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Ice Shelf Elevation Changes due to Atmospheric Pressure Variations

Lookup NU author(s): Professor Matt King


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Floating ice shelves undergo vertical motion as a result of the response of the underlying ocean to changes in atmospheric pressure (Pair). This response is known as the inverse barometer effect (IBE). Open-ocean measurements of Pair and sea level agree with the theoretical response of 1 cm per millibar for low frequency variability of Pair. Here we demonstrate, using simultaneous records of Pair and GPS measurements of surface elevation (hIS) from several ice shelves, that shelves experience a response of similar magnitude. A simple correction for the IBE is justified for ice shelf response to low-frequency (omega <0.5 cycles per day) of Pair. At higher frequencies the IBE becomes weaker. The IBE contribution to hIS can exceed 50 cm, with typical magnitudes of 10-20 cm. Although the IBE is usually smaller than the tidal contribution to hIS, the tide can be removed with current Antarctic tide models with an accuracy similar to the IBE. Global atmospheric models, however, do not presently predict Pair with sufficient accuracy to be used to correct measured variability of hIS. Thus, in the absence of concurrent in situ Pair data, the IBE is a major source of error in correcting ice shelf heights for tasks such as deriving mean ice flow rates from SAR imagery, and measuring long-term trends in ice shelf height from satellite altimeters.

Publication metadata

Author(s): Padman L, King MA, Fricker HA

Publication type: Conference Proceedings (inc. Abstract)

Publication status: Published

Conference Name: Eos Transactions: Fall Meeting

Year of Conference: 2002

Pages: Abstract C51A-0936

Publisher: American Geophysical Union