Stratigraphy of Lake Vida, Antarctica: hydrologic implications of 27 m of ice
Summary: Lake Vida is one of the largest lakes in the McMurdo dry valleys, Antarctica, and has the thickest known ice cover of any lake on Earth. For the first time, Lake Vida was drilled to a depth of 27m. With depth the ice cover changes from freshwater ice to salty ice interspersed with thick sediment layers. It is hypothesized that the repetition of sediment layers in the ice will reveal climatic and hydrologic variability in the region over the last 1000--3000 years.
H. A. Dugan, P. T. Doran, B. Wagner, F. Kenig, C. H. Fritsen, S. A. Arcone, E. Kuhn, N. E. Ostrom, J. P. Warnock, and A. E. Murray The Cryosphere, 9, 439-450, doi:10.5194/tc-9-439-2015, 2015 AbstractFinal Revised Paper (PDF, 7207 KB)Discussion Paper (TCD)
04 Mar 2015
Low below-ground organic carbon storage in a subarctic Alpine permafrost environment
Large-area land surface simulations in heterogeneous terrain driven by global data sets: application to mountain permafrost
Summary: This paper demonstrates a new land surface modelling approach that uses globally available data sets to generate high-resolution simulation results of land surface processes. We successfully simulate a highly resolution-dependent variable, ground surface temperatures, over the entire Swiss Alps at high resolution. We use a large evaluation data set to test the model. We suggest that this scheme represents a useful step in application of numerical models over large areas in heterogeneous terrain.
Assessment of sea ice simulations in the CMIP5 models
Summary: We evaluated all CMIP5 sea-ice simulations with more metrics in both the Antarctic and the Arctic, in an attempt to provide the community a useful reference. Generally speaking, our study shows that the performance of an Arctic sea-ice simulation is better than that of an Antarctic sea-ice simulation, that sea-ice extent simulation is better than sea-ice volume simulation, and that mean-state simulation is better than long-term trend simulation.
Seismic wave propagation in anisotropic ice – Part 2: Effects of crystal anisotropy in geophysical data
A. Diez, O. Eisen, C. Hofstede, A. Lambrecht, C. Mayer, H. Miller, D. Steinhage, T. Binder, and I. Weikusat The Cryosphere, 9, 385-398, doi:10.5194/tc-9-385-2015, 2015 AbstractFinal Revised Paper (PDF, 4826 KB)Discussion Paper (TCD)
20 Feb 2015
Seismic wave propagation in anisotropic ice – Part 1: Elasticity tensor and derived quantities from ice-core properties
Comparing C- and L-band SAR images for sea ice motion estimation
Summary: Satellite radar images are used for detecting and quantifying the motion of sea ice. Traditionally C-band radar images have been used for this purpose. The technique has been shown to work with other frequency bands. This work compares C-band and L-band images for the Baltic Sea. We also show that two images of different bands can be used for sea ice motion estimation.
Seasonal changes in surface albedo of Himalayan glaciers from MODIS data and links with the annual mass balance
F. Brun, M. Dumont, P. Wagnon, E. Berthier, M. F. Azam, J. M. Shea, P. Sirguey, A. Rabatel, and Al. Ramanathan The Cryosphere, 9, 341-355, doi:10.5194/tc-9-341-2015, 2015 AbstractFinal Revised Paper (PDF, 3203 KB)Discussion Paper (TCD)
13 Feb 2015
Measurements of light-absorbing particles on the glaciers in the Cordillera Blanca, Peru
Summary: This paper presents the results of 3 years of measurements of light absorbing particles on the glaciers in Peru. A new analysis technique has been developed and results are shown to be well correlated with black carbon mass estimates made with the Single Particle Soot Photometer (SP2) instrument, the state-of-the-art instrument for this type of measurement. Effective black carbon levels were found to be moderate on glaciers near cities and close to zero in more remote regions.
C. G. Schmitt, J. D. All, J. P. Schwarz, W. P. Arnott, R. J. Cole, E. Lapham, and A. Celestian The Cryosphere, 9, 331-340, doi:10.5194/tc-9-331-2015, 2015 AbstractFinal Revised Paper (PDF, 2431 KB)Discussion Paper (TCD)
Cloud and precipitation properties from ground-based remote-sensing instruments in East Antarctica
Summary: Our paper presents a new cloud-precipitation-meteorological observatory established in the escarpment zone of Dronning Maud Land, East Antarctica. The site is characterised by bimodal cloud occurrence (clear sky or overcast) with liquid-containing clouds occurring 20% of the cloudy periods. Local surface mass balance strongly depends on rare intense snowfall events. A substantial part of the accumulated snow is removed by surface and drifting snow sublimation and wind-driven snow erosion.
I. V. Gorodetskaya, S. Kneifel, M. Maahn, K. Van Tricht, W. Thiery, J. H. Schween, A. Mangold, S. Crewell, and N. P. M. Van Lipzig The Cryosphere, 9, 285-304, doi:10.5194/tc-9-285-2015, 2015 AbstractFinal Revised Paper (PDF, 3457 KB)Supplement (43817 KB)Discussion Paper (TCD)
11 Feb 2015
Arctic sea ice thickness loss determined using subsurface, aircraft, and satellite observations
Summary: The sea ice thickness of the Arctic Basin is estimated from sources that include upward-looking sonars, electromagnetic sensors, and lidar or radar altimeters. Good agreement is found between five of the systems while larger systematic differences are found for others. The trend in annual mean ice thickness, 2000--2013, is –0.58–/+0.07m decade–1; for the central Arctic Basin alone the annual mean ice thickness has decreased from 3.45m in 1975 to 1.11m in 2013, a 68% reduction.
Regional melt-pond fraction and albedo of thin Arctic first-year drift ice in late summer
Summary: Regional melt pond coverage and albedo of thin (70-90cm) first year Arctic sea ice in advanced stage of melt was estimated from a combination of low-altitude imagery and in situ measurements north of Svalbard in summer 2012. The study revealed a homogeneous melt across the study area with a typical pond fraction of 0.29 and sea-ice albedo of 0.44. A decrease in pond fraction was, however, observed in the 30km marginal ice zone, occurring in parallel with an increase in open-water coverage.
Heat sources within the Greenland Ice Sheet: dissipation, temperate paleo-firn and cryo-hydrologic warming
Summary: We analyze the thermal structure of the Greenland Ice Sheet with a heat flow model. New borehole measurements indicate that more heat is stored within the ice than would be expected from heat diffusion alone. We conclude that temperate paleo-firn and cyro-hydrologic warming are essential processes that explain the measurements.
M. P. Lüthi, C. Ryser, L. C. Andrews, G. A. Catania, M. Funk, R. L. Hawley, M. J. Hoffman, and T. A. Neumann The Cryosphere, 9, 245-253, doi:10.5194/tc-9-245-2015, 2015 AbstractFinal Revised Paper (PDF, 1911 KB)Discussion Paper (TCD)
09 Feb 2015
Snow depth mapping in high-alpine catchments using digital photogrammetry
Summary: We are able to map snow depth over large areas ( > 100km2) using airborne digital photogrammetry. Digital photogrammetry is more economical than airborne Laser Scanning but slightly less accurate. Comparisons to independent snow depth measurements reveal an accuracy of about 30cm. Spatial continuous mapping of snow depth is a major step forward compared to point measurements usually applied today. Limitations are steep slopes (> 50°) and areas covered by trees and scrubs.
Enthalpy benchmark experiments for numerical ice sheet models
Summary: We present benchmark experiments and analytical solutions to test the implementation of enthalpy and the corresponding boundary conditions in numerical ice sheet models. The results of the applied models agree well with the analytical solutions if the change in conductivity between cold and temperate ice is properly considered in the model.
Simulating the Greenland ice sheet under present-day and palaeo constraints including a new discharge parameterization
Summary: Ice discharge into the ocean from outlet glaciers is an important
component of mass loss of the Greenland ice sheet. Here, we present a
simple parameterization of ice discharge for coarse resolution ice
sheet models, suitable for large ensembles or long-term palaeo
simulations. This parameterization reproduces in a good approximation
the present-day ice discharge compared with estimates, and the
simulation of the present-day ice sheet elevation is considerably
Observing Muostakh disappear: permafrost thaw subsidence and erosion of a ground-ice-rich island in response to arctic summer warming and sea ice reduction
Summary: Coastal erosion rates at Muostakh Island (eastern Siberian Arctic) have doubled, based on remotely sensed observations of land loss, and therefore the island will disappear prematurely. Based on analyses of seasonal variability of permafrost thaw, thermo-erosion increases by 1.2m per year when summer temperatures rise by 1°C. Due to rapid permafrost thaw, the land surface is subsiding up to 11cm per year, based on comparison of elevation changes and active layer thaw depth.
F. Günther, P. P. Overduin, I. A. Yakshina, T. Opel, A. V. Baranskaya, and M. N. Grigoriev The Cryosphere, 9, 151-178, doi:10.5194/tc-9-151-2015, 2015 AbstractFinal Revised Paper (PDF, 17486 KB)Discussion Paper (TCD)
28 Jan 2015
Mass changes in Arctic ice caps and glaciers: implications of regionalizing elevation changes
Summary: The aim of this study is to determine and quantify the impact of different regionalization schemes on surface elevation changes, and how they affect the estimated spread in mass balance of Arctic ice caps and glaciers. The study found that the choice of regionalization has an important effect in regions with maritime climate and high variability in elevation change. In these areas the spread in mass balance was in many cases larger than the estimated errors of the individual methods.