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Christina E. Rosanova

Publications and source records attributed to Christina E. Rosanova.

4 recordsLinked to original sources
USGS2017

Retreat of northern margins of George VI and Wilkins Ice Shelves, Antarctic Peninsula

The George VI and Wilkins Ice Shelves are considered at risk of disintegration due to a regional atmospheric warming trend on the Antarctic Peninsula. Retreat of the northern margin of the George VI Ice Shelf has been observed previously, but the Wilkins Ice Shelf was thought to be stable. We investigated the positions of the northern fronts of these shelves from the literature and looked for changes on 1974 Landsat and 1992 and 1995 European remote-sensing satellite (ERS) synthetic aperture radar images. Our investigation shows that the northern George VI Ice Shelf lost a total of 906 km2 between 1974 and 1992, and an additional 87 km2 by 1995. The northern margin of the Wilkins Ice Shelf lost 796 km2 between 1990 and 1992, and another 564 km2 between 1992 and 1995. Armadas of tabular icebergs were visible in front of this shelf in the ERS images. These two ice shelves mark the southernmost documented conspicuous retreat of ice-shelf margins.

George VI Ice Shelf, Wilkins Ice Shelf↗
USGS2017

Velocities of the Pine Island, Thwaites, and smaller glaciers along the Marie Byrd Land coast, West Antarctica

Average velocities for time intervals ranging from < 1 to 15 years were measured by tracking ice-surface patterns on sequential Landsat and European Remote-sensing Satellite synthetic aperture radar images. Velocities ofThwaites Glacier range from 2.2 km a −1 above the grounding line to 3.4 km a −1 at the limit of measurements onThwaites Glacier ice tongue. The glacier increases in velocity by about 1 km a −1 where it crosses the grounding line. Over the period 1984-93, Thwaites Glacier ice tongue accelerated by about 0.6 kin a .Velocities of the floating part of several minor glaciers and some ice shelves are also determined: Land Glacier, 17—1.9 km a −1 ; DeVicq Glacier, 0.7-1.1 km a −1 ; Dotson Ice Shelf 0.2-0.5 km a −1 ; Gctz Ice Shelf, 0.2-0.8 km a −1 ; and Sulzberger Ice Shelf, 0.01 -0.02 km a −1 . The high velocities along the Marie Byrd Land coast are consistent with the high precipitation rates over West Antarctica and, for some of the glaciers, the lack of buttressing ice shelves.

Annals of Glaciology↗
USGS2017

Velocities and mass balance of Pine Island Glacier, West Antarctica, derived from ERS-1 SAR images

Pine Island Glacier is one of the major ice streams draining West Antarctica. We calculated average velocities for both its grounded and floating parts by tracking crevasses and other patterns moving with the ice on two sequential images acquired in February and December 1992 by ERS-1 SAR (European Remote-Sensing Satellite, Synthetic Aperture Radar). Velocities in the fast-moving central parts of the glacier range from about 1.3 km a −1 on the grounded part to about 2.6 km a −1 on the floating part. Velocity increases rapidly just below the grounding line. For the floating part, velocities are approximately 0.3 km a −1 faster than previously established from Landsat images by other workers. This observation suggests that the discharge is larger and, therefore, the mass balance less positive than previously thought; however, our study also shows that current information is insufficient to allow for precise mass-balance calculations. Images of the glacier front show that a calving event released an iceberg about 5 km wide between February and December 1992. The position of the glacier front has not changed substantially between 1973 (Landsat image) and 1992 (ERS-1 images).

Pine Island Glacier↗