The Cryosphere The imbalance of glaciers after disintegration of Larsen-B ice shelf, Antarctic Peninsula
Abstract. The outlet glaciers to the embayment of the Larsen-B Ice Shelf started to accelerate soon after the ice shelf disintegrated in March 2002. We analyse high resolu-tion radar images of the TerraSAR-X satellite, launched in June 2007, to map the motion of outlet glaciers in detail. The fronta...
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| Format: | Text |
| Language: | English |
| Published: |
2011
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1032.7568 http://www.the-cryosphere.net/5/125/2011/tc-5-125-2011.pdf |
| Summary: | Abstract. The outlet glaciers to the embayment of the Larsen-B Ice Shelf started to accelerate soon after the ice shelf disintegrated in March 2002. We analyse high resolu-tion radar images of the TerraSAR-X satellite, launched in June 2007, to map the motion of outlet glaciers in detail. The frontal velocities are used to estimate the calving fluxes for 2008/2009. As reference for pre-collapse conditions, when the glaciers were in balanced state, the ice fluxes through the same gates are computed using ice motion maps derived from interferometric data of the ERS-1/ERS-2 satellites in 1995 and 1999. Profiles of satellite laser altimetry from ICESat, crossing the terminus of several glaciers, indicate considerable glacier thinning between 2003 and 2007/2008. This is taken into account for defining the calving cross sec-tions. The difference between the pre- and post-collapse fluxes provides an estimate on the mass imbalance. For the Larsen-B embayment the 2008 mass deficit is estimated at 4.34 ± 1.64 Gt a−1, significantly lower than previously pub-lished values. The ice flow acceleration follows a similar pattern on the various glaciers, gradually decreasing in mag-nitude with distance upstream from the calving front. This suggests stress perturbation at the glacier front being the main factor for acceleration. So far there are no signs of slow-down indicating that dynamic thinning and frontal re-treat will go on. 1 |
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