glaciers
An optimal estimation method for simultaneously determining both basal slipperiness and basal topography from variations in surface flow velocity and topography along a flow line on ice streams and ice sheets is presented. The authors use Bayesian inference to update prior statistical estimates for basal topography and slipperiness using surface measurements along a...
The Taku Glacier, Alaska has advanced 7.5 km since the late nineteenth century, while all other primary outlet glaciers of the Juneau Icefield are in retreat. The Juneau Icefield Research Program has completed field work on the Taku Glacier annually since 1946. The collected observations of surface mass balance, glacier velocity and glacier thickness at Profile IV 29...
A Landsat Thematic Mapper (TM) scene from 2003 covering the Jotunheimen and Breheimen region has been used to map the recent glacier extents using thresholded ratio images (TM3/TM5). Orthoprojected aerial photographs and glacier outlines from digital maps have been used to validate the method and control the results. The authors further calculated glacier changes by...
Volume loss of valley glaciers is now considered to be a significant contribution to sea level rise. Understanding and identifying the processes involved in accelerated mass loss are necessary to determine their impact on the global system. Here the authors present results from a series of model experiments with a higher-order thermomechanically coupled flowline model (Pattyn...
North Cascade glacier annual balance measured on 10 glaciers from 1984-2006 yielded mean annual balance (ba) of -0.54 m/a, and -12.38 m cumulatively. This is a significant loss for glaciers that average 30-60 m in thickness, 20-40% of their entire volume. Two observed glaciers, Lewis Glacier and Spider Glacier, no longer exist. The ba of North Cascade glaciers is reliably...
The authors compare five years of meteorological records from automatic weather stations (AWSs) on Storbreen and Midtdalsbreen, two glaciers in southern Norway, located approximately 120 km apart. The records are obtained from identical AWSs with an altitude difference of 120 m and cover the period September 2001 to September 2006. Air temperature at the AWS locations is...
In this study the authors consider contrasting continental (Orulgan, Suntar-Khayata and Chersky ranges located in the Pole of Cold area at the contact of Atlantic and Pacific influences) and maritime (Kamchatka under the Pacific influence) Russian glacier systems. Their purpose is to present a simple method for the projection of change of the main parameters of these glacier...
The authors present velocity observations of a glacier outlet in Vatnajökull, Iceland, deduced from interferometric SAR (InSAR) data obtained during the ERS1/2 tandem mission in 1995–2000. More than a 50% decrease in glacier velocity was observed subsequent to a large jökulhlaup from the subglacial lake Grímsvötn in 1996. The glacier had not...
This study provides mapping and analysis of the maximum glacier extent during the "Little Ice Age" in Jotunheimen, Southern Norway, on a regional scale. Remote sensing techniques were used to map the glacier area at the maximum of the "Little Ice Age" (mid 18th century AD). For validation of the mapping, interpretation of existing glaciochronological...
A large number of Himalayan glacier catchments are under the influence of humid climate with snowfall in winter (November-April) and South-West monsoon in summer (June–September) dominating the regional hydrology. Such catchments are defined as "Himalayan catchment", where the glacier melt water contributes to the river flow during the period of annual high...
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