Locating a suitable drill site is a key step in the Antarctic oldest-ice challenge. Here we have conducted a 3-D ice flow simulation in the region of Dome C using a refined bedrock description. Five selection criteria are computed that together provide an objective overview on the local ice flow conditions. We delineate kilometer-scale favorable areas that overlap with the ones recently proposed by another group.
We propose a few drill sites that should be surveyed during the next field seasons. In this paper we analyze snow data from Soviet airborne expeditions, Sever, which operated in late winter , in the Arctic and made snow measurements on the ice around plane landing sites. The snow measurements were made on the multiyear ice in the central Arctic and on the first-year ice in the Eurasian seas in the areas for which snow characteristics are poorly described in the literature.
The main goal of this study is to produce an improved data set of snow depth on the sea ice. We find strongly negative mass balances from to for both icefields, in agreement with airborne laser altimetry.
Mass losses are thus continuing unabated. Coupled climate—ice sheet simulations have been growing in popularity in recent years. Experiments of this type are however challenging as ice sheets evolve over multi-millennial timescales, which is beyond the practical integration limit of most Earth system models. A common method to increase model throughput is to trade resolution for computational efficiency compromise accuracy for speed.
Here we analyze how the resolution of an atmospheric general circulation model AGCM influences the simulation quality in a stand-alone ice sheet model. These simulations were subsequently used as forcing of an ice sheet model. Most mountain glaciers have receded throughout the last century in response to global climate change. This recession produces a range of natural hazards including glacial lake outburst floods GLOFs.
We have produced the first global inventory of GLOFs associated with the failure of moraine dams and show, counterintuitively, that these have reduced in frequency over recent decades. In this paper we explore the reasons for this pattern. This work proposes a new data synergy method for the retrieval of sea ice thickness and snow depth by using colocating L-band passive remote sensing and active laser altimetry.
Physical models are adopted for the retrieval, including L-band radiation model and buoyancy relationship. Covariability of snow depth and total freeboard is further utilized to mitigate resolution differences and improve retrievability. This paper makes a rather exhaustive overview of current knowledge of past, current, and future aspects of cryospheric issues in continental Europe and makes a number of reflections of areas of uncertainty requiring more attention in both scientific and policy terms.
The review paper is completed by a bibliography containing recent references that will certainly be of value to scholars engaged in the fields of glacier, snow, and permafrost research. We explain why snow pits across different sites in East Antarctica show visually similar isotopic variations. The near constancy of the diffusion length across many ice-coring sites explains why the structure and cycle length is largely independent of the accumulation conditions.
Geophysical methods have wide applications to permafrost studies. We show that borehole nuclear magnetic resonance is a valuable geophysical tool to rapidly characterize the liquid water content and unfrozen pore space in warm permafrost through simulation and field study. This technique is also sensitive to the ice nucleation process in situ.
This method, which is applicable in a variety of soil types, can be used for single observations or for time-lapse monitoring of permafrost changes. Light-absorbing impurities deposited on snow, such as soot or dust, strongly modify its evolution. Model results were evaluated based on innovative field observations at an Alpine site.
This allows future investigations in the fields of climate, hydrology and avalanche prediction. In this CESM modeling study, we uncover regional relationships in snowfall across Antarctica that are corroborated by regional modeling and ice core records.
VTLS Vectors iPortal Hasil Carian
These relationships are driven by variability in large-scale atmospheric moisture transport and dampen overall Antarctic snowfall variability, with implications for Antarctic-sourced sea level variability and detection of an emergent anthropogenic signal in Antarctic mass trends. We combine a synthesis of 22 ice core records and a model of soluble impurity transport to investigate the enigmatic, post-depositional migration of methanesulfonic acid in polar ice. Our findings suggest that migration may be universal across coastal regions of Greenland and Antarctica, though it is mitigated at sites with higher accumulation and or lower impurity content.
Records exhibiting severe migration may still be useful for inferring decadal and lower-frequency climate variability. Obtaining an older palaeoclimatic record from Antarctica is one of the greatest challenges of the ice core community. Here, we estimate the age of basal ice in the Dome C area. We show mathematically and computationally how discharge of ice from ocean-terminating glaciers is controlled by a combination of different forces acting on ice near the grounding line of a glacier and how that combination of forces is affected by the process of iceberg formation, which limits the length of floating ice tongues extending in front of the glacier.
We show that a deeper fjord may lead to a longer ice tongue providing greater drag on the glacier, slowing the rate of ice discharge. Using these satellite missions together completes the picture of the changing Arctic sea ice and provides a more accurate and comprehensive view on the actual state of Arctic sea-ice thickness.
The Greenland ice sheet melts faster in a warmer climate.
The ice sheet is flatter at high elevation, therefore atmospheric warming increases the melt area exponentially. Meltwater is not stored underneath the ice sheet, as previously found, but it does take multiple days for it to pass through the seasonally developing subglacial drainage channels, moderating discharge. This work defines a metric for evaluation of a specific model snow process, namely, heat transfer through snow into soil. Heat transfer through snow regulates the difference in air temperature versus soil temperature.
Accurate representation of the snow heat transfer process is critically important for accurate representation of the current and future state of permafrost. Utilizing this metric, we can clearly identify models that can and cannot reasonably represent snow heat transfer. Recent surging of Kyagar Glacier Karakoram caused a hazardous ice-dammed lake to form and burst in and We use remotely sensed glacier surface velocities and surface elevation to observe dramatic changes in speed and mass distribution during the surge.
The surge was hydrologically controlled with rapid summer onset and dramatic termination following lake outburst. Since the surge, the potential outburst hazard has remained high, and continued remote monitoring is crucial. We simulate the future snow cover in the Alps with the help of a snow model, which is fed by projected temperature and precipitation changes from a large set of climate models.
We used old US reconnaissance imagery and could show that glaciers in the Hunza River basin Central Karakoram experienced on average no significant mass changes also since the s. Likewise the glaciers had heterogeneous behaviour with frequent surge activities during the last 40 years. In this paper we investigate elevation changes of Thwaites Glacier, West Antarctica, one of the main sources of excess ice discharge into the ocean. Concurrent ice-speed measurements show only minor changes, suggesting that ice dynamics are not strongly sensitive to changes in water flow.
Based on DEM simulations we developed a new model for the onset of crack propagation in snow slab avalanche release. The model reconciles past approaches by considering the complex interplay between slab elasticity and the mechanical behavior of the weak layer including its structural collapse. The model agrees with extensive field data and can reproduce crack propagation on low-angle terrain and the decrease in critical crack length with increasing slope angle observed in numerical experiments.
The absorption of visible light in ice is very weak but its precise value is unknown. We replicated their experiment on a large number of samples and found that ice absorption is at least 10 times stronger. The paper explores various potential physical and statistical biases that could impact the experiment. Here we compare post-calving observations with high-resolution ocean modelling which suggest that this reconfiguration has led to the development of a new polynya off Commonwealth Bay.
The thermal conductivity TC of the snow and top soil greatly impacts the permafrost energy budget. We report the first winter-long monitoring of snow and soil TC in the high Arctic. The data and field observations show the formation of a highly insulating basal depth hoar layer overlaid by a more conductive wind slab. Detailed snow physics models developed for alpine snow cannot reproduce observations because they neglect the strong upward vertical water vapor flux prevailing in Arctic snow.
The reconstruction of past snow accumulation rates is crucial in the context of recent climate change and sea level rise. This study is the first to show an increase in snow accumulation, beginning in the 20th and particularly marked in the last 50 years, thereby confirming model predictions of increased snowfall associated with climate change. This is the first study of recent glacier change for the whole of the Bolivian Cordillera Oriental from to We provide the first quantification of meltwater lake development across the Bolivian Andes as glaciers have receded.
These lakes have increased markedly in number and area. We identify 25 lakes as potential outburst flood risks to downstream communities. These lakes require further monitoring. Here we utilize declassified spy satellite imagery to quantify ice volume loss of glaciers in the eastern Himalayas over approximately the last three decades. Clean-ice and debris-covered glaciers show similar magnitudes of ice loss, while calving glaciers are contributing a disproportionately large amount to total ice loss.
Results highlight important physical processes affecting the ice mass budget and associated water resources in the Himalayas. Understanding air movement inside the firn is critical for ice core climate reconstructions. Media reviews. Current promotions. More Info. Monitoring of Harmful Algae Blooms. Io After Galileo. Seafloor Observatories. Remote Sensing in Snow Hydrology.
Breaking Ocean Waves. Tsunami: The Underrated Hazard. An Introduction to Underwater Acoustics. Bestsellers in Climate Change. Climate Change and British Wildlife. Effects of Climate Change on Birds.
The Little Ice Age. The Uninhabitable Earth. Oceans in Decline. How to Reduce Your Carbon Footprint. Extreme Conservation. The Paris Climate Agreement. The Fate of Greenland. Forests in Our World. Introduction to Three-Dimensional Climate Modeling. Principles of Thermal Ecology. Other titles from Springer.
Plant Ecology. Rewilding European Landscapes. Atlas of Macroscopic Wood Identification. Bats in the Anthropocene. Biological Oceanography of the Baltic Sea. Integrated Assessment of Running Waters in Europe. Browse titles from Springer.
Related Climate Change in Eurasian Arctic Shelf Seas: Centennial Ice Cover Observations
Copyright 2019 - All Right Reserved