首页 > 最新文献

Journal of Glaciology最新文献

英文 中文
The speedup of Pine Island Ice Shelf between 2017 and 2020: revaluating the importance of ice damage 2017 - 2020年松岛冰架的加速:冰损重要性的重新评估
3区 地球科学 Q1 Earth and Planetary Sciences Pub Date : 2023-10-09 DOI: 10.1017/jog.2023.76
Sainan Sun, G. Hilmar Gudmundsson
Abstract From 2017 to 2020, three significant calving events took place on Pine Island Glacier, West Antarctica. Ice-shelf velocities changed over this period and the calving events have been suggested as possible drivers. However, satellite observations also show significant changes in the areal extent of fracture zones, especially in the marginal areas responsible for providing lateral support to the ice shelf. Here, we conduct a model study to identify and quantify drivers of recent ice-flow changes of the Pine Island Ice Shelf. In agreement with recent studies, we find that the calving events caused significant velocity changes over the ice shelf. However, calving alone cannot explain observed velocity changes. Changes in the structural rigidity, i.e. ice damage, further significantly impacted ice flow. We suggest that ice damage evolution of the ice-shelf margins may have influenced recent calving events, and these two processes are linked.
2017年至2020年,南极西部松岛冰川发生了三次重大的产犊事件。冰架的速度在这一时期发生了变化,而裂冰事件被认为是可能的驱动因素。然而,卫星观测也显示,断裂带的面积范围发生了显著变化,特别是在为冰架提供横向支撑的边缘地区。在这里,我们进行了一个模型研究,以确定和量化松岛冰架最近冰流变化的驱动因素。与最近的研究一致,我们发现冰裂事件引起了冰架上显著的速度变化。然而,单靠产犊不能解释观测到的速度变化。结构刚度的变化,即冰损伤,进一步显著影响冰流。我们认为冰架边缘的冰损演化可能影响了最近的冰裂事件,这两个过程是相互联系的。
{"title":"The speedup of Pine Island Ice Shelf between 2017 and 2020: revaluating the importance of ice damage","authors":"Sainan Sun, G. Hilmar Gudmundsson","doi":"10.1017/jog.2023.76","DOIUrl":"https://doi.org/10.1017/jog.2023.76","url":null,"abstract":"Abstract From 2017 to 2020, three significant calving events took place on Pine Island Glacier, West Antarctica. Ice-shelf velocities changed over this period and the calving events have been suggested as possible drivers. However, satellite observations also show significant changes in the areal extent of fracture zones, especially in the marginal areas responsible for providing lateral support to the ice shelf. Here, we conduct a model study to identify and quantify drivers of recent ice-flow changes of the Pine Island Ice Shelf. In agreement with recent studies, we find that the calving events caused significant velocity changes over the ice shelf. However, calving alone cannot explain observed velocity changes. Changes in the structural rigidity, i.e. ice damage, further significantly impacted ice flow. We suggest that ice damage evolution of the ice-shelf margins may have influenced recent calving events, and these two processes are linked.","PeriodicalId":15981,"journal":{"name":"Journal of Glaciology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135095671","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
Radiofrequency ice dielectric measurements at Summit Station, Greenland 格陵兰峰顶站的射频冰介电测量
3区 地球科学 Q1 Earth and Planetary Sciences Pub Date : 2023-10-09 DOI: 10.1017/jog.2023.72
Juan Antonio Aguilar, Patrick Allison, Dave Besson, Abby Bishop, Olga Botner, Sjoerd Bouma, Stijn Buitink, Maddalena Cataldo, Brian A. Clark, Kenny Couberly, Zach Curtis-Ginsberg, Paramita Dasgupta, Simon de Kockere, Krijn D. de Vries, Cosmin Deaconu, Michael A. DuVernois, Anna Eimer, Christian Glaser, Allan Hallgren, Steffen Hallmann, Jordan Christian Hanson, Bryan Hendricks, Jakob Henrichs, Nils Heyer, Christian Hornhuber, Kaeli Hughes, Timo Karg, Albrecht Karle, John L. Kelley, Michael Korntheuer, Marek Kowalski, Ilya Kravchenko, Ryan Krebs, Robert Lahmann, Uzair Latif, Joseph Mammo, Matthew J. Marsee, Zachary S. Meyers, Kelli Michaels, Katharine Mulrey, Marco Muzio, Anna Nelles, Alexander Novikov, Alisa Nozdrina, Eric Oberla, Bob Oeyen, Ilse Plaisier, Noppadol Punsuebsay, Lilly Pyras, Dirk Ryckbosch, Olaf Scholten, David Seckel, Mohammad Ful Hossain Seikh, Daniel Smith, Jethro Stoffels, Daniel Southall, Karen Terveer, Simona Toscano, Delia Tosi, Dieder J. Van Den Broeck, Nick van Eijndhoven, Abigail G. Vieregg, Janna Z. Vischer, Christoph Welling, Dawn R. Williams, Stephanie Wissel, Robert Young, Adrian Zink
Abstract We recently reported on the radio-frequency attenuation length of cold polar ice at Summit Station, Greenland, based on bi-static radar measurements of radio-frequency bedrock echo strengths taken during the summer of 2021. Those data also allow studies of (a) the relative contributions of coherent (such as discrete internal conducting layers with sub-centimeter transverse scale) vs incoherent (e.g. bulk volumetric) scattering, (b) the magnitude of internal layer reflection coefficients, (c) limits on signal propagation velocity asymmetries (‘birefringence’) and (d) limits on signal dispersion in-ice over a bandwidth of ~100 MHz. We find that (1) attenuation lengths approach 1 km in our band, (2) after averaging 10 000 echo triggers, reflected signals observable over the thermal floor (to depths of ~1500 m) are consistent with being entirely coherent, (3) internal layer reflectivities are ≈–60 $to$ –70 dB, (4) birefringent effects for vertically propagating signals are smaller by an order of magnitude relative to South Pole and (5) within our experimental limits, glacial ice is non-dispersive over the frequency band relevant for neutrino detection experiments.
我们最近报道了基于双基地雷达测量2021年夏季射频基岩回波强度的格陵兰峰顶站寒冷极地冰的射频衰减长度。这些数据还允许研究(a)相干(如亚厘米横向尺度的离散内部导电层)与非相干(如体积)散射的相对贡献,(b)内层反射系数的大小,(c)信号传播速度不对称的限制(“双折射”)和(d)在~100 MHz带宽上冰内信号色散的限制。我们发现(1)在我们的波段中衰减长度接近1 km,(2)在平均10000个回波触发后,在热层(深度~1500 m)上可观测到的反射信号与完全相干一致,(3)内层反射率为≈-60 $ $至$ -70 dB,(4)相对于南极,垂直传播信号的双折射效应小了一个数量级,(5)在我们的实验限制内。冰川冰在与中微子探测实验相关的频带上是非色散的。
{"title":"Radiofrequency ice dielectric measurements at Summit Station, Greenland","authors":"Juan Antonio Aguilar, Patrick Allison, Dave Besson, Abby Bishop, Olga Botner, Sjoerd Bouma, Stijn Buitink, Maddalena Cataldo, Brian A. Clark, Kenny Couberly, Zach Curtis-Ginsberg, Paramita Dasgupta, Simon de Kockere, Krijn D. de Vries, Cosmin Deaconu, Michael A. DuVernois, Anna Eimer, Christian Glaser, Allan Hallgren, Steffen Hallmann, Jordan Christian Hanson, Bryan Hendricks, Jakob Henrichs, Nils Heyer, Christian Hornhuber, Kaeli Hughes, Timo Karg, Albrecht Karle, John L. Kelley, Michael Korntheuer, Marek Kowalski, Ilya Kravchenko, Ryan Krebs, Robert Lahmann, Uzair Latif, Joseph Mammo, Matthew J. Marsee, Zachary S. Meyers, Kelli Michaels, Katharine Mulrey, Marco Muzio, Anna Nelles, Alexander Novikov, Alisa Nozdrina, Eric Oberla, Bob Oeyen, Ilse Plaisier, Noppadol Punsuebsay, Lilly Pyras, Dirk Ryckbosch, Olaf Scholten, David Seckel, Mohammad Ful Hossain Seikh, Daniel Smith, Jethro Stoffels, Daniel Southall, Karen Terveer, Simona Toscano, Delia Tosi, Dieder J. Van Den Broeck, Nick van Eijndhoven, Abigail G. Vieregg, Janna Z. Vischer, Christoph Welling, Dawn R. Williams, Stephanie Wissel, Robert Young, Adrian Zink","doi":"10.1017/jog.2023.72","DOIUrl":"https://doi.org/10.1017/jog.2023.72","url":null,"abstract":"Abstract We recently reported on the radio-frequency attenuation length of cold polar ice at Summit Station, Greenland, based on bi-static radar measurements of radio-frequency bedrock echo strengths taken during the summer of 2021. Those data also allow studies of (a) the relative contributions of coherent (such as discrete internal conducting layers with sub-centimeter transverse scale) vs incoherent (e.g. bulk volumetric) scattering, (b) the magnitude of internal layer reflection coefficients, (c) limits on signal propagation velocity asymmetries (‘birefringence’) and (d) limits on signal dispersion in-ice over a bandwidth of ~100 MHz. We find that (1) attenuation lengths approach 1 km in our band, (2) after averaging 10 000 echo triggers, reflected signals observable over the thermal floor (to depths of ~1500 m) are consistent with being entirely coherent, (3) internal layer reflectivities are ≈–60 $to$ –70 dB, (4) birefringent effects for vertically propagating signals are smaller by an order of magnitude relative to South Pole and (5) within our experimental limits, glacial ice is non-dispersive over the frequency band relevant for neutrino detection experiments.","PeriodicalId":15981,"journal":{"name":"Journal of Glaciology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135094130","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
Coupled climate-glacier modelling of the last glaciation in the Alps 阿尔卑斯山末次冰期的耦合气候-冰川模拟
3区 地球科学 Q1 Earth and Planetary Sciences Pub Date : 2023-10-06 DOI: 10.1017/jog.2023.74
Guillaume Jouvet, Denis Cohen, Emmanuele Russo, Jonathan Buzan, Christoph C. Raible, Wilfried Haeberli, Sarah Kamleitner, Susan Ivy-Ochs, Michael A. Imhof, Jens K. Becker, Angela Landgraf, Urs H. Fischer
Abstract Our limited knowledge of the climate prevailing over Europe during former glaciations is the main obstacle to reconstruct the past evolution of the ice coverage over the Alps by numerical modelling. To address this challenge, we perform a two-step modelling approach: First, a regional climate model is used to downscale the time slice simulations of a global earth system model in high resolution, leading to climate snapshots during the Last Glacial Maximum (LGM) and the Marine Isotope Stage 4 (MIS4). Second, we combine these snapshots and a climate signal proxy to build a transient climate over the last glacial period and force the Parallel Ice Sheet Model to simulate the dynamical evolution of glaciers in the Alps. The results show that the extent of modelled glaciers during the LGM agrees with several independent key geological imprints, including moraine-based maximal reconstructed glacial extents, known ice transfluences and trajectories of erratic boulders of known origin and deposition. Our results highlight the benefit of multiphysical coupled climate and glacier transient modelling over simpler approaches to help reconstruct paleo glacier fluctuations in agreement with traces they have left on the landscape.
我们对前冰期欧洲气候的有限了解是通过数值模拟重建阿尔卑斯山冰覆盖过去演变的主要障碍。为了应对这一挑战,我们采用了两步建模方法:首先,使用区域气候模式对全球地球系统模式的高分辨率时间片模拟进行缩小,从而获得末次盛冰期(LGM)和海洋同位素阶段4 (MIS4)期间的气候快照。其次,我们将这些快照与气候信号代理相结合,构建末次冰期的瞬态气候,并强迫平行冰盖模式模拟阿尔卑斯冰川的动态演变。结果表明,LGM期间模拟冰川的范围与几个独立的关键地质印记一致,包括基于冰碛的最大重建冰川范围、已知的冰流和已知起源和沉积的不规则巨石的轨迹。我们的研究结果强调了多物理耦合气候和冰川瞬态建模的好处,而不是更简单的方法来帮助重建古冰川波动,以符合它们在景观上留下的痕迹。
{"title":"Coupled climate-glacier modelling of the last glaciation in the Alps","authors":"Guillaume Jouvet, Denis Cohen, Emmanuele Russo, Jonathan Buzan, Christoph C. Raible, Wilfried Haeberli, Sarah Kamleitner, Susan Ivy-Ochs, Michael A. Imhof, Jens K. Becker, Angela Landgraf, Urs H. Fischer","doi":"10.1017/jog.2023.74","DOIUrl":"https://doi.org/10.1017/jog.2023.74","url":null,"abstract":"Abstract Our limited knowledge of the climate prevailing over Europe during former glaciations is the main obstacle to reconstruct the past evolution of the ice coverage over the Alps by numerical modelling. To address this challenge, we perform a two-step modelling approach: First, a regional climate model is used to downscale the time slice simulations of a global earth system model in high resolution, leading to climate snapshots during the Last Glacial Maximum (LGM) and the Marine Isotope Stage 4 (MIS4). Second, we combine these snapshots and a climate signal proxy to build a transient climate over the last glacial period and force the Parallel Ice Sheet Model to simulate the dynamical evolution of glaciers in the Alps. The results show that the extent of modelled glaciers during the LGM agrees with several independent key geological imprints, including moraine-based maximal reconstructed glacial extents, known ice transfluences and trajectories of erratic boulders of known origin and deposition. Our results highlight the benefit of multiphysical coupled climate and glacier transient modelling over simpler approaches to help reconstruct paleo glacier fluctuations in agreement with traces they have left on the landscape.","PeriodicalId":15981,"journal":{"name":"Journal of Glaciology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135350828","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
JOG volume 69 issue 277 Cover and Back matter JOG卷69期277封面和封底
3区 地球科学 Q1 Earth and Planetary Sciences Pub Date : 2023-10-01 DOI: 10.1017/jog.2023.85
An abstract is not available for this content so a preview has been provided. As you have access to this content, a full PDF is available via the ‘Save PDF’ action button.
此内容的摘要不可用,因此提供了预览。当您可以访问此内容时,可以通过“保存PDF”操作按钮获得完整的PDF。
{"title":"JOG volume 69 issue 277 Cover and Back matter","authors":"","doi":"10.1017/jog.2023.85","DOIUrl":"https://doi.org/10.1017/jog.2023.85","url":null,"abstract":"An abstract is not available for this content so a preview has been provided. As you have access to this content, a full PDF is available via the ‘Save PDF’ action button.","PeriodicalId":15981,"journal":{"name":"Journal of Glaciology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136056112","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
Crevasse density, orientation and temporal variability at Narsap Sermia, Greenland. 格陵兰Narsap Sermia的裂缝密度、方向和时间变化
IF 2.8 3区 地球科学 Q2 GEOGRAPHY, PHYSICAL Pub Date : 2023-10-01 Epub Date: 2023-03-29 DOI: 10.1017/jog.2023.3
Maximillian Van Wyk de Vries, James M Lea, David W Ashmore

Mass loss from iceberg calving at marine-terminating glaciers is one of the largest and most poorly constrained contributors to sea-level rise. However, our understanding of the processes controlling ice fracturing and crevasse evolution is incomplete. Here, we use Gabor filter banks to automatically map crevasse density and orientation through time on a ~150 km2 terminus region of Narsap Sermia, an outlet glacier of the southwest Greenland ice sheet. We find that Narsap Sermia is dominated by transverse (flow-perpendicular) crevasses near the ice front and longitudinal (flow-aligned) crevasses across its central region. Measured crevasse orientation varies on sub-annual timescales by more than 45 in response to seasonal velocity changes, and also on multi-annual timescales in response to broader dynamic changes and glacier retreat. Our results show a gradual up-glacier propagation of the zone of flow-transverse crevassing coincident with frontal retreat and acceleration occurring in 2020/21, in addition to sub-annual crevasse changes primarily in transition zones between longitudinal to transverse crevasse orientation. This provides new insight into the dynamics of crevassing at large marine-terminating glaciers and a potential approach for the rapid identification of glacier dynamic change from a single pair of satellite images.

海洋终止冰川的冰山崩解造成的质量损失是海平面上升的最大和最不受约束的因素之一。然而,我们对控制冰破裂和决口演变的过程的理解是不完整的。在这里,我们使用Gabor过滤库自动绘制格陵兰西南冰盖出口冰川Narsap Sermia约150平方公里终点区域的裂缝密度和随时间的方向。我们发现,Narsap Sermia主要由冰锋附近的横向(垂直流动)决口和中部区域的纵向(对齐流动)决裂组成。测量到的决口方向在亚年度时间尺度上变化超过45$^circ$,以响应季节性速度变化,也在多年时间尺度上响应更广泛的动态变化和冰川退缩。我们的研究结果显示,2020/21年,流动-横向决裂区的冰川逐渐向上传播,与锋面退缩和加速相一致,此外,主要在纵向决裂方向与横向决裂方向之间的过渡区发生亚年度决裂变化。这为大型海洋终端冰川的裂缝动力学提供了新的见解,并为从一对卫星图像中快速识别冰川动态变化提供了一种潜在的方法。
{"title":"Crevasse density, orientation and temporal variability at Narsap Sermia, Greenland.","authors":"Maximillian Van Wyk de Vries, James M Lea, David W Ashmore","doi":"10.1017/jog.2023.3","DOIUrl":"10.1017/jog.2023.3","url":null,"abstract":"<p><p>Mass loss from iceberg calving at marine-terminating glaciers is one of the largest and most poorly constrained contributors to sea-level rise. However, our understanding of the processes controlling ice fracturing and crevasse evolution is incomplete. Here, we use Gabor filter banks to automatically map crevasse density and orientation through time on a ~150 km<sup>2</sup> terminus region of Narsap Sermia, an outlet glacier of the southwest Greenland ice sheet. We find that Narsap Sermia is dominated by transverse (flow-perpendicular) crevasses near the ice front and longitudinal (flow-aligned) crevasses across its central region. Measured crevasse orientation varies on sub-annual timescales by more than 45 in response to seasonal velocity changes, and also on multi-annual timescales in response to broader dynamic changes and glacier retreat. Our results show a gradual up-glacier propagation of the zone of flow-transverse crevassing coincident with frontal retreat and acceleration occurring in 2020/21, in addition to sub-annual crevasse changes primarily in transition zones between longitudinal to transverse crevasse orientation. This provides new insight into the dynamics of crevassing at large marine-terminating glaciers and a potential approach for the rapid identification of glacier dynamic change from a single pair of satellite images.</p>","PeriodicalId":15981,"journal":{"name":"Journal of Glaciology","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11443167/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43996931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
JOG volume 69 issue 277 Cover and Front matter JOG第69卷第277期封面和封面问题
3区 地球科学 Q1 Earth and Planetary Sciences Pub Date : 2023-10-01 DOI: 10.1017/jog.2023.84
An abstract is not available for this content so a preview has been provided. As you have access to this content, a full PDF is available via the ‘Save PDF’ action button.
此内容的摘要不可用,因此提供了预览。当您可以访问此内容时,可以通过“保存PDF”操作按钮获得完整的PDF。
{"title":"JOG volume 69 issue 277 Cover and Front matter","authors":"","doi":"10.1017/jog.2023.84","DOIUrl":"https://doi.org/10.1017/jog.2023.84","url":null,"abstract":"An abstract is not available for this content so a preview has been provided. As you have access to this content, a full PDF is available via the ‘Save PDF’ action button.","PeriodicalId":15981,"journal":{"name":"Journal of Glaciology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136056821","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
Beyond the Stokes approximation: shallow visco-elastic ice-sheet models 超越斯托克斯近似:浅粘弹性冰盖模型
3区 地球科学 Q1 Earth and Planetary Sciences Pub Date : 2023-09-28 DOI: 10.1017/jog.2023.75
Jeremy N. Bassis, Samuel B. Kachuck
Abstract The hypothesis that ice-sheet evolution is only controlled by the long-term non-Newtonian viscous behavior of ice has been challenged by observations indicating that effects like brittle failure, stick-slip sliding, tides and wave action may affect ice-sheet evolution on sub-daily timescales. Over these timescales, the quasi-static-creep approximation is no longer appropriate and elastic effects become important. Simulating elastic effects in ice-sheet models over relevant timescales, however, remains challenging. Here, we show that by including a visco-elastic rheology and reintroducing the oft neglected acceleration term back into the ice-sheet stress balance, we can create a visco-elastic system where the velocity is locally determined and information propagates at the elastic wave speed. Crucially, the elastic wave speed can be treated like an adjustable parameter and set to any value to reproduce a range of phenomena, provided the wave speed is large compared to the viscous velocity. We illustrate the system using three examples. The first two examples demonstrate that the system converges to the steady-state viscous and elastic limits. The third example examines ice-shelf rifting and iceberg calving. This final example hints at the utility of the visco-elastic formulation in treating both long-term evolution and short-term environmental effects.
冰盖演化仅受冰的长期非牛顿粘性行为控制的假设受到了挑战,观测结果表明,脆性破坏、粘滑滑动、潮汐和波浪作用等因素可能在亚日时间尺度上影响冰盖演化。在这些时间尺度上,准静态蠕变近似不再合适,弹性效应变得重要。然而,在相关时间尺度上模拟冰盖模型中的弹性效应仍然具有挑战性。在这里,我们表明,通过包括粘弹性流变并将经常被忽视的加速度项重新引入冰盖应力平衡,我们可以创建一个粘弹性系统,其中速度是局部确定的,信息以弹性波速传播。至关重要的是,弹性波速可以被视为一个可调参数,并且可以设置为任何值来重现一系列现象,只要波速比粘性速度大。我们用三个例子来说明这个系统。前两个算例表明,系统收敛于稳态粘弹性极限。第三个例子考察了冰架裂陷和冰山崩解。最后一个例子暗示了粘弹性公式在处理长期演变和短期环境影响方面的效用。
{"title":"Beyond the Stokes approximation: shallow visco-elastic ice-sheet models","authors":"Jeremy N. Bassis, Samuel B. Kachuck","doi":"10.1017/jog.2023.75","DOIUrl":"https://doi.org/10.1017/jog.2023.75","url":null,"abstract":"Abstract The hypothesis that ice-sheet evolution is only controlled by the long-term non-Newtonian viscous behavior of ice has been challenged by observations indicating that effects like brittle failure, stick-slip sliding, tides and wave action may affect ice-sheet evolution on sub-daily timescales. Over these timescales, the quasi-static-creep approximation is no longer appropriate and elastic effects become important. Simulating elastic effects in ice-sheet models over relevant timescales, however, remains challenging. Here, we show that by including a visco-elastic rheology and reintroducing the oft neglected acceleration term back into the ice-sheet stress balance, we can create a visco-elastic system where the velocity is locally determined and information propagates at the elastic wave speed. Crucially, the elastic wave speed can be treated like an adjustable parameter and set to any value to reproduce a range of phenomena, provided the wave speed is large compared to the viscous velocity. We illustrate the system using three examples. The first two examples demonstrate that the system converges to the steady-state viscous and elastic limits. The third example examines ice-shelf rifting and iceberg calving. This final example hints at the utility of the visco-elastic formulation in treating both long-term evolution and short-term environmental effects.","PeriodicalId":15981,"journal":{"name":"Journal of Glaciology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135386967","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
Constraints on subglacial melt fluxes from observations of active subglacial lake recharge 冰下活湖补给观测对冰下融水通量的制约
3区 地球科学 Q1 Earth and Planetary Sciences Pub Date : 2023-09-26 DOI: 10.1017/jog.2023.70
George Malczyk, Noel Gourmelen, Mauro Werder, Martin Wearing, Dan Goldberg
Abstract Active subglacial lakes provide a rare glimpse of the subglacial environment and hydrological processes at play. Several studies contributed to establishing active subglacial lake inventories and document lake drainage and connection, but few focused on the period between lake drainage when the melt production and transport contribute to the refilling of these lakes. In this study, we employ high-resolution CryoSat-2 altimetry data from 2010 to 2021 to compile an inventory of recharging lakes across Antarctica. We extract recharge rates from these lakes, which serve as a lower limit on subglacial melt production. These recharge rates are compared against predictions obtained by routing modelled subglacial meltwater at the ice-sheet's base. Our findings indicate that modelled recharge rates are consistent with observations in all but one of the investigated lakes, providing a lower bound on geothermal heat fluxes. Lake Cook E2 displays recharge rates far exceeding predictions, indicating that processes are taking place that are currently unaccounted for. Considering recharge in hydrologically connected lake networks instead of individually provides a stricter constraint on melt production. Recharge rates extracted from the Thwaites Lake system suggest that subglacial melt production has been underestimated.
活跃的冰下湖泊提供了对冰下环境和水文过程的罕见一瞥。一些研究有助于建立活跃的冰下湖泊清单,并记录湖泊的排水和联系,但很少关注湖泊排水之间的时间,当融水的产生和运输有助于这些湖泊的补充。在这项研究中,我们使用了2010年至2021年的高分辨率CryoSat-2测高数据来编制南极洲各地补给湖的清单。我们从这些湖泊中提取补给速率,作为冰下融水产生的下限。这些补给速率与通过在冰盖底部模拟冰下融水得到的预测结果进行了比较。我们的研究结果表明,模拟的补给率与除一个外的所有调查湖泊的观测结果一致,提供了地热通量的下限。库克湖E2显示的补给率远远超过预测,表明目前尚未解释的过程正在发生。考虑在水文上相连的湖泊网络中而不是单独考虑补给,对熔体的产生提供了更严格的限制。从斯韦茨湖系统提取的补给速率表明,冰下融水的产生被低估了。
{"title":"Constraints on subglacial melt fluxes from observations of active subglacial lake recharge","authors":"George Malczyk, Noel Gourmelen, Mauro Werder, Martin Wearing, Dan Goldberg","doi":"10.1017/jog.2023.70","DOIUrl":"https://doi.org/10.1017/jog.2023.70","url":null,"abstract":"Abstract Active subglacial lakes provide a rare glimpse of the subglacial environment and hydrological processes at play. Several studies contributed to establishing active subglacial lake inventories and document lake drainage and connection, but few focused on the period between lake drainage when the melt production and transport contribute to the refilling of these lakes. In this study, we employ high-resolution CryoSat-2 altimetry data from 2010 to 2021 to compile an inventory of recharging lakes across Antarctica. We extract recharge rates from these lakes, which serve as a lower limit on subglacial melt production. These recharge rates are compared against predictions obtained by routing modelled subglacial meltwater at the ice-sheet's base. Our findings indicate that modelled recharge rates are consistent with observations in all but one of the investigated lakes, providing a lower bound on geothermal heat fluxes. Lake Cook E2 displays recharge rates far exceeding predictions, indicating that processes are taking place that are currently unaccounted for. Considering recharge in hydrologically connected lake networks instead of individually provides a stricter constraint on melt production. Recharge rates extracted from the Thwaites Lake system suggest that subglacial melt production has been underestimated.","PeriodicalId":15981,"journal":{"name":"Journal of Glaciology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134960933","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
Ice-flow model emulator based on physics-informed deep learning 基于物理信息深度学习的冰流模型仿真器
3区 地球科学 Q1 Earth and Planetary Sciences Pub Date : 2023-09-26 DOI: 10.1017/jog.2023.73
Guillaume Jouvet, Guillaume Cordonnier
Abstract Convolutional neural networks (CNN) trained from high-order ice-flow model realisations have proven to be outstanding emulators in terms of fidelity and computational performance. However, the dependence on an ensemble of realisations of an instructor model renders this strategy difficult to generalise to a variety of ice-flow regimes found in the nature. To overcome this issue, we adopt the approach of physics-informed deep learning, which fuses traditional numerical solutions by finite differences/elements and deep-learning approaches. Here, we train a CNN to minimise the energy associated with high-order ice-flow equations within the time iterations of a glacier evolution model. As a result, our emulator is a promising alternative to traditional solvers thanks to its high computational efficiency (especially on GPU), its high fidelity to the original model, its simplified training (without requiring any data), its capability to handle a variety of ice-flow regimes and memorise previous solutions, and its relatively simple implementation. Embedded into the ‘Instructed Glacier Model’ (IGM) framework, the potential of the emulator is illustrated with three applications including a large-scale high-resolution (2400x4000) forward glacier evolution model, an inverse modelling case for data assimilation, and an ice shelf.
从高阶冰流模型实现中训练的卷积神经网络(CNN)在保真度和计算性能方面已被证明是出色的模拟器。然而,依赖于讲师模型的整体实现使得该策略难以推广到自然界中发现的各种冰流状态。为了克服这个问题,我们采用了基于物理的深度学习方法,它融合了基于有限差分/元素的传统数值解和深度学习方法。在这里,我们训练CNN在冰川演化模型的时间迭代中最小化与高阶冰流方程相关的能量。因此,我们的模拟器是传统求解器的一个有前途的替代品,这要归功于它的高计算效率(特别是在GPU上),对原始模型的高保真度,简化的训练(不需要任何数据),处理各种冰流状态和记忆以前的解决方案的能力,以及相对简单的实现。嵌入到“指示冰川模型”(IGM)框架中,仿真器的潜力通过三个应用程序进行说明,包括大规模高分辨率(2400x4000)正向冰川演化模型,数据同化的逆建模案例和冰架。
{"title":"Ice-flow model emulator based on physics-informed deep learning","authors":"Guillaume Jouvet, Guillaume Cordonnier","doi":"10.1017/jog.2023.73","DOIUrl":"https://doi.org/10.1017/jog.2023.73","url":null,"abstract":"Abstract Convolutional neural networks (CNN) trained from high-order ice-flow model realisations have proven to be outstanding emulators in terms of fidelity and computational performance. However, the dependence on an ensemble of realisations of an instructor model renders this strategy difficult to generalise to a variety of ice-flow regimes found in the nature. To overcome this issue, we adopt the approach of physics-informed deep learning, which fuses traditional numerical solutions by finite differences/elements and deep-learning approaches. Here, we train a CNN to minimise the energy associated with high-order ice-flow equations within the time iterations of a glacier evolution model. As a result, our emulator is a promising alternative to traditional solvers thanks to its high computational efficiency (especially on GPU), its high fidelity to the original model, its simplified training (without requiring any data), its capability to handle a variety of ice-flow regimes and memorise previous solutions, and its relatively simple implementation. Embedded into the ‘Instructed Glacier Model’ (IGM) framework, the potential of the emulator is illustrated with three applications including a large-scale high-resolution (2400x4000) forward glacier evolution model, an inverse modelling case for data assimilation, and an ice shelf.","PeriodicalId":15981,"journal":{"name":"Journal of Glaciology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134904239","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
Seasonal changes in submarine melting mechanisms controlling frontal ablation of Hansbreen, Svalbard 控制斯瓦尔巴群岛汉斯布林锋面消融的海底融化机制的季节变化
3区 地球科学 Q1 Earth and Planetary Sciences Pub Date : 2023-09-26 DOI: 10.1017/jog.2023.69
Michał Ciepły, Dariusz Ignatiuk, Mateusz Moskalik, Jacek Jania, Bartłomiej Luks, Oskar Głowacki, Kacper Wojtysiak
Abstract We describe the annual pattern of frontal ablation driven by submarine melting mechanisms at the Hansbreen terminus: these are reflected in the intensity and spatial distribution of calving events. Analysis of time-lapse images of the Hansbreen front in conjunction with oceanographic and meteorological data shows that calving intensity is driven primarily by seawater temperature. Regression analysis also highlights the importance of air temperature, which we take to be a proxy for surface ablation and subglacial discharge. This, combined with seasonal changes in ice cliff tortuosity and the increasing significance of wave motion outside the ablation season, enabled us to determine seasonal changes in the mechanisms of ice cliff undercutting by submarine melting. While submarine melting controlled by estuarine circulation primarily drives frontal ablation in summer, wave-driven melting at the waterline is more important outside the ablation season. During winter, ice cliff undercutting by melting is suspended by low seawater temperature, negligible subglacial water discharge and sea-ice cover. The most intense frontal ablation, recorded in summer, was related to higher sea temperature and vigorous estuarine circulation.
我们描述了在汉斯布林末端海底融化机制驱动的锋面消融的年模式:这些模式反映在产冰事件的强度和空间分布上。结合海洋学和气象资料,对汉斯布林锋的延时图像进行分析,表明产犊强度主要是由海水温度驱动的。回归分析还强调了气温的重要性,我们认为气温是地表消融和冰下流量的代表。结合冰崖弯曲度的季节变化和消融季节之外波浪运动的日益重要的意义,使我们能够确定海底融化冰崖破坏机制的季节变化。在夏季,由河口环流控制的海底融化主要驱动锋面消融,而在消融季节之外,波浪驱动的水线融化更为重要。在冬季,由于海水温度较低,冰下水量和海冰覆盖可忽略不计,冰崖的融化被暂停。记录到的最强烈的锋面消融发生在夏季,与较高的海温和旺盛的河口环流有关。
{"title":"Seasonal changes in submarine melting mechanisms controlling frontal ablation of Hansbreen, Svalbard","authors":"Michał Ciepły, Dariusz Ignatiuk, Mateusz Moskalik, Jacek Jania, Bartłomiej Luks, Oskar Głowacki, Kacper Wojtysiak","doi":"10.1017/jog.2023.69","DOIUrl":"https://doi.org/10.1017/jog.2023.69","url":null,"abstract":"Abstract We describe the annual pattern of frontal ablation driven by submarine melting mechanisms at the Hansbreen terminus: these are reflected in the intensity and spatial distribution of calving events. Analysis of time-lapse images of the Hansbreen front in conjunction with oceanographic and meteorological data shows that calving intensity is driven primarily by seawater temperature. Regression analysis also highlights the importance of air temperature, which we take to be a proxy for surface ablation and subglacial discharge. This, combined with seasonal changes in ice cliff tortuosity and the increasing significance of wave motion outside the ablation season, enabled us to determine seasonal changes in the mechanisms of ice cliff undercutting by submarine melting. While submarine melting controlled by estuarine circulation primarily drives frontal ablation in summer, wave-driven melting at the waterline is more important outside the ablation season. During winter, ice cliff undercutting by melting is suspended by low seawater temperature, negligible subglacial water discharge and sea-ice cover. The most intense frontal ablation, recorded in summer, was related to higher sea temperature and vigorous estuarine circulation.","PeriodicalId":15981,"journal":{"name":"Journal of Glaciology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134958164","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
期刊
Journal of Glaciology
全部 Acc. Chem. Res. ACS Applied Bio Materials ACS Appl. Electron. Mater. ACS Appl. Energy Mater. ACS Appl. Mater. Interfaces ACS Appl. Nano Mater. ACS Appl. Polym. Mater. ACS BIOMATER-SCI ENG ACS Catal. ACS Cent. Sci. ACS Chem. Biol. ACS Chemical Health & Safety ACS Chem. Neurosci. ACS Comb. Sci. ACS Earth Space Chem. ACS Energy Lett. ACS Infect. Dis. ACS Macro Lett. ACS Mater. Lett. ACS Med. Chem. Lett. ACS Nano ACS Omega ACS Photonics ACS Sens. ACS Sustainable Chem. Eng. ACS Synth. Biol. Anal. Chem. BIOCHEMISTRY-US Bioconjugate Chem. BIOMACROMOLECULES Chem. Res. Toxicol. Chem. Rev. Chem. Mater. CRYST GROWTH DES ENERG FUEL Environ. Sci. Technol. Environ. Sci. Technol. Lett. Eur. J. Inorg. Chem. IND ENG CHEM RES Inorg. Chem. J. Agric. Food. Chem. J. Chem. Eng. Data J. Chem. Educ. J. Chem. Inf. Model. J. Chem. Theory Comput. J. Med. Chem. J. Nat. Prod. J PROTEOME RES J. Am. Chem. Soc. LANGMUIR MACROMOLECULES Mol. Pharmaceutics Nano Lett. Org. Lett. ORG PROCESS RES DEV ORGANOMETALLICS J. Org. Chem. J. Phys. Chem. J. Phys. Chem. A J. Phys. Chem. B J. Phys. Chem. C J. Phys. Chem. Lett. Analyst Anal. Methods Biomater. Sci. Catal. Sci. Technol. Chem. Commun. Chem. Soc. Rev. CHEM EDUC RES PRACT CRYSTENGCOMM Dalton Trans. Energy Environ. Sci. ENVIRON SCI-NANO ENVIRON SCI-PROC IMP ENVIRON SCI-WAT RES Faraday Discuss. Food Funct. Green Chem. Inorg. Chem. Front. Integr. Biol. J. Anal. At. Spectrom. J. Mater. Chem. A J. Mater. Chem. B J. Mater. Chem. C Lab Chip Mater. Chem. Front. Mater. Horiz. MEDCHEMCOMM Metallomics Mol. Biosyst. Mol. Syst. Des. Eng. Nanoscale Nanoscale Horiz. Nat. Prod. Rep. New J. Chem. Org. Biomol. Chem. Org. Chem. Front. PHOTOCH PHOTOBIO SCI PCCP Polym. Chem.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
0
微信
客服QQ
Book学术公众号 扫码关注我们
反馈
×
意见反馈
请填写您的意见或建议
请填写您的手机或邮箱
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
Book学术官方微信
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术
文献互助 智能选刊 最新文献 互助须知 联系我们:info@booksci.cn
Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。
Copyright © 2023 Book学术 All rights reserved.
ghs 京公网安备 11010802042870号 京ICP备2023020795号-1