Journal of Glaciology最新文献_第6页

Controls on calving at a large Greenland tidewater glacier: stress regime, self-organised criticality and the crevasse-depth calving law 格陵兰大潮汐冰川崩解的控制:应力状态、自组织临界和裂缝深度崩解规律

IF 3.4 3区地球科学

Journal of Glaciology Pub Date : 2023-12-05 DOI: 10.1017/jog.2023.81

Douglas I. Benn, Joe Todd, Adrian Luckman, Suzanne Bevan, Thomas R. Chudley, Jan Åström, Thomas Zwinger, Samuel Cook, Poul Christoffersen

{"title":"Controls on calving at a large Greenland tidewater glacier: stress regime, self-organised criticality and the crevasse-depth calving law","authors":"Douglas I. Benn, Joe Todd, Adrian Luckman, Suzanne Bevan, Thomas R. Chudley, Jan Åström, Thomas Zwinger, Samuel Cook, Poul Christoffersen","doi":"10.1017/jog.2023.81","DOIUrl":"https://doi.org/10.1017/jog.2023.81","url":null,"abstract":"We investigate the physical basis of the crevasse-depth (CD) calving law by analysing relationships between glaciological stresses and calving behaviour at Sermeq Kujalleq (Store Glacier), Greenland. Our observations and model simulations show that the glacier has a stable position defined by a compressive arch between lateral pinning points. Ice advance beyond the arch results in calving back to the stable position; conversely, if melt-undercutting forces the ice front behind the stable position, it readvances because ice velocities exceed subaqueous melt rates. This behaviour is typical of self-organising criticality, in which the stable ice-front position acts as an attractor between unstable super-critical and sub-critical regimes. This perspective provides strong support for a ‘position-law’ approach to modelling calving at Sermeq Kujalleq, because any calving ‘rate’ is simply a by-product of how quickly ice is delivered to the critical point. The CD calving law predicts ice-front position from the penetration of surface and basal crevasse fields, and accurately simulates super-critical calving back to the compressive arch and melt-driven calving into the sub-critical zone. The CD calving law reflects the glaciological controls on calving at Sermeq Kujalleq and exhibits considerable skill in simulating its mean position and seasonal fluctuations.","PeriodicalId":15981,"journal":{"name":"Journal of Glaciology","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2023-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138508996","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

The relationship between the permeability and liquid water content of polycrystalline temperate ice 多晶温带冰渗透率与液态水含量的关系

IF 3.4 3区地球科学

Journal of Glaciology Pub Date : 2023-12-04 DOI: 10.1017/jog.2023.91

Jacob R. Fowler, Neal R. Iverson

{"title":"The relationship between the permeability and liquid water content of polycrystalline temperate ice","authors":"Jacob R. Fowler, Neal R. Iverson","doi":"10.1017/jog.2023.91","DOIUrl":"https://doi.org/10.1017/jog.2023.91","url":null,"abstract":"To better constrain meltwater transport and ice viscosity in temperate glaciers, particularly in ice stream shear margins, we use a custom permeameter to study the untested model relationship between the permeability of temperate ice and its liquid water content. The permeability of lab-made ice of two mean grain diameters (1.8 and 4.2 mm) is measured, and water content is controlled with the ice salinity and measured calorimetrically. Fluorescein dye is added to through-flowing, chilled water to highlight flow pathways through the ice after experiments. As predicted by a simple model, permeability increases with approximately the square of the water content and by about three orders of magnitude across water contents of 0.1–4.4%. However, permeability values are less than those of the model by average factors of 2.6 and 4.1 for the finer and coarser ice, respectively. This discrepancy is likely due to tortuous, truncated or air-clogged veins. The order-of-magnitude agreement between measured and modeled values may indicate that reduced permeability from these factors is nearly compensated by preferential flow in oversized veins that are isolated or arborescent. Both kinds of preferred flow pathways are observed but the latter only in fine-grained ice at water contents > 2%.","PeriodicalId":15981,"journal":{"name":"Journal of Glaciology","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138508971","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

Observing glacier dynamics with low-cost, multi-GNSS positioning in Victoria Land, Antarctica 在南极洲维多利亚地利用低成本多全球导航卫星系统定位观测冰川动态

IF 3.4 3区地球科学

Journal of Glaciology Pub Date : 2023-11-30 DOI: 10.1017/jog.2023.101

Holly Still, R. Odolinski, M. H. Bowman, Christina Hulbe, David J. Prior

引用次数: 0

Exceptional thinning through the entire altitudinal range of Mont-Blanc glaciers during the 2021/22 mass balance year 在 2021/22 质量平衡年期间，整个勃朗峰冰川高度范围内的冰川异常稀薄

IF 3.4 3区地球科学

Journal of Glaciology Pub Date : 2023-11-29 DOI: 10.1017/jog.2023.100

Etienne Berthier, Christian Vincent, Delphine Six

引用次数: 0

Modelled frontal ablation and velocities at Kronebreen, Svalbard, are sensitive to the choice of submarine melt rate scenario 模拟的斯瓦尔巴群岛克罗内布林的锋面消融和速度对海底融化速率情景的选择很敏感

IF 3.4 3区地球科学

Journal of Glaciology Pub Date : 2023-11-29 DOI: 10.1017/jog.2023.94

Felicity Alice Holmes, Eef van Dongen, Nina Kirchner

引用次数: 0

Capturing the transition from marine to land-terminating glacier from the 126-year retreat history of Nordenskiöldbreen, Svalbard 从斯瓦尔巴群岛Nordenskiöldbreen 126年的退缩历史中捕捉到从海洋到陆地的冰川转变

IF 3.4 3区地球科学

Journal of Glaciology Pub Date : 2023-11-24 DOI: 10.1017/jog.2023.92

Jan Kavan, Petra Luláková, Jakub Małecki, Mateusz Czesław Strzelecki

引用次数: 0

Semantic segmentation of glaciological features across multiple remote sensing platforms with the Segment Anything Model (SAM) 基于分段任意模型(SAM)的多遥感平台冰川特征语义分割

IF 3.4 3区地球科学

Journal of Glaciology Pub Date : 2023-11-24 DOI: 10.1017/jog.2023.95

Siddharth Shankar, Leigh A. Stearns, C. J. van der Veen

{"title":"Semantic segmentation of glaciological features across multiple remote sensing platforms with the Segment Anything Model (SAM)","authors":"Siddharth Shankar, Leigh A. Stearns, C. J. van der Veen","doi":"10.1017/jog.2023.95","DOIUrl":"https://doi.org/10.1017/jog.2023.95","url":null,"abstract":"Semantic segmentation is a critical part of observation-driven research in glaciology. Using remote sensing to quantify how features change (e.g. glacier termini, supraglacial lakes, icebergs, crevasses) is particularly important in polar regions, where glaciological features may be spatially small but reflect important shifts in boundary conditions. In this study, we assess the utility of the Segment Anything Model (SAM), released by Meta AI Research, for cryosphere research. SAM is a foundational AI model that generates segmentation masks without additional training data. This is highly beneficial in polar science because pre-existing training data rarely exist. Widely-used conventional deep learning models such as UNet require tens of thousands of training labels to perform effectively. We show that the Segment Anything Model performs well for different features (icebergs, glacier termini, supra-glacial lakes, crevasses), in different environmental settings (open water, mélange, and sea ice), with different sensors (Sentinel-1, Sentinel-2, Planet, timelapse photographs) and different spatial resolutions. Due to the performance, versatility, and cross-platform adaptability of SAM, we conclude that it is a powerful and robust model for cryosphere research.","PeriodicalId":15981,"journal":{"name":"Journal of Glaciology","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2023-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138508972","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

Development of a drone-based ground-penetrating radar system for efficient and safe 3D and 4D surveying of alpine glaciers 基于无人机的高寒冰川三维和四维高效安全探地雷达系统的研制

IF 3.4 3区地球科学

Journal of Glaciology Pub Date : 2023-11-23 DOI: 10.1017/jog.2023.83

Bastien Ruols, Ludovic Baron, James Irving

{"title":"Development of a drone-based ground-penetrating radar system for efficient and safe 3D and 4D surveying of alpine glaciers","authors":"Bastien Ruols, Ludovic Baron, James Irving","doi":"10.1017/jog.2023.83","DOIUrl":"https://doi.org/10.1017/jog.2023.83","url":null,"abstract":"Recent research has highlighted the potential for high-resolution, high-density, 3D and 4D ground-penetrating radar (GPR) acquisitions on alpine glaciers. When carried out on foot, such surveys are laborious and time consuming, which limits their application to small domains of limited glaciological interest. Further, crevasses and other hazards make the data acquisition risky. To address these issues, we have developed a drone-based GPR system. The system has a payload weight of 2.2 kg and a data output rate of 14 traces per second. An 80-MHz antenna and a recording time of 2800 ns mean that depths of over 100 m can be reached in temperate ice. Differential GPS positioning assures accurate flight paths. At a speed of 4 m s−1 and height of 5 m above the glacier surface, our system can acquire over 4 line-km of GPR data in 20 min on a single set of drone batteries. After presenting the technical specifications of the system and tests required to optimize its performance, we showcase a recently acquired 3D dataset from the Otemma glacier in Switzerland, where 462 parallel GPR profiles were surveyed at a 1-m line spacing, totaling over 112 line-km of data, in only 4 days.","PeriodicalId":15981,"journal":{"name":"Journal of Glaciology","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2023-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138508974","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

Surface mass balance and energy balance of the 79N Glacier (Nioghalvfjerdsfjorden, NE Greenland) modeled by linking COSIPY and Polar WRF – CORRIGENDUM 通过连接 COSIPY 和极地 WRF 模拟 79N 冰川（格陵兰东北部 Nioghalvfjerdsfjorden）的地表质量平衡和能量平衡 - CORRIGENDUM

IF 3.4 3区地球科学

Journal of Glaciology Pub Date : 2023-11-17 DOI: 10.1017/jog.2023.96

M. T. Blau, J. V. Turton, T. Sauter, T. Mölg

引用次数: 0

Ice geometry and thermal regime of Lyngmarksbræen Ice Cap, West Greenland 西格陵兰Lyngmarksbræen冰帽的冰的几何形状和热状态

3区地球科学

Journal of Glaciology Pub Date : 2023-11-10 DOI: 10.1017/jog.2023.89

Mette Kusk Gillespie, Jacob Clement Yde, Marit Svarstad Andresen, Michele Citterio, Mark Andrew Kusk Gillespie

{"title":"Ice geometry and thermal regime of Lyngmarksbræen Ice Cap, West Greenland","authors":"Mette Kusk Gillespie, Jacob Clement Yde, Marit Svarstad Andresen, Michele Citterio, Mark Andrew Kusk Gillespie","doi":"10.1017/jog.2023.89","DOIUrl":"https://doi.org/10.1017/jog.2023.89","url":null,"abstract":"Abstract Observations remain sparse for peripheral glaciers and ice caps in Greenland. Here, we present the results of a multi-frequency radar survey of Lyngmarksbræen Ice Cap in West Greenland conducted in April 2017. Radar measurements show thick ice of up to ~120 m in subglacial valleys associated with the largest outlet glaciers, while relatively thin ice cover the upper plateau ice divides, suggesting future vulnerability to ice cap fragmentation. At the time of the radar survey, Lyngmarksbræen Ice Cap had a total volume of 0.82 ± 0.1 km 3 . Measurements show a 1.5–2 m thick end-of-winter snowpack, and that firn is largely absent, signifying a prolonged period of negative mass balance for most of the ice cap. The thermal regime of Lyngmarksbræen Ice Cap is investigated through analysis of scattering observed along radar profiles. Results show that the ice cap is largely below the pressure melting point, but that temperate ice exists both in deep basal pockets and in shallow zones that some places extend from ~15 m depth and to the ice base. The distribution of shallow temperate ice appears unrelated to variations in ice thickness; instead we find a strong correlation to the presence of nearby surface crevasses.","PeriodicalId":15981,"journal":{"name":"Journal of Glaciology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135091707","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