIUrl":"https://doi.org/10.1017/jog.2023.38","url":null,"abstract":"\u0000 Although over 600 Antarctic subglacial lakes have been identified using radar and satellite observations, the bathymetry and bed properties, which are key to understanding conditions within the lake, have been determined in very few localities. We present measurements of water column thickness and lakebed properties from Lago Subglacial CECs (SLC), located beneath 2653 m of ice at the Rutford-Institute-Minnesota divide in Antarctica. Seismic profiles indicate a maximum water column thickness of 301.3 ± 1.5 m, at the widest part of the lake, with an estimated lake volume of 2.5 ± 0.3 km3. Seismic imaging and measurements of the reflection strength at the ice base and lakebed indicate >15 m of high-porosity fine-grained sediment in the central section of the lakebed, consistent with a depositional sequence with an age of up to 0.5 Ma. These observations, along with previous radar measurements and modelling, indicate a low-energy sedimentary environment with a long water-residence time. As such, SLC is a suitable target for exploration via direct access to recover sediment records of ice sheet and climate history and investigate microbial life with long periods of isolation.","PeriodicalId":15981,"journal":{"name":"Journal of Glaciology","volume":" ","pages":""},"PeriodicalIF":3.4,"publicationDate":"2023-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46473033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

Global clustering of recent glacier surges from radar backscatter data, 2017–2022 2017-2022年雷达后向散射数据对近期冰川涌动的全球聚类分析

IF 3.4 3区地球科学

Journal of Glaciology Pub Date : 2023-06-29 DOI: 10.1017/jog.2023.35

A. Kääb, V. Bazilova, P. Leclercq, E. Mannerfelt, T. Strozzi

引用次数: 1

Influence of seasonally varying sea-ice concentration and subsurface ocean heat on sea-ice thickness and sea-ice seasonality for a ‘warm-shelf’ region in Antarctica 季节性变化的海冰浓度和海底热对南极洲“暖架”地区海冰厚度和海冰季节性的影响

IF 3.4 3区地球科学

Journal of Glaciology Pub Date : 2023-06-29 DOI: 10.1017/jog.2023.36

B. Saenz, D. McKee, S. Doney, D. Martinson, S. Stammerjohn

{"title":"Influence of seasonally varying sea-ice concentration and subsurface ocean heat on sea-ice thickness and sea-ice seasonality for a ‘warm-shelf’ region in Antarctica","authors":"B. Saenz, D. McKee, S. Doney, D. Martinson, S. Stammerjohn","doi":"10.1017/jog.2023.36","DOIUrl":"https://doi.org/10.1017/jog.2023.36","url":null,"abstract":"\u0000 Processes driving changes in sea-ice seasonality and sea-ice thickness were explored for a ‘warm-shelf’ region along the West Antarctic Peninsula using vertically coupled sea-ice-ocean thermodynamic simulations, with and without assimilated satellite sea-ice observations and moored ocean temperature observations. Simulations with assimilated sea-ice observations permitted investigation of surface [thermodynamic and dynamic (e.g., wind-driven)] processes affecting sea-ice thickness and seasonality. Assimilation of quasi-weekly variability in the depth and temperature of the deep warm pycnocline permitted examination of subsurface processes affecting sea-ice. Simulations using assimilated sea-ice observations (and implied motion) always produced greater surface heat fluxes and overall thinner sea ice. Assimilating seasonal and quasi-weekly variability in the depth and temperature of the pycnocline modified the start of the sea-ice season by −23 to +1 d, and also modified the sea ice thickness/seasonality to be thinner/shorter or thicker/longer at sub-seasonal and seasonal timescales, highlighting a mechanism where a shoaling pycnocline enhanced upward deep-water heat fluxes as transient surface-induced turbulence had a greater effect on a reduced mixed layer volume. The observed interplay of surface, subsurface, and sea-ice modulation of ocean-atmosphere heat transfer underscores the importance of representing the interaction between sea-ice concentration and upper ocean variability in climate projections.","PeriodicalId":15981,"journal":{"name":"Journal of Glaciology","volume":" ","pages":""},"PeriodicalIF":3.4,"publicationDate":"2023-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41329454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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: 1

Subglacial hydrology modeling predicts high winter water pressure and spatially variable transmissivity at Helheim Glacier, Greenland 冰下水文模型预测格陵兰赫尔海姆冰川冬季高压和空间可变透射率

IF 3.4 3区地球科学

Journal of Glaciology Pub Date : 2023-06-21 DOI: 10.1017/jog.2023.39

A. Sommers, C. Meyer, M. Morlighem, H. Rajaram, K. Poinar, W. Chu, J. Mejia

{"title":"Subglacial hydrology modeling predicts high winter water pressure and spatially variable transmissivity at Helheim Glacier, Greenland","authors":"A. Sommers, C. Meyer, M. Morlighem, H. Rajaram, K. Poinar, W. Chu, J. Mejia","doi":"10.1017/jog.2023.39","DOIUrl":"https://doi.org/10.1017/jog.2023.39","url":null,"abstract":"\u0000 Water pressure beneath glaciers influences ice velocity. Subglacial hydrology models are helpful for gaining insight into basal conditions, but models depend on unconstrained parameters, and a current challenge is reproducing elevated water pressures in winter. We eliminate terms related to englacial storage, opening by sliding, and melt due to changes in the pressure-melting-point temperature, to create a minimalist version of the Subglacial Hydrology And Kinetic, Transient Interactions (SHAKTI) model, and apply this model to Helheim Glacier in east Greenland to explore the winter base state of the subglacial drainage system. Our results suggest that meltwater produced at the bed alone supports active winter drainage with large areas of elevated water pressure and preferential drainage pathways, using a continuum approach that allows for transitions between flow regimes. Transmissivity varies spatially over several orders of magnitude from 10−4 to 103 m2s−1, with regions of weak transmissivity representing poorly connected regions of the system. Bed topography controls the location of primary drainage pathways, and high basal melt rates occur along the steep valley walls. Frictional heat from sliding is a dominant source of basal melt; different approaches for calculating basal shear stress produce significantly different basal melt rates and subglacial discharge.","PeriodicalId":15981,"journal":{"name":"Journal of Glaciology","volume":" ","pages":""},"PeriodicalIF":3.4,"publicationDate":"2023-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48960508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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: 3

‘Stable’ and ‘unstable’ are not useful descriptions of marine ice sheets in the Earth's climate system “稳定”和“不稳定”不是对地球气候系统中海洋冰盖的有用描述

IF 3.4 3区地球科学

Journal of Glaciology Pub Date : 2023-06-21 DOI: 10.1017/jog.2023.40

O. Sergienko, M. Haseloff

{"title":"‘Stable’ and ‘unstable’ are not useful descriptions of marine ice sheets in the Earth's climate system","authors":"O. Sergienko, M. Haseloff","doi":"10.1017/jog.2023.40","DOIUrl":"https://doi.org/10.1017/jog.2023.40","url":null,"abstract":"Investigations of the time-dependent behavior of marine ice sheets and their sensitivity to basal conditions require numerical models because existing theoretical analyses focus only on steady-state configurations primarily with a power-law basal shear stress. Numerical results indicate that the choice of the sliding law strongly affects ice-sheet dynamic behavior. Although observed or simulated grounding-line retreat is typically interpreted as an indication of marine ice sheet instability introduced by Weertman (1974), this (in)stability is a characteristic of the ice sheet's steady states – not time-variant behavior. To bridge the gap between theoretical and numerical results, we develop a framework to investigate grounding line dynamics with generalized basal and lateral stresses (i.e. the functional dependencies are not specified). Motivated by observations of internal variability of the Southern Ocean conditions we explore the grounding-line response to stochastic variability. We find that adding stochastic variability to submarine melt rates that produced stable steady-state configurations leads to intermittently advancing and retreating grounding lines. They can also retreat in an unstoppable manner on time-scales significantly longer than the stochastic correlation time-scales. These results suggest that at any given time of their evolution, the transient behavior of marine ice sheets cannot be described in terms of ‘stable’ or ‘unstable’.","PeriodicalId":15981,"journal":{"name":"Journal of Glaciology","volume":" ","pages":""},"PeriodicalIF":3.4,"publicationDate":"2023-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46945945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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: 2

Water blister geomorphology and subglacial drainage sediments: an example from the bed of the Fennoscandian Ice Sheet in SW Finland 水疱地貌和冰下排水沉积物:芬兰西南部芬诺斯坎德冰盖床的一个例子

3区地球科学

Journal of Glaciology Pub Date : 2023-06-21 DOI: 10.1017/jog.2023.37

Joni Mäkinen, Christine F. Dow, Elina Ahokangas, Antti Ojala, Kari Kajuutti, Juulia Kautto, Jukka-Pekka Palmu

{"title":"Water blister geomorphology and subglacial drainage sediments: an example from the bed of the Fennoscandian Ice Sheet in SW Finland","authors":"Joni Mäkinen, Christine F. Dow, Elina Ahokangas, Antti Ojala, Kari Kajuutti, Juulia Kautto, Jukka-Pekka Palmu","doi":"10.1017/jog.2023.37","DOIUrl":"https://doi.org/10.1017/jog.2023.37","url":null,"abstract":"Abstract This study presents the first light detection and ranging (LiDAR)-based morphometric description of a water blister from a past ice-sheet bed caused by rapid supraglacial drainage. The blister formed during the rapid early Holocene deglaciation of the Fennoscandian Ice Sheet (FIS). It is located in southwest Finland within a subglacial meltwater route interpreted to represent the transition from a distributed to a channelized drainage system. A LiDAR digital elevation model was supplemented with sedimentological and ground-penetrating radar data on blister outflow channels and sedimentology of downflow polymorphous mounds and ridges (PMRs). Unlike the water blisters recorded from the rapid drainage of supraglacial lakes on the Greenland Ice Sheet, the smaller blister size here was either due to crevasse or moulin drainage, or was a supraglacial lake drainage that tapped into a pre-existing, relatively efficient drainage system and related semi-sorted sediments, promoting rapid drainage and reworking of PMRs along the meltwater route. The preservation potential or exposure probability of blister marks is presumably low but they can provide important information about evolution of subglacial drainage systems that is of value to modern interpretations of glacial hydrology.","PeriodicalId":15981,"journal":{"name":"Journal of Glaciology","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135045645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

Post-Little Ice Age glacial lake evolution in Svalbard: inventory of lake changes and lake types 斯瓦尔巴小冰期后冰川湖的演变：湖泊变化和湖泊类型清单

IF 3.4 3区地球科学

Journal of Glaciology Pub Date : 2023-06-14 DOI: 10.1017/jog.2023.34

Iwona Wieczorek, M. Strzelecki, Ł. Stachnik, J. Yde, Jakub Małecki

{"title":"Post-Little Ice Age glacial lake evolution in Svalbard: inventory of lake changes and lake types","authors":"Iwona Wieczorek, M. Strzelecki, Ł. Stachnik, J. Yde, Jakub Małecki","doi":"10.1017/jog.2023.34","DOIUrl":"https://doi.org/10.1017/jog.2023.34","url":null,"abstract":"\u0000 The rapid formation of glacial lakes is one of the most conspicuous landscape changes caused by atmospheric warming in glacierised regions. However, relatively little is known about the history and current state of glacial lakes in the High Arctic. This study aims to address this issue by providing the first inventory of glacial lakes in Svalbard, focusing in particular on the post-Little Ice Age evolution of glacial lakes and their typology. To do so, we used aerial photographs and satellite imagery together with archival topographic data from 1936 to 2020. The inventory comprises the development of 566 glacial lakes (146 km2) that were still in direct contact with glaciers during the period 2008–2012. The results show a consistent increase in the total area of glacial lakes from the 1930s to 2020 and suggest an apparent link between climatic and geological factors, and the formation of specific lake dam types: moraine, ice, or bedrock. We also detected 134 glacial lake drainage events that have occurred since the 1930s. This study shows that Svalbard has one of the highest rates of glacial lake development in the world, which is an indicator of the overall dynamics of landscape change in the archipelago in response to climate change.","PeriodicalId":15981,"journal":{"name":"Journal of Glaciology","volume":" ","pages":""},"PeriodicalIF":3.4,"publicationDate":"2023-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42194197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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: 1

Strong impact of sub-shelf melt parameterisation on ice-sheet retreat in idealised and realistic Antarctic topography 理想和现实南极地形中亚陆架融化参数化对冰盖退缩的强烈影响

IF 3.4 3区地球科学

Journal of Glaciology Pub Date : 2023-06-01 DOI: 10.1017/jog.2023.33

Constantijn J. Berends, L. Stap, R. V. D. van de Wal

{"title":"Strong impact of sub-shelf melt parameterisation on ice-sheet retreat in idealised and realistic Antarctic topography","authors":"Constantijn J. Berends, L. Stap, R. V. D. van de Wal","doi":"10.1017/jog.2023.33","DOIUrl":"https://doi.org/10.1017/jog.2023.33","url":null,"abstract":"\u0000 Future projections of sea-level rise under strong warming scenarios are dominated by mass loss in the marine-grounded sectors of West Antarctica, where thinning shelves as a result of warming oceans can lead to reduced buttressing. This consequently leads to accelerated flow from the upstream grounded ice. However, the relation between warming oceans and increased melt rates under the shelves is very uncertain, especially when interactions with the changing shelf geometry are considered. Here, we compare six widely used, highly parameterised formulations relating sub-shelf melt to thermal forcing. We implemented them in an ice-sheet model, and applied the resulting set-up to an idealised-geometry setting, as well as to the Antarctic ice sheet. In our simulations, the differences in modelled ice-sheet evolution resulting from the choice of parameterisation, as well as the choice of numerical scheme used to apply sub-shelf melt near the grounding line, generally are larger than differences from ice-dynamical processes such as basal sliding, as well as uncertainties from the forcing scenario of the model providing the ocean forcing. This holds for the idealised-geometry experiments as well as for the experiments using a realistic Antarctic topography.","PeriodicalId":15981,"journal":{"name":"Journal of Glaciology","volume":" ","pages":""},"PeriodicalIF":3.4,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43744245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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: 1

Detection of crevassed areas with minimum geometric information: Vernagtferner case study 用最小几何信息检测交叉区域:Vernagtferner案例研究

IF 3.4 3区地球科学

Journal of Glaciology Pub Date : 2023-05-29 DOI: 10.1017/jog.2023.12

Theresa Dobler, W. Hagg, C. Mayer

引用次数: 0