|
Accession Number
|
N20120010371
|
|
Title
|
Variability of Basal Melt Beneath the Pine Island Glacier Ice Shelf, West Antarctica.
|
|
Publication Date
|
Sep 2011
|
|
Media Count
|
15p
|
|
Personal Author
|
D. G. Vaughan P. Vornberger R. Bindschadler
|
|
Abstract
|
Observations from satellite and airborne platforms are combined with model calculations to infer the nature and efficiency of basal melting of the Pine Island Glacier ice shelf, West Antarctica, by ocean waters. Satellite imagery shows surface features that suggest ice-shelf-wide changes to the ocean s influence on the ice shelf as the grounding line retreated. Longitudinal profiles of ice surface and bottom elevations are analyzed to reveal a spatially dependent pattern of basal melt with an annual melt flux of 40.5 Gt/a. One profile captures a persistent set of surface waves that correlates with quasi-annual variations of atmospheric forcing of Amundsen Sea circulation patterns, establishing a direct connection between atmospheric variability and sub-ice-shelf melting. Ice surface troughs are hydrostatically compensated by ice-bottom voids up to 150m deep. Voids form dynamically at the grounding line, triggered by enhanced melting when warmer-than-average water arrives. Subsequent enlargement of the voids is thermally inefficient (4% or less) compared with an overall melting efficiency beneath the ice shelf of 22%. Residual warm water is believed to cause three persistent polynyas at the ice-shelf front seen in Landsat imagery. Landsat thermal imagery confirms the occurrence of warm water at the same locations.
|
|
Keywords
|
Basalt
Glaciers
Land ice
Landsat satellites
Melting
Position(Location)
Satellite imagery
Surface waves
Troughs
Voids
|
|
|
Source Agency
|
National Aeronautics and Space Administration
|
|
NTIS Subject Category
|
55A - Aeronomy
|
|
Corporate Author
|
Goddard Space Flight Center, Greenbelt, MD.
|
|
Document Type
|
Journal article
|
|
Title Note
|
N/A
|
|
NTIS Issue Number
|
1226
|
|
Contract Number
|
N/A
|
