Deglaciation of the Caucasus Mountains, Russia/Georgia, in the 21st century observed with ASTER satellite imagery and aerial photography
Summary: The paper investigates changes in the area of 498 glaciers in the main Caucasus ridge and on Mt. Elbrus (the highest summit in geographical Europe), Russia/Georgia in the late 20th and 21st centuries using ASTER and Landsat imagery with 15 m resolution from 1999-2001 and 2010-2012 and aerial photography from 1987-2001. The glacier area decreased by 4.7±2.1% or 19.2±8.7 km2 from 1999-2001 to 2010/12. The recession rates of glacier terminus more than doubled between 1987-2000/01 and 2000/01–2010.
Are seasonal calving dynamics forced by buttressing from ice mélange or undercutting by melting? Outcomes from full-Stokes simulations of Store Glacier, West Greenland
Summary: Many iceberg-calving glaciers in Greenland have recently been observed to accelerate and retreat, prompting fears about their future stability in the face of climate change. We present results from a flow modelling study of Store Glacier, West Greenland, which suggest that glacier geometry may play an important role in determining calving glacier stability. Store Glacier flows into a narrow, shallow fjord and our model suggests this may make it insensitive to future ocean warming.
Inferred basal friction and surface mass balance of the Northeast Greenland Ice Stream using data assimilation of ICESat (Ice Cloud and land Elevation Satellite) surface altimetry and ISSM (Ice Sheet System Model)
Summary: We present a temporal inversion of surface mass balance and basal friction for the Northeast Greenland Ice Sheet between 2003 and 2009, using the altimetry record from ICESat. The inversion relies on automatic differentiation of ISSM and demonstrates the feasibility of assimilating altimetry records into reconstructions of the Greenland Ice Sheet. The boundary conditions provide a snapshot of the state of the ice for this period and can be used for further process studies.
Estimating the volume of glaciers in the Himalayan–Karakoram region using different methods
Summary: Existing methods (area–volume relations, a slope-dependent volume estimation method, and two ice-thickness distribution models) are used to estimate the ice reserves stored in Himalayan–Karakoram glaciers. Resulting volumes range from 2955–4737km³. Results from the ice-thickness distribution models agree well with local measurements; volume estimates from area-related relations exceed the estimates from the other approaches. Evidence on the effect of the selected method on results is provided.
H. Frey, H. Machguth, M. Huss, C. Huggel, S. Bajracharya, T. Bolch, A. Kulkarni, A. Linsbauer, N. Salzmann, and M. Stoffel The Cryosphere, 8, 2313-2333, 2014 AbstractFinal Revised Paper (PDF, 7532 KB)Discussion Paper (TCD)
12 Dec 2014
Assessing spatio-temporal variability and trends in modelled and measured Greenland Ice Sheet albedo (2000–2013)
Glacier topography and elevation changes derived from Pléiades sub-meter stereo images
Summary: We evaluate the potential of Pléiades sub-meter satellite stereo imagery to derive digital elevation models (DEMs) of glaciers and their elevation changes. The vertical precision of the DEMs is ±1 m, even ±0.5m on the flat glacier tongues. Similar precision levels are obtained in accumulation areas. Comparison of a Pléiades DEM with a SPOT5 DEM reveals the strongly negative region-wide mass balances of glaciers in the Mont Blanc area (-1.04±0.23m at 1 water equivalent) during 2003-2012.
E. Berthier, C. Vincent, E. Magnússon, Á. Þ. Gunnlaugsson, P. Pitte, E. Le Meur, M. Masiokas, L. Ruiz, F. Pálsson, J. M. C. Belart, and P. Wagnon The Cryosphere, 8, 2275-2291, 2014 AbstractFinal Revised Paper (PDF, 8151 KB)Discussion Paper (TCD)
10 Dec 2014
Study of a temperature gradient metamorphism of snow from 3-D images: time evolution of microstructures, physical properties and their associated anisotropy
Post-LIA glacier changes along a latitudinal transect in the Central Italian Alps
Summary: A post-LIA multitemporal glacier inventory along a latitudinal transect in the Central Italian Alps shows that average annual decrease (AAD) in glacier area has risen by about ten times from 1860--1990 to 1990--2007. When considering glaciers smaller than 0.5 km2, post-1990 AAD follows the latitudinal gradient with maritime-like Orobie glaciers shrinking much less than Disgrazia and Livigno glaciers. We argue that the recent resilience of glaciers in Orobie is due to local climatic decoupling.
Processes governing the mass balance of Chhota Shigri Glacier (western Himalaya, India) assessed by point-scale surface energy balance measurements
Summary: This paper presents point-scale surface energy balance on Chhota Shigri Glacier, Western Himalaya, India. Energy is available for melting only in summer-monsoon. Net all-wave radiation is the main heat flux towards the glacier surface accounting for 80% of the total melting energy followed by sensible (13%), latent (5%) turbulent and conductive (2%) heat fluxes. The intensity of summer-monsoon snowfalls is found among the most important drivers controlling the mass balance of this glacier.
Detailed ice loss pattern in the northern Antarctic Peninsula: widespread decline driven by ice front retreats
Summary: This study of one of the most rapidly changing glacier regions on earth -- the Antarctic Peninsula -- uses two types of satellite data to measure the rates of ice loss in detail for the individual glaciers. The satellite data is laser altimetry from ICESat and stereo image DEM differences. The results show that 24..9 ± 7.8 billion tons of ice are lost from the region north of 66°S on the peninsula each year. The majority of the data cover 2003-2008.
Sensitivity of the Weddell Sea sector ice streams to sub-shelf melting and surface accumulation
A. P. Wright, A. M. Le Brocq, S. L. Cornford, R. G. Bingham, H. F. J. Corr, F. Ferraccioli, T. A. Jordan, A. J. Payne, D. M. Rippin, N. Ross, and M. J. Siegert The Cryosphere, 8, 2119-2134, 2014 AbstractFinal Revised Paper (PDF, 6027 KB)Discussion Paper (TCD)
24 Nov 2014
Combining damage and fracture mechanics to model calving
Snowmelt onset over Arctic sea ice from passive microwave satellite data: 1979–2012
Summary: A new version of the Snow Melt Onset Over Arctic Sea Ice from SMMR and SSM/I-SSMIS Brightness Temperatures is now available. From this data set, a statistical summary of melt onset (MO) dates on Arctic sea ice is presented. Significant trends indicate that MO is occurring 6.6days/decade earlier in the year for the Arctic while regional trends in MO are as great as 11.8days/decade earlier in the East Siberian Sea. The Bering Sea is an outlier where MO is occurring 3.1days/decade later.