Preprints
Filtering by Subject: Glaciology
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: 2018-12-22
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 [...]
Early Last Interglacial ocean warming drove substantial ice mass loss from Antarctica
Published: 2018-12-07
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics
The future response of the Antarctic ice sheets to rising temperatures remains highly uncertain. A valuable analogue for assessing the sensitivity of Antarctica to warming is the Last Interglacial (129-116 kyr), when global sea level peaked 6 to 9 meters above present. Here we report a blue-ice record of ice-sheet and environmental change from the periphery of the marine-based West Antarctic Ice [...]
A Simple Model for Deglacial Meltwater Pulses
Published: 2018-11-08
Subjects: Earth Sciences, Geophysics and Seismology, Glaciology, Physical Sciences and Mathematics
Evidence from radiocarbon dating and complex ice sheet modeling suggests that the fastest rate of sea level rise in Earths recent history coincided with collapse of the ice saddle between the Laurentide and Cordilleran ice sheets during the last deglaciation. In this study, we derive a simple, two-equation model of two ice sheets intersecting in an ice saddle. We show that two conditions are [...]
Response of Marine-Terminating Glaciers to Forcing: Time Scales, Sensitivities, Instabilities and Stochastic Dynamics
Published: 2018-09-21
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics
Recent observations indicate that many marine‐terminating glaciers in Greenland and Antarctica are currently retreating and thinning, potentially due to long‐term trends in climate forcing. In this study, we describe a simple two‐stage model that accurately emulates the response to external forcing of marine‐terminating glaciers simulated in a spatially extended model. The simplicity of the model [...]
Vibrational modes of hydraulic fractures: Inference of fracture geometry from resonant frequencies and attenuation
Published: 2018-05-28
Subjects: Earth Sciences, Environmental Sciences, Geophysics and Seismology, Glaciology, Physical Sciences and Mathematics, Volcanology
Oscillatory seismic signals arising from resonant vibrations of hydraulic fractures are observed in many geologic systems, including volcanoes, glaciers and ice sheets, and hydrocarbon and geothermal reservoirs. To better quantify the physical dimensions of fluid‐filled cracks and properties of the fluids within them, we study wave motion along a thin hydraulic fracture waveguide. We present a [...]
The land ice contribution to sea level during the satellite era
Published: 2018-05-14
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics
Since 1992, there has been a revolution in our ability to quantify the land ice contribution to SLR using a variety of satellite missions and technologies. Each mission has provided unique, but sometimes conflicting, insights into the mass trends of land ice. Over the last decade, over fifty estimates of land ice trends have been published, providing a confusing and often inconsistent picture. [...]
Application of discrete-element methods to approximate sea-ice dynamics
Published: 2018-02-15
Subjects: Earth Sciences, Glaciology, Oceanography and Atmospheric Sciences and Meteorology, Other Physical Sciences and Mathematics, Physical Sciences and Mathematics
Lagrangian models of sea-ice dynamics have several advantages over Eulerian continuum models. Spatial discretization on the ice-floe scale are natural for Lagrangian models and offer exact solutions for mechanical non-linearities with arbitrary sea-ice concentrations. This allows for improved model performance in ice-marginal zones. Furthermore, Lagrangian models can explicitly simulate jamming [...]
The role of glacier retreat for Swiss hydropower production
Published: 2017-12-22
Subjects: Earth Sciences, Engineering, Environmental Sciences, Glaciology, Hydrology, Natural Resource Economics, Natural Resources Management and Policy, Physical Sciences and Mathematics, Sustainability, Water Resource Management
High elevation or high latitude hydropower production (HP) strongly relies on water resources that are influenced by glacier melt and are thus highly sensitive to climate warming. Despite of the wide-spread glacier retreat since the development of HP infrastructure in the 20th century, little quantitative information is available about the role of glacier mass loss for HP. We provide the first [...]
Ice shelf rift propagation and the mechanics of wave-induced fracture
Published: 2017-11-29
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics
Distant storms, tsunamis, and earthquakes generate waves on floating ice shelves. Previous studies, however, have disagreed about whether the resulting wave-induced stresses may cause ice shelf rift propagation. Most ice shelf rifts show long periods of dormancy suggesting that they have low background stress concentrations and may therefore be susceptible to wave-induced stresses. Here, I [...]
Temperatures recorded by cosmogenic noble gases since the last glacial maximum in the Maritime Alps
Published: 2017-11-24
Subjects: Earth Sciences, Geochemistry, Geomorphology, Glaciology, Other Earth Sciences, Physical Sciences and Mathematics
While proxy records have been used to reconstruct late Quaternary climate parameters throughout the European Alps, our knowledge of deglacial climate conditions in the Maritime Alps is limited. Here, we report temperatures recorded by a new and independent geochemical technique—cosmogenic noble gas paleothermometry—in the Maritime Alps since the last glacial maximum. We measured cosmogenic 3He in [...]