Preprints
Filtering by Subject: Glaciology
Basal melting over Subglacial Lake Ellsworth and it catchment: insights from englacial layering
Published: 2019-07-25
Subjects: Earth Sciences, Geophysics and Seismology, Glaciology, Hydrology, Physical Sciences and Mathematics
Deep-water ‘stable’ subglacial lakes likely contain microbial life adapted in isolation to extreme environmental conditions. How water is supplied into a subglacial lake, and how water outflows, is important for understanding these conditions. Isochronal radio-echo layers have been used to infer where melting occurs above Lake Vostok and Lake Concordia in East Antarctica but have not been used [...]
The Glacial Origins of Relict Pingos, Wales, UK
Published: 2019-07-04
Subjects: Earth Sciences, Geomorphology, Glaciology, Physical Sciences and Mathematics
Ramparted depressions (doughnut-shaped debris-cored ridges with peat- and/or sediment-filled central basins) are commonly perceived to represent the relict collapsed forms of permafrost ground-ice mounds (i.e. pingos or lithalsas). In Wales, UK, ramparted depressions of Late Pleistocene age have been widely attributed to permafrost-related processes. However, a variety of alternative glacial [...]
Amplified Last-Glacial-Maximum response of Chandra valley (western Himalaya) glaciers
Published: 2019-06-03
Subjects: Earth Sciences, Geomorphology, Glaciology, Physical Sciences and Mathematics
Geomorphological evidence suggests a subdued response of Himalayan glaciers during the Last Glacial Maximum (LGM), with relatively minor advances (~10 km) reported in several glacierised valleys across the region. This supports the hypothesis that a weakened Indian summer monsoon during the LGM largely counterbalanced the effects of a colder climate on Himalayan glaciers. In contrast, a recently [...]
Glacier area and the variability of glacier change
Published: 2019-05-31
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics
This is the preprint of a letter that is under review in the Journal of Glaciology. The abstract is as follows: Large-scale remote-sensing data on ice loss in the Himalaya and other glacierised regions indicate that the differences in glacier area do not significantly influence the glacier-to-glacier variability of the thinning rate. An analysis of the available data from several regions across [...]
Estimation of the total sub-debris ablation from point-scale ablation data on a debris-covered glacier
Published: 2019-05-31
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics
This is the preprint of an article that is under review in the Journal of Glaciology. The abstract is as follows: Glaciological mass balance is computed from point-scale field data at a few ablation stakes that are regressed as a function of elevation, and averaged over the area-elevation distribution of the glacier. This method is contingent on a tight control of elevation on local ablation. On [...]
Marine biomarkers from ice cores reveal enhanced high-latitude Southern Ocean carbon sink during the Antarctic Cold Reversal
Published: 2019-05-31
Subjects: Biogeochemistry, Earth Sciences, Glaciology, Paleontology, Physical Sciences and Mathematics
Determining the feedbacks that modulate Southern Ocean carbon dynamics is key to understanding past and future climate. The global pause in rising atmospheric CO2 during the period of mid- to high-latitude southern surface cooling known as the Antarctic Cold Reversal (ACR, 14,700-12,700 years ago) provides an opportunity to disentangle competing influences. We present highly-resolved and [...]
Equifinality and preservation potential of complex eskers
Published: 2019-03-15
Subjects: Earth Sciences, Geology, Geomorphology, Glaciology, Hydrology, Physical Sciences and Mathematics
Eskers are useful for reconstructing meltwater drainage systems of glaciers and ice sheets. However, our process understanding of eskers suffers from a disconnect between sporadic detailed morpho-sedimentary investigations of abundant large-scale ancient esker systems, and a small number of modern analogues where esker formation has been observed. This paper presents the results of detailed field [...]
Current Problems of Water Supply and Usage in Central Asia, Tian Shan Basin
Published: 2019-02-13
Subjects: Earth Sciences, Ecology and Evolutionary Biology, Environmental Studies, Geography, Geology, Geomorphology, Glaciology, Hydrology, Life Sciences, Other Geography, Physical and Environmental Geography, Physical Sciences and Mathematics, Social and Behavioral Sciences, Spatial Science
The paper focuses on analysis of Central Asian hydro-energetic system and water usage in Tian Shan region. Tian Shan system is an important water resource in Central Asia: river waters are intensely taken for hydropower energy, urban systems, irrigation. But geopolitics in Tian Shan is difficult: it crosses five densely populated countries. The problem consists in water delivery between countries [...]
Supraglacial pond evolution in the Everest region, central Himalaya, 2015-2018.
Published: 2019-01-18
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics
Supraglacial ponds are characteristic of debris-covered glaciers and can greatly enhance local melt rates. They can grow rapidly and coalesce to form proglacial lakes, presenting a major hazard. Here, we use Sentinel-2A satellite imagery (10 m) to quantify the spatiotemporal changes of 6,425 supraglacial ponds for 10 glaciers in Everest region of Nepal between 2015 and 2018. During the study [...]
Supraglacial pond evolution in the Everest region, central Himalaya, 2015-2018.
Published: 2019-01-15
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics
Supraglacial ponds are characteristic of debris-covered glaciers and can greatly enhance local melt rates. They can grow rapidly and coalesce to form proglacial lakes, presenting a major hazard. Here, we use Sentinel-2A satellite imagery (10 m) to quantify the spatiotemporal changes of 6,425 supraglacial ponds for 10 glaciers in Everest region of Nepal between 2015 and 2018. During the study [...]
Neoproterozoic glacial origin of the Great Unconformity
Published: 2019-01-07
Subjects: Earth Sciences, Geochemistry, Geology, Glaciology, Physical Sciences and Mathematics
The Great Unconformity, a profound gap in Earths stratigraphic record often evident below the base of the Cambrian system, has remained among the most enigmatic field observations in Earth science for over a century. While long associated directly or indirectly with the occurrence of the earliest complex animal fossils, a conclusive explanation for the formation and global extent of the Great [...]
Long-term and inter-annual mass changes in the Iceland ice cap determined from GRACE gravity
Published: 2019-01-03
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics
The Gravity Recovery and Climate Experiment (GRACE) satellites have measured anomalies in the Earth’s time-variable gravity field since 2002, allowing for the measurement of the melting of glaciers due to climate change. Many techniques used with GRACE data have difficulty constraining mass change in small regions such as Iceland, often requiring broad averaging functions in order to capture [...]
Exceptional retreat of Kangerlussuaq Glacier, east Greenland, between 2016 and 2018
Published: 2018-12-28
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics
Kangerlussuaq Glacier is one of Greenland’s largest tidewater outlet glaciers, accounting for approximately 5% of all ice discharge from the Greenland ice sheet. In 2018 the Kangerlussuaq ice front reached its most retreated position since observations began in 1932. We determine the relationship between retreat and: (i) ice velocity; and (ii) surface elevation change, to assess the impact of the [...]
Ice shelf stability and the brittle–ductile transition
Published: 2018-12-21
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics
Fracturing processes limit the ability of floating ice shelves to stabilize marine ice sheets. Here, I argue that ice shelves are most susceptible to fracture when their thickness is less than the brittle–ductile transition thickness H*?, defined as the depth at which the overburden pressure equals the local yield strength in tension. A fracture mechanical analysis, compared with time-lapse [...]
The retreat pattern of glaciers controls the occurrence of turbidity currents on high-latitude fjord deltas
Published: 2018-12-12
Subjects: Earth Sciences, Geology, Geomorphology, Glaciology, Physical Sciences and Mathematics, Sedimentology
Glacier and ice sheet mass loss as a result of climate change is driving important coastal changes in Arctic fjords. Yet, limited information exists for Arctic coasts regarding the influence of glacial erosion and ice mass loss on the occurrence and character of turbidity currents in fjords which themselves affect delta dynamics. Here, we show how glacial erosion and the production of meltwaters [...]