Annals of Glaciology最新文献_第4页

Glacier retreat, dynamics and bed overdeepenings of Parkachik Glacier, Ladakh Himalaya, India 印度拉达克喜马拉雅帕卡奇克冰川的冰川退缩、动力学和河床超深

IF 2.9 4区地球科学

Annals of Glaciology Pub Date : 2023-07-18 DOI: 10.1017/aog.2023.50

Ajay Singh Rana, Pankaj Kunmar, M. Mehta, Vinit Kumar

{"title":"Glacier retreat, dynamics and bed overdeepenings of Parkachik Glacier, Ladakh Himalaya, India","authors":"Ajay Singh Rana, Pankaj Kunmar, M. Mehta, Vinit Kumar","doi":"10.1017/aog.2023.50","DOIUrl":"https://doi.org/10.1017/aog.2023.50","url":null,"abstract":"\u0000 This study describes the morphological and dynamic changes of Parkachik Glacier, Suru River valley, Ladakh Himalaya, India. We used medium-resolution satellite images; CORONA KH-4, Landsat and Sentinel-2A from 1971–2021, and field surveys between 2015 and 2021. In addition, we used the laminar flow-based Himalayan Glacier Thickness Mapper and provide results for recent margin fluctuations, surface ice velocity, ice thickness, and identified glacier-bed overdeepenings. The results revealed that overall the glacier retreated by −210.5 ± 80 m with an average rate of 4 ± 1 m a−1 between 1971 and 2021. Whereas a field study suggested that the glacier retreat increased to −123 ± 72 m at an average rate of −20 ± 12 m a−1 between 2015 and 2021. Surface ice velocity was estimated using COSI-Corr on the Landsat data. Surface ice velocity in the lower ablation zone was 45 ± 2 m a−1 in 1999–2000 and 32 ± 1 m a−1 in 2020–2021, thus reduced by 28%. Further, the maximum thickness of the glacier is estimated to be ~441 m in the accumulation zone, while for glacier tongue it is ~44 m. The simulation results suggest that if the glacier continues to retreat at a similar rate, three lakes of different dimensions may form in subglacial overdeepenings.","PeriodicalId":8211,"journal":{"name":"Annals of Glaciology","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2023-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42409441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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

Inequalities of ice loss: a framework for addressing sociocryospheric change 冰损失的不平等：应对社会冰冻圈变化的框架

IF 2.9 4区地球科学

Annals of Glaciology Pub Date : 2023-07-11 DOI: 10.1017/aog.2023.44

Mark Carey, H. Moulton

{"title":"Inequalities of ice loss: a framework for addressing sociocryospheric change","authors":"Mark Carey, H. Moulton","doi":"10.1017/aog.2023.44","DOIUrl":"https://doi.org/10.1017/aog.2023.44","url":null,"abstract":"\u0000 Cryospheric change occurs in unequal spaces. Societies living near ice are divided by race, class, gender, geography, politics and other factors. Consequently, impacts of ice loss are not shared equally, and everyone experiences cryospheric changes differently. Responsibility for recent ice loss is also driven by a relatively small portion of humanity: those who emit the most greenhouse gases. Additionally, people who study the cryosphere come from institutions and societies where inequality is often systemic, making research on ice and snow a symptom of and contributor to social inequality. To better understand unequal effects of cryospheric change within and across diverse communities, including research communities, this paper focuses on three areas, drawing primarily from glacier-related work: (1) the social context of cryospheric changes; (2) attribution and responsibility for cryospheric changes and (3) imbalances in knowledge about the cryosphere. Addressing these dimensions of ice loss requires transdisciplinary approaches that connect research to societies and link glaciology and other cryospheric sciences with social sciences and humanities. These concepts, cases and suggestions to help address inequalities also reveal that no singular conceptualization of sustainability exists. Different societies, residents and researchers possess distinct understandings of and goals for ‘ice in a sustainable society’.","PeriodicalId":8211,"journal":{"name":"Annals of Glaciology","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2023-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49548341","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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

Glide-snow avalanche characteristics at different timescales extracted from time-lapse photography 从延时摄影中提取不同时间尺度的滑翔雪崩特征

IF 2.9 4区地球科学

Annals of Glaciology Pub Date : 2023-07-11 DOI: 10.1017/aog.2023.37

Amelie Fees, A. van Herwijnen, M. Altenbach, Michael Lombardo, J. Schweizer

{"title":"Glide-snow avalanche characteristics at different timescales extracted from time-lapse photography","authors":"Amelie Fees, A. van Herwijnen, M. Altenbach, Michael Lombardo, J. Schweizer","doi":"10.1017/aog.2023.37","DOIUrl":"https://doi.org/10.1017/aog.2023.37","url":null,"abstract":"\u0000 Glide-snow avalanches release due to a loss of friction at the snow–ground interface, which can result in large avalanches that endanger infrastructure in alpine regions. The underlying processes are still relatively poorly understood, in part due to the limited data available on glide processes. Here, we introduce a pixel-based algorithm to detect glide cracks in time-lapse photographs under changing illumination and shadow conditions. The algorithm was applied to 14 years of time-lapse images at Dorfberg (Davos, Switzerland). We analysed 947 glide-snow events at a high-spatial (0.5 m) and temporal (2–15 min) resolution. Avalanche activity and glide-crack opening dynamics were investigated across timescales ranging from seasonally to hourly. Events were separated into surface (meltwater percolation) and interface events (no meltwater percolation). The results show that glide activity is highly variable between and within seasons. Most avalanches released without crack formation or within 24 h after crack opening, and release was favoured in the afternoon hours. Glide rates often showed a stick–slip behaviour. The acceleration of glide rates and non-constant increases in glide crack aspect ratio were indicators for avalanche release. This comprehensive dataset provides the basis for further investigations into glide-snow avalanche drivers.","PeriodicalId":8211,"journal":{"name":"Annals of Glaciology","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2023-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47801466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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

C and K band microwave penetration into snow on sea ice studied with off-the-shelf tank radars 用现成的坦克雷达研究了C和K波段微波对海冰雪的穿透

IF 2.9 4区地球科学

Annals of Glaciology Pub Date : 2023-07-06 DOI: 10.1017/aog.2023.47

Arttu Jutila, C. Haas

{"title":"C and K band microwave penetration into snow on sea ice studied with off-the-shelf tank radars","authors":"Arttu Jutila, C. Haas","doi":"10.1017/aog.2023.47","DOIUrl":"https://doi.org/10.1017/aog.2023.47","url":null,"abstract":"\u0000 Snow cover on sea ice poses a challenge for radar measurements as microwave penetration into snow is not yet fully understood. In this study, the aim is to investigate microwave penetration into snow on Arctic sea ice using commercial C (6 GHz) and K (26 GHz) band tank radars. Nadir-looking radar measurements collected at nine study locations over first-year and multiyear landfast sea ice in the Lincoln Sea in May 2018 are analysed together with detailed measurements of the physical properties of the snow cover to determine the dominant scattering horizons at both frequencies. They are evaluated for the feasibility to determine snow depth. The results show that in 39% of the measurements and only on first-year ice a major fraction of the C band radar backscatter originated closer to the snow–ice interface potentially enabling snow depth retrieval. At K band, 81% of the radar returns originated from the snow surface. Partly confirming the findings of previous studies, however, the analysis was potentially hampered by relatively warm air temperatures (up to \u0000 \u0000 $-0.9^circ$\u0000 \u0000 \u0000 C) during the study period as well as stratigraphic features and inconclusive microwave interaction with the saline basal layers found in the snow cover on first-year ice.","PeriodicalId":8211,"journal":{"name":"Annals of Glaciology","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2023-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47579339","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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

Two decades of mass-balance observations on Aldegondabreen, Spitsbergen: interannual variability and sensitivity to climate change 斯匹次卑尔根Aldegondabreen岛20年的质量平衡观测:年际变率和对气候变化的敏感性

IF 2.9 4区地球科学

Annals of Glaciology Pub Date : 2023-06-22 DOI: 10.1017/aog.2023.40

A. Terekhov, U. Prokhorova, S. Verkulich, V. Demidov, O. Sidorova, Mikhail Anisimov, Kseniia Romashova

{"title":"Two decades of mass-balance observations on Aldegondabreen, Spitsbergen: interannual variability and sensitivity to climate change","authors":"A. Terekhov, U. Prokhorova, S. Verkulich, V. Demidov, O. Sidorova, Mikhail Anisimov, Kseniia Romashova","doi":"10.1017/aog.2023.40","DOIUrl":"https://doi.org/10.1017/aog.2023.40","url":null,"abstract":"\u0000 Aldegondabreen is a relatively small (5.3 km2) land-terminating glacier located in Nordeskiöld Land of Svalbard, ~10 km southwest of Barentsburg. Cumulative mass balance during 2002–20 equalled −21.79 m w.e., which corresponds to 37% of the total mass loss. The annual mass balance (Ba) varied from −0.24 to −2.19 m w.e., while the winter mass balance (Bw) ranged between 0.36 and 0.85 m w.e. Ba and Bw were strongly correlated with the positive degree-day sums and solid precipitation amounts, respectively, measured at the Barentsburg weather station. There was also a strong correlation (r = 0.76) between Ba and Bw, which shows that winter accumulation amplifies the consecutive summer ice melt by changing the surface albedo. The trend in both observational series is not detectable because the period from 2005 to 2013 was characterized by relatively high Bw and not very negative Ba values. This was also observed on the other Svalbard glaciers, and was related to prevailing north-westerly flows over Svalbard during the summer. Therefore, the decadal periodicity of the Aldegondabreen mass balance follows general archipelago patterns that are determined by regional-scale factors. Thus, the surface mass-balance time series, which is now the longest one in the central part of the Spitsbergen Island, is representative for the archipelago.","PeriodicalId":8211,"journal":{"name":"Annals of Glaciology","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2023-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42737023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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

Diffuse debris entrainment in glacier, lab and model environments 冰川、实验室和模型环境中的弥漫性碎片夹带

4区地球科学

Annals of Glaciology Pub Date : 2023-06-21 DOI: 10.1017/aog.2023.31

Alan W. Rempel, Dougal D. Hansen, Luke K. Zoet, Colin R. Meyer

{"title":"Diffuse debris entrainment in glacier, lab and model environments","authors":"Alan W. Rempel, Dougal D. Hansen, Luke K. Zoet, Colin R. Meyer","doi":"10.1017/aog.2023.31","DOIUrl":"https://doi.org/10.1017/aog.2023.31","url":null,"abstract":"Abstract Small quantities of liquid water lining triple junctions in polycrystalline glacier ice form connected vein networks that enable material exchange with underlying basal environments. Diffuse debris concentrations commonly observed in ice marginal regions might be attributed to this mechanism. Following recent cryogenic ring-shear experiments, we observed emplacement along grain boundaries of loess particles several tens of microns in size. Here, we describe an idealized model of vein liquid flow to elucidate conditions favoring such particle transport. Gradients in liquid potential drive flow toward colder temperatures and lower solute concentrations, while deviations of the ice stress state from hydrostatic balance produce additional suction toward anomalously low ice pressures. Our model predicts particle entrainment following both modest warming along the basal interface resulting from anticipated natural changes in effective stress, and the interior relaxation of temperature and solute concentration imposed by our experimental protocols. Comparisons with experimental observations are encouraging, but suggest that liquid flow rates are somewhat higher and/or more effective at dragging larger particles than predicted by our idealized model with nominal parameter choices. Diffuse debris entrainment extending several meters above the glacier bed likely requires a more sophisticated treatment that incorporates effects of ice deformation or other processes.","PeriodicalId":8211,"journal":{"name":"Annals of Glaciology","volume":"20 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":"135044493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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

A grid-based model of backwasting of supraglacial ice cliffs on debris-covered glaciers – ADDENDUM 碎屑覆盖冰川上冰崖逆蚀的网格模型-附录

4区地球科学

Annals of Glaciology Pub Date : 2023-06-05 DOI: 10.1017/aog.2023.45

Pascal Buri, Francesca Pellicciotti, Jakob F. Steiner, Evan S. Miles, Walter W. Immerzeel

引用次数: 0

Using a Web Map Service to map Little Ice Age glacier extents at regional scales 使用Web地图服务在区域尺度上绘制小冰河期冰川范围

IF 2.9 4区地球科学

Annals of Glaciology Pub Date : 2023-06-02 DOI: 10.1017/aog.2023.39

Johannes Reinthaler, F. Paul

{"title":"Using a Web Map Service to map Little Ice Age glacier extents at regional scales","authors":"Johannes Reinthaler, F. Paul","doi":"10.1017/aog.2023.39","DOIUrl":"https://doi.org/10.1017/aog.2023.39","url":null,"abstract":"\u0000 Extending the record of glacier area changes into the past improves our understanding of climate change impacts. Although analogue maps showing historic glacier extents are abundant, digital outlines from before the satellite era are sparse as the digitisation of moraines and trimlines on freely available satellite images is challenging. With the now available very high-resolution images provided by Web Map Services (WMS), new doors are open for the precise digitisation. Here, we used the ESRI WMS to digitise Little Ice Age (LIA) glacier extents and present area changes since the LIA in four selected regions along with a detailed uncertainty analysis. We used modern glacier outlines as a starting point and additionally consulted Sentinel-2 images, the ArcticDEM and historic maps for interpretation. Dating records from the literature allowed calculating area change rates. In total, 493 LIA glaciers (4640 km2, now 891 ice bodies with 3590 km2) were digitised, yielding relative area changes of −20% (−0.14% a−1), −15% (−0.10% a−1), −26% (−0.16% a−1) and −61% (−0.19% a−1) for Alaska, Baffin Island, Novaya Zemlya and the tropics, respectively. The ESRI WMS images are a great asset to precisely map moraines and trimlines, but information about the timing of the related extents requires further sources.","PeriodicalId":8211,"journal":{"name":"Annals of Glaciology","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2023-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43825480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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

Persistent overcut regions dominate the terminus morphology of a rapidly melting tidewater glacier 持续的过切区主导着快速融化的潮汐冰川的末端形态

IF 2.9 4区地球科学

Annals of Glaciology Pub Date : 2023-05-29 DOI: 10.1017/aog.2023.38

Nicole Abib, D. Sutherland, J. Amundson, D. Duncan, E. Eidam, R. H. Jackson, C. Kienholz, M. Morlighem, R. Motyka, J. Nash, Bridget Ovall, E. Pettit

{"title":"Persistent overcut regions dominate the terminus morphology of a rapidly melting tidewater glacier","authors":"Nicole Abib, D. Sutherland, J. Amundson, D. Duncan, E. Eidam, R. H. Jackson, C. Kienholz, M. Morlighem, R. Motyka, J. Nash, Bridget Ovall, E. Pettit","doi":"10.1017/aog.2023.38","DOIUrl":"https://doi.org/10.1017/aog.2023.38","url":null,"abstract":"\u0000 Frontal ablation, the combination of submarine melting and iceberg calving, changes the geometry of a glacier's terminus, influencing glacier dynamics, the fate of upwelling plumes and the distribution of submarine meltwater input into the ocean. Directly observing frontal ablation and terminus morphology below the waterline is difficult, however, limiting our understanding of these coupled ice–ocean processes. To investigate the evolution of a tidewater glacier's submarine terminus, we combine 3-D multibeam point clouds of the subsurface ice face at LeConte Glacier, Alaska, with concurrent observations of environmental conditions during three field campaigns between 2016 and 2018. We observe terminus morphology that was predominately overcut (52% in August 2016, 63% in May 2017 and 74% in September 2018), accompanied by high multibeam sonar-derived melt rates (4.84 m d−1 in 2016, 1.13 m d−1 in 2017 and 1.85 m d−1 in 2018). We find that periods of high subglacial discharge lead to localized undercut discharge outlets, but adjacent to these outlets the terminus maintains significantly overcut geometry, with an ice ramp that protrudes 75 m into the fjord in 2017 and 125 m in 2018. Our data challenge the assumption that tidewater glacier termini are largely undercut during periods of high submarine melting.","PeriodicalId":8211,"journal":{"name":"Annals of Glaciology","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2023-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44365231","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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

Using video detection of snow surface movements to estimate weak layer crack propagation speeds 利用视频检测积雪表面运动估计弱层裂纹扩展速度

IF 2.9 4区地球科学

Annals of Glaciology Pub Date : 2023-05-22 DOI: 10.1017/aog.2023.36

Ron Simenhois, K. Birkeland, J. Gaume, A. van Herwijnen, Bastian Bergfeld, B. Trottet, E. Greene

{"title":"Using video detection of snow surface movements to estimate weak layer crack propagation speeds","authors":"Ron Simenhois, K. Birkeland, J. Gaume, A. van Herwijnen, Bastian Bergfeld, B. Trottet, E. Greene","doi":"10.1017/aog.2023.36","DOIUrl":"https://doi.org/10.1017/aog.2023.36","url":null,"abstract":"\u0000 Dry-snow slab avalanches release due to crack propagation in a weak snow layer under a cohesive snow slab. Crack propagation speeds can provide insights into the potential size of avalanches and inform fracture and avalanche release models. Despite their importance, slope-scale crack speed measurements from real avalanches are limited. Further, most existing slope-scale measurements utilize the appearance of slab fractures on the snow surface. However, we have no evidence that the appearance of surface cracking is a good indicator of the weak layer crack propagation tip. Here we present a novel method to estimate crack propagation speed from snow surface movements in avalanche videos. Our technique uses changes in frame pixel intensity, allowing us to detect the location of weak layer cracks well before slab fractures appear on the snow surface. We use field experiments and numerical simulations to validate our method before applying it to five avalanches. Our estimates show that cracks propagate faster up and down the slope than in the cross-slope direction; this suggests that different propagation regimes likely govern crack propagation up/down the slope, cross-slope and in flat terrain.","PeriodicalId":8211,"journal":{"name":"Annals of Glaciology","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2023-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44531008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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