Brief Communication: Contending estimates of early 21st century glacier mass balance over the Pamir-Karakoram-Himalaya
Summary: Based on satellite laser altimetry over the Pamir-Karakoram-Himalaya we detect strongest elevation losses over East Nyainqentanglha Shan and Jammu Kashmir, but slight elevation gains over West Kunlun Shan rather than over the Karakoram anomaly. The current sea level contribution of Pamir-Karakoram-Himalaya glaciers is about 10% of the total global contribution of glaciers outside the ice sheets. We also improve estimates of glacier imbalance contribution to river discharge in the Himalayas.
Summary: - Infrared radiation thermography (IRT) was used to assess the surface temperature of avalanches with high spatial resolution.
- Thermal energy increase due to friction was mainly depending on the elevation drop of the avalanche.
- Warming due to entrainment was very specific to the individual avalanche and depends on the temperature of the snow along the path and the erosion depth.
- The warmest temperatures were located in the deposits of the dense core.
Thin-ice dynamics and ice production in the Storfjorden polynya for winter-seasons 2002/2003–2013/2014 using MODIS thermal infrared imagery
Summary: The Storfjorden polynya (Svalbard) forms regularly under the influence of strong north-easterly winds. In this study, spatial and temporal characteristics for the period 2002/03 - 2013/14 were inferred from daily calculated thin-ice thickness distributions, based on MODIS ice surface temperatures and ERA-interim reanalysis.
With an estimated average ice production of 28.3 km³/winter, this polynya system is of particular interest regarding its potential contribution to deep water formation.
Verification of forecasted winter precipitation in complex terrain
Summary: Numerical Weather Prediction (NWP) models are rarely verified for mountainous regions during the winter season, although avalanche forecasters and other decision makers frequently rely on NWP models. We verified two NWP models (GEM-LAM and GEM15) and a precipitation analysis system (CaPA) at approximately 100 stations in the mountains of western Canadian and northwestern US. Ultrasonic snow depth sensors and snow pillows were used to observe daily precipitation amounts.
Factors controlling Slope Environmental Lapse Rate (SELR) of temperature in the monsoon and cold-arid glacio-hydrological regimes of the Himalaya
Summary: Slope environmental lapse rate of temperature in the monsoon and cold-arid regimes of the higher Himalaya is found to be varying between 9.0 to 1.9oC/km and 17.0 to 2.8oC/km respectively highlighting strong regional variability. Moisture availability/absence is found to be the key factor forcing the lapse rate variability. Present study also provided a modelling solution for estimating the lapse rate.Study suggests that the arbitrary use of lapse rate in the Himalaya is is extremely untenable
Snow mass decrease in the Northern Hemisphere (1979/80–2010/11)
Summary: In this manuscript, we verified the snow water equivalent (SWE) products with large amounts of ground stations and generated an optimized SWE product covering (1979/80-2010/11). Using the optimized product it was found that the SWE is significantly decreasing in the past 32 years, and the decreasing is closely related to temperature rising.
Strategy of valid 14C dates choice in syngenetic permafrost
Summary: The strategy of valid 14С dates choice in syngenetic permafrost includes several points such as:
• Re-deposition of organic matter in the permafrost is common. Syngenetic sediments contain allochthonous organic deposit that originated at a distance from its present position. There needs to be a careful cull of the manifestly more ancient 14C dates.
• The youngest 14C date from the data set in the particular horizon is closest to the actual time of accumulation and freezing of the yedoma
Simulating the Antarctic ice sheet in the Late-Pliocene warm period: PLISMIP-ANT, an ice-sheet model intercomparison project
B. de Boer, A. M. Dolan, J. Bernales, E. Gasson, H. Goelzer, N. R. Golledge, J. Sutter, P. Huybrechts, G. Lohmann, I. Rogozhina, A. Abe-Ouchi, F. Saito, and R. S. W. van de Wal The Cryosphere Discuss., 8, 5539-5588, 2014 AbstractDiscussion Paper (PDF, 4338 KB)Supplement (551 KB)Interactive Discussion (Open, 1 Comment)Manuscript under review for TC
05 Nov 2014
Model calibration for ice sheets and glaciers dynamics: a general theory of inverse problems in glaciology
Summary: Inverse problems (IPs) are fundamental to calibrate numerical models, but are not yet widely diffused in glaciology, even if some theroretical developments and excellent applications were published.
This paper provides a conceptual framework for IP in cryospheric sciences, which permits to clearly define and discuss the properties of IP.
The examined topics include: the role of data and parameters: the link of ill-posedness with ill-conditioning and identifiability; sensitivity analysis.
Quantifying meltwater refreezing along a transect of sites on the Greenland Icesheet
Summary: On the Greenland Ice Sheet, a significant quantity of surface melt water refreezes after infiltrating into the cold underlying firn. This paper presents a new method for estimating the amount of water refreezing using temperature measurements. The method is applied to temperature data from a transect of 11 sites and the results provide some of the first measurement based estimates of refreezing quantities which can be used to improve modeling and better understand the refreezing process.
Improving semi-automated glacial mapping with a multi-method approach: areal changes in Central Asia
Summary: We describe and employ a newly developed glacial mapping algorithm which uses spectral, topographic, velocity, and spatial data to quickly and accurately map glacial extents over a wide area. We test this algorithm on glaciers in Central Asia, and show a gradient in glacier area loss rates where those closer to the west (Pamir) are shrinking slower than those towards the east (Tien Shan). We explain this pattern with a noticeable precipitation and storm intensity gradient in the region.
Modelling glacier change in the Everest region, Nepal Himalaya
Summary: Using a glacier mass balance and redistribution model tuned to historical data, we develop scenarios of future glacier change in the Everest region of Nepal. Glaciers in the region are concentrated at elevations between 5000 and 6000 m, and we expect them to be highly sensitive to increased temperatures. Using a range of climate models and emission scenarios, our model indicates potential glacier volume decreases of between -73% and -96% by the year 2100.
Brief Communication: Sudden drainage of a subglacial lake beneath the Greenland Ice Sheet
Summary: In the summer of 2011, a large crater appeared in the surface of the Greenland Ice Sheet. It formed when a subglacial lake, equivalent to 10,000 swimming pools, catastrophically drained in less than 14 days. This is the first direct evidence that surface meltwater that drains through cracks to the bed of the ice sheet can build up in subglacial lakes over long periods of time. The sudden drainage may have been due to more surface melting and an increase in meltwater reaching the bed.
Paleo-ice flow directions of the Northern Antarctic Peninsula ice sheet based upon a new synthesis of seabed imagery
C. Lavoie, E. W. Domack, E. C. Pettit, T. A. Scambos, R. D. Larter, H.-W. Schenke, K. C. Yoo, J. Gutt, J. Wellner, M. Canals, J. B. Anderson, and D. Amblas The Cryosphere Discuss., 8, 5321-5360, 2014 AbstractDiscussion Paper (PDF, 4276 KB)Supplement (254691 KB)Interactive Discussion (Open, 2 Comments)Manuscript under review for TC
15 Oct 2014
Assessment of permafrost distribution maps in the Hindu Kush–Himalayan region using rock glaciers mapped in Google Earth
The melt pond fraction and spectral sea ice albedo retrieval from MERIS data: validation and trends of sea ice albedo and melt pond fraction in the Arctic for years 2002–2011
L. Istomina, G. Heygster, M. Huntemann, P. Schwarz, G. Birnbaum, R. Scharien, C. Polashenski, D. Perovich, E. Zege, A. Malinka, A. Prikhach, and I. Katsev The Cryosphere Discuss., 8, 5227-5292, 2014 AbstractDiscussion Paper (PDF, 11870 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for TC
15 Oct 2014
Tracing glacial disintegration from the LIA to the present using a LIDAR-based hi-res glacier inventory
Summary: In this study, a new Austrian glacier inventory has been compiled to monitor the current glacial disintegration. To expand the time series of digital glacier inventories in the past, the glacier inventory of the Little Ice Age has been updated. The long time series of homogeneous inventories allows tackling the complexity of the reaction of specific glaciers to the common climate change signal.
Excess heat in 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 as 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 Discuss., 8, 5169-5193, 2014 AbstractDiscussion Paper (PDF, 1132 KB)Interactive Discussion (Open, 3 Comments)Manuscript under review for TC
13 Oct 2014
Geophysical mapping of palsa peatland permafrost
Summary: Permafrost peatlands are hydrological and biogeochemical hotspots in discontinuous permafrost areas. We estimate the depths to the permafrost table surface and base across a peatland in northern Sweden, using ground penetrating radar and electrical resistivity tomography. Seasonal frost tables, taliks, and the permafrost base could be detected. The results highlight the added value of combining techniques for assessing distributions of permafrost in the rapidly changing sporadic permafrost zone.
On producing sea ice deformation dataset from SAR-derived sea ice motion
Summary: We present a new method to compute sea ice deformation fields from satellite-derived motion. The method particularly reduces the artificial noise that arises along discontinuities in the sea ice motion field. We estimate that this artificial noise may cause an overestimation of about 60% of sea ice opening and closing. The constant overestimation of the opening and closing could have led in previous studies to a large overestimation of freezing in leads, salt rejection and sea ice ridging.
Measurements of light absorbing particulates on the glaciers in the Cordillera Blanca, Peru
Summary: This paper presents the results of three 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 2 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 Discuss., 8, 5077-5103, 2014 AbstractDiscussion Paper (PDF, 2443 KB)Interactive Discussion (Open, 2 Comments)Manuscript under review for TC
08 Oct 2014
Black carbon in snow in the upper Himalayan Khumbu Valley, Nepal: observations and modeling of the impact on snow albedo, melting, and radiative forcing
Site-level model intercomparison of high latitude and high altitude soil thermal dynamics in tundra and barren landscapes
A. Ekici, S. Chadburn, N. Chaudhary, L. H. Hajdu, A. Marmy, S. Peng, J. Boike, E. Burke, A. D. Friend, C. Hauck, G. Krinner, M. Langer, P. A. Miller, and C. Beer The Cryosphere Discuss., 8, 4959-5013, 2014 AbstractDiscussion Paper (PDF, 11047 KB)Interactive Discussion (Open, 1 Comment)Manuscript under review for TC
18 Sep 2014
Snow cover reconstruction methodology based on historic in situ observations and recent remote sensing data
A. Gafurov, S. Vorogushyn, A. Merkushkin, D. Duethmann, D. Farinotti, and B. Merz The Cryosphere Discuss., 8, 4645-4680, 2014 AbstractDiscussion Paper (PDF, 4036 KB)Interactive Discussion (Open, 4 Comments)Manuscript under review for TC
01 Sep 2014
A conceptual model of cyclical glacier flow in overdeepenings
Wintertime storage of water in buried supraglacial lakes across the Greenland Ice Sheet
L. S. Koenig, D. J. Lampkin, L. N. Montgomery, S. L. Hamilton, J. B. Turrin, C. A. Joseph, S. E. Moutsafa, B. Panzer, K. A. Casey, J. D. Paden, C. Leuschen, and P. Gogineni The Cryosphere Discuss., 8, 3999-4031, 2014 AbstractDiscussion Paper (PDF, 1897 KB)Interactive Discussion (Open, 2 Comments)Manuscript under review for TC
18 Jul 2014
Future permafrost conditions along environmental gradients in Zackenberg, Greenland
S. Westermann, B. Elberling, S. Højlund Pedersen, M. Stendel, B. U. Hansen, and G. E. Liston The Cryosphere Discuss., 8, 3907-3948, 2014 AbstractDiscussion Paper (PDF, 805 KB)Interactive Discussion (Open, 1 Comment)Manuscript under review for TC
16 Jul 2014
Modelled present and future thaw lake area expansion/contraction trends throughout the continuous permafrost zone