Journal of Glaciology最新文献

Rift propagation signals the last act of the Thwaites Eastern Ice Shelf despite low basal melt rates 尽管基底融化率较低，但裂谷扩展预示着斯怀兹东部冰架的最后一幕

IF 3.4 3区地球科学

Journal of Glaciology Pub Date : 2024-09-19 DOI: 10.1017/jog.2024.64

Christian T. Wild, Samuel B. Kachuck, Adrian Luckman, Karen E. Alley, Meghan A. Sharp, Haylee Smith, Scott W. Tyler, Christopher Kratt, Tiago S. Dotto, Daniel Price, Keith W. Nicholls, Suzanne L. Bevan, Gabriela Collao-Barrios, Atsuhiro Muto, Martin Truffer, Ted A. Scambos, Karen J. Heywood, Erin C. Pettit, the TARSAN team

{"title":"Rift propagation signals the last act of the Thwaites Eastern Ice Shelf despite low basal melt rates","authors":"Christian T. Wild, Samuel B. Kachuck, Adrian Luckman, Karen E. Alley, Meghan A. Sharp, Haylee Smith, Scott W. Tyler, Christopher Kratt, Tiago S. Dotto, Daniel Price, Keith W. Nicholls, Suzanne L. Bevan, Gabriela Collao-Barrios, Atsuhiro Muto, Martin Truffer, Ted A. Scambos, Karen J. Heywood, Erin C. Pettit, the TARSAN team","doi":"10.1017/jog.2024.64","DOIUrl":"https://doi.org/10.1017/jog.2024.64","url":null,"abstract":"Rift propagation, rather than basal melt, drives the destabilization and disintegration of the Thwaites Eastern Ice Shelf. Since 2016, rifts have episodically advanced throughout the central ice-shelf area, with rapid propagation events occurring during austral spring. The ice shelf's speed has increased by ~70% during this period, transitioning from a rate of 1.65 m d−1 in 2019 to 2.85 m d−1 by early 2023 in the central area. The increase in longitudinal strain rates near the grounding zone has led to full-thickness rifts and melange-filled gaps since 2020. A recent sea-ice break out has accelerated retreat at the western calving front, effectively separating the ice shelf from what remained of its northwestern pinning point. Meanwhile, a distributed set of phase-sensitive radar measurements indicates that the basal melting rate is generally small, likely due to a widespread robust ocean stratification beneath the ice–ocean interface that suppresses basal melt despite the presence of substantial oceanic heat at depth. These observations in combination with damage modeling show that, while ocean forcing is responsible for triggering the current West Antarctic ice retreat, the Thwaites Eastern Ice Shelf is experiencing dynamic feedbacks over decadal timescales that are driving ice-shelf disintegration, now independent of basal melt.","PeriodicalId":15981,"journal":{"name":"Journal of Glaciology","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142262627","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

Retreat of the Greenland Ice Sheet leads to divergent patterns of reconfiguration at its freshwater and tidewater margins 格陵兰冰盖的退缩导致其淡水和潮水边缘出现不同的重组模式

IF 3.4 3区地球科学

Journal of Glaciology Pub Date : 2024-09-16 DOI: 10.1017/jog.2024.61

Jonathan Ryan, Theo Ross, Sarah Cooley, Dominik Fahrner, Nicole Abib, Victoria Benson, David Sutherland

{"title":"Retreat of the Greenland Ice Sheet leads to divergent patterns of reconfiguration at its freshwater and tidewater margins","authors":"Jonathan Ryan, Theo Ross, Sarah Cooley, Dominik Fahrner, Nicole Abib, Victoria Benson, David Sutherland","doi":"10.1017/jog.2024.61","DOIUrl":"https://doi.org/10.1017/jog.2024.61","url":null,"abstract":"Greenland's marine- and land-terminating glaciers are retreating inland due to climate warming, reconfiguring the way the ice sheet interacts with its proglacial environment. Here we use three decades of satellite imagery to determine whether the ice-sheet margin is becoming more or less exposed to marine and lacustrine processes. During our 1990–2019 study period, we find that the length of ice-sheet perimeter in contact with the ocean shrank by 12.3 ± 3.8% (196.2 ± 10.4 km), due to the retreat of marine-terminating glaciers into narrower fjords. On the other hand, we find that the length of the ice-sheet perimeter in contact with freshwater lakes exhibited more divergent trends that is better explored at regional scales. The length of ice–lake boundaries increased in southwest, north and northwest Greenland but declined in southeast and central east Greenland. The magnitude of change we document during our study period leads us to conclude that the ice sheet is poised for further, substantial reconfiguration in the coming decades with consequences for the flux of fresh water, nutrients and primary productivity in Greenland's terrestrial and oceanic environment.","PeriodicalId":15981,"journal":{"name":"Journal of Glaciology","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142262631","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

Implications of high-resolution velocity and strain rate observations for modelling of Greenlandic tidewater glaciers 高分辨率速度和应变率观测对格陵兰潮水冰川建模的影响

IF 3.4 3区地球科学

Journal of Glaciology Pub Date : 2024-09-16 DOI: 10.1017/jog.2024.63

Dominik Fahrner, Pablo J. González, Douglas W. F. Mair, James M. Lea

{"title":"Implications of high-resolution velocity and strain rate observations for modelling of Greenlandic tidewater glaciers","authors":"Dominik Fahrner, Pablo J. González, Douglas W. F. Mair, James M. Lea","doi":"10.1017/jog.2024.63","DOIUrl":"https://doi.org/10.1017/jog.2024.63","url":null,"abstract":"Synthetic Aperture Radar (SAR) has been used extensively to determine the surface ice flow velocity of tidewater glaciers and investigate changes in seasonal or annual ice dynamics at medium spatial resolution (⩾100 m). However, assessing tidewater glacier behaviour at these resolutions risks missing key details of glacier dynamics, which is particularly important for determination of strain rates that relate to crevasse formation, depth, and ice damage. Here we present surface ice velocity and strain maps with a 16 m posting derived from high-resolution (1 m) PAZ Ciencia spotlight mode SAR imagery for Narsap Sermia, SW Greenland, for October 2019 to February 2021. Results reveal fine details in strain rate, including an area of compression proximal to the terminus, with an upstream shift of strains through time. The velocity evolution of Narsap Sermia shows distinct seasonal changes starting in summer 2020, which are largely modulated by the subglacial drainage system. Comparison of our results with medium-resolution velocity products shows that while these can capture general strain and velocity patterns, our high-resolution data reveals considerably larger ranges of strain values. This is likely to have implications for tuning strain rate dependent calving and ice damage parameterisations within numerical models.","PeriodicalId":15981,"journal":{"name":"Journal of Glaciology","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142262628","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

Mechanical properties of pressure-frozen ice under triaxial compressive stress 压力冻结冰在三轴压应力作用下的机械特性

IF 3.4 3区地球科学

Journal of Glaciology Pub Date : 2024-09-16 DOI: 10.1017/jog.2024.59

Peixin Sun, Weihao Yang, Jukka Tuhkuri

{"title":"Mechanical properties of pressure-frozen ice under triaxial compressive stress","authors":"Peixin Sun, Weihao Yang, Jukka Tuhkuri","doi":"10.1017/jog.2024.59","DOIUrl":"https://doi.org/10.1017/jog.2024.59","url":null,"abstract":"Artificial ground freezing is an effective method for underground constructions in deep alluvium. To study the compressive strength of frozen soil under high ground pressure and high hydraulic pressure, it is necessary to understand the mechanical behaviour of ice that is formed under triaxial compressive stress. A low-temperature triaxial test system was developed and used to study both formation and deformation of columnar ice under hydrostatic pressure. Cylindrical ice specimens 125 mm in height and 61.8 mm in diameter were prepared and tested under constant strain rates. At a strain rate of 5 × 10−5 s−1, the peak axial stress showed a linear increase as the confining pressure increased from 2 to 30 MPa, while the peak deviatoric stress exhibited a slight decrease. At a confining pressure of 30 MPa, the peak deviatoric stress showed a logarithmic increase with the strain rate increasing from 5 × 10−6 to 5 × 10−4 s−1, and the failure strain nearly doubled. A power law relationship between the time to failure and the strain rate was also observed. In this study, each test consistently demonstrated a ductile failure mode, with a noticeable reduction in cracking as the confining pressure increased. Due to the effect of the high confining pressure, crack propagation was suppressed, and an apparent recrystallization after peak stress was observed.","PeriodicalId":15981,"journal":{"name":"Journal of Glaciology","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142262630","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

Exploring canyons beneath Devon Ice Cap for sub-glacial drainage using radar and thermodynamic modeling 利用雷达和热力学建模探索德文冰帽下的峡谷冰川下排水系统

IF 3.4 3区地球科学

Journal of Glaciology Pub Date : 2024-09-16 DOI: 10.1017/jog.2024.49

Chris Pierce, Mark Skidmore, Lucas Beem, Don Blankenship, Ed Adams, Christopher Gerekos

{"title":"Exploring canyons beneath Devon Ice Cap for sub-glacial drainage using radar and thermodynamic modeling","authors":"Chris Pierce, Mark Skidmore, Lucas Beem, Don Blankenship, Ed Adams, Christopher Gerekos","doi":"10.1017/jog.2024.49","DOIUrl":"https://doi.org/10.1017/jog.2024.49","url":null,"abstract":"Sub-glacial canyon features up to 580 m deep between flat terraces were identified beneath Devon Ice Cap during a 2023 radar echo sounding (RES) survey. The largest canyon connects a hypothesized brine network near the Devon Ice Cap summit with the marine-terminating Sverdrup outlet glacier. This canyon represents a probable drainage route for the hypothesized water system. Radar bed reflectivity is consistently 30 dB lower along the canyon floor than on the terraces, contradicting the signature expected for sub-glacial water. We compare these data with backscattering simulations to demonstrate that the reflectivity pattern may be topographically induced. Our simulated results indicated a 10 m wide canal-like water feature is unlikely along the canyon floor, but smaller features may be difficult to detect via RES. We calculated basal temperature profiles using a 2D finite difference method and found the floor may be up to 18°C warmer than the terraces. However, temperatures remain below the pressure melting point, and there is limited evidence that the canyon floor supports a connected drainage system between the DIC summit and Sverdrup Glacier. The terrain beneath Devon Ice Cap demonstrates limitations for RES. Future studies should evaluate additional correction methods near complex terrain, such as RES simulation as we demonstrate here.","PeriodicalId":15981,"journal":{"name":"Journal of Glaciology","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142262629","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

DAS to discharge: using distributed acoustic sensing (DAS) to infer glacier runoff 利用分布式声学传感（DAS）推断冰川径流

IF 3.4 3区地球科学

Journal of Glaciology Pub Date : 2024-08-27 DOI: 10.1017/jog.2024.46

John-Morgan Manos, Dominik Gräff, Eileen Rose Martin, Patrick Paitz, Fabian Walter, Andreas Fichtner, Bradley Paul Lipovsky

{"title":"DAS to discharge: using distributed acoustic sensing (DAS) to infer glacier runoff","authors":"John-Morgan Manos, Dominik Gräff, Eileen Rose Martin, Patrick Paitz, Fabian Walter, Andreas Fichtner, Bradley Paul Lipovsky","doi":"10.1017/jog.2024.46","DOIUrl":"https://doi.org/10.1017/jog.2024.46","url":null,"abstract":"Observations of glacier melt and runoff are of fundamental interest in the study of glaciers and their interactions with their environment. Considerable recent interest has developed around distributed acoustic sensing (DAS), a sensing technique which utilizes Rayleigh backscatter in fiber optic cables to measure the seismo-acoustic wavefield in high spatial and temporal resolution. Here, we present data from a month-long, 9 km DAS deployment extending through the ablation and accumulation zones on Rhonegletscher, Switzerland, during the 2020 melt season. While testing several types of machine learning (ML) models, we establish a regression problem, using the DAS data as the dependent variable, to infer the glacier discharge observed at a proglacial stream gauge. We also compare two predictive models that only depend on meteorological station data. We find that the seismo-acoustic wavefield recorded by DAS can be utilized to infer proglacial discharge. Models using DAS data outperform the two models trained on meteorological data with mean absolute errors of 0.64, 2.25 and 2.72 m3 s−1, respectively. This study demonstrates the ability of in situ glacier DAS to be used for quantifying proglacial discharge and points the way to a new approach to measuring glacier runoff.","PeriodicalId":15981,"journal":{"name":"Journal of Glaciology","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142216894","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

Vulnerability of firn to hydrofracture: poromechanics modeling 枞树对水力断裂的脆弱性：孔力学建模

IF 3.4 3区地球科学

Journal of Glaciology Pub Date : 2024-06-05 DOI: 10.1017/jog.2024.47

Yue Meng, R. Culberg, Ching-Yao Lai

引用次数: 0

Improvements on the discretisation of boundary conditions to the momentum balance for glacial ice 冰川冰动量平衡边界条件离散化的改进

IF 3.4 3区地球科学

Journal of Glaciology Pub Date : 2024-06-04 DOI: 10.1017/jog.2024.45

Constantijn J. Berends, R. V. D. van de Wal, P. Zegeling

引用次数: 0

Diverse behaviors of marine ice sheets in response to temporal variability of the atmospheric and basal conditions 海洋冰原因大气和基底条件的时间变化而表现出的不同行为

IF 3.4 3区地球科学

Journal of Glaciology Pub Date : 2024-06-03 DOI: 10.1017/jog.2024.43

O. Sergienko, Duncan Wingham

引用次数: 0

Signal characteristics of surface seismic explosive sources near the West Antarctic Ice Sheet divide 南极西部冰原分界线附近地表地震爆炸源的信号特征

IF 3.4 3区地球科学

Journal of Glaciology Pub Date : 2024-05-08 DOI: 10.1017/jog.2024.41

Marianne Karplus, Nori Nakata, G. Kaip, Steven H. Harder, Lucia F. Gonzalez, Adam D. Booth, Emma C. Smith, S. Veitch, Jacob I. Walter, Poul Christoffersen

引用次数: 0