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The Cryosphere An interactive open-access journal of the European Geosciences Union
https://doi.org/10.5194/tcd-9-3995-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
30 Jul 2015
Review status
This discussion paper is a preprint. A revision of the manuscript for further review has not been submitted.
Subglacial hydrology indicates a major shift in dynamics of the West Antarctic Ross Ice Streams within the next two centuries
S. Goeller, V. Helm, M. Thoma, and K. Grosfeld Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
Abstract. The mass export of the West Antarctic Ice Sheet (WAIS) is dominated by fast flowing ice streams. Understanding their dynamics is a key to estimate the future integrity of the WAIS and its contributions to global sea level rise. This study focuses on the Ross Ice Streams (RIS) at the Siple Coast. In this sector, observations reveal a high variability of ice stream pathways and velocities which is assumed to be driven by subglacial hydrology. We compute subglacial water pathways for the present-day ice sheet and verify this assumption by finding high correlations between areas of enhanced basal water flow and the locations of the RIS. Moreover, we reveal that the ice flow velocities of the individual ice streams are correlated with the sizes of the water catchment areas draining underneath. The future development of the subglacial hydraulic environment is estimated by applying ice surface elevation change rates observed by ICESat and CryoSat-2 to the present-day ice sheet geometry and thus assessing prognostic basal pressure conditions. Our simulations consistently indicate that a major hydraulic tributary of the Kamb and Whillans Ice Stream (KIS and WIS) will be redirected underneath the Bindschadler Ice Stream (BIS) within the next two centuries. The water catchment area feeding underneath the BIS is estimated to grow by about 50 % while the lower part of the stagnated KIS becomes increasingly separated from its upper hydraulic tributaries. We conclude, that this might be a continuation of the subglacial hydraulic processes which caused the past stagnation of the KIS. The simulated hydraulic rerouting is also capable to explain the observed deceleration of the WIS and indicates a possible future acceleration of the BIS accompanied by an increased ice drainage of the corresponding ice sheet interior.

Citation: Goeller, S., Helm, V., Thoma, M., and Grosfeld, K.: Subglacial hydrology indicates a major shift in dynamics of the West Antarctic Ross Ice Streams within the next two centuries, The Cryosphere Discuss., https://doi.org/10.5194/tcd-9-3995-2015, in review, 2015.
S. Goeller et al.
Interactive discussionStatus: closed (peer review stopped)
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
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RC C1479: 'Referee Comment', Anonymous Referee #1, 25 Aug 2015 Printer-friendly Version 
AC C2792: 'Response to anonymous reviewer #1', Sebastian Goeller, 15 Jan 2016 Printer-friendly Version Supplement 
 
RC C1978: 'Goeller et al. - Reviewer 2', Anonymous Referee #2, 27 Oct 2015 Printer-friendly Version 
AC C2793: 'Response to anonymous reviewer #2', Sebastian Goeller, 15 Jan 2016 Printer-friendly Version Supplement 
S. Goeller et al.
S. Goeller et al.

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Short summary
The Ross Ice Streams in West Antarctica showed a high variability in the past. We model basal water pathways and catchment areas for present and future ice sheet geometries (gained by applying satellite-derived elevation change rates) in this sector. Thus, we can explain the current ice stream configuration and estimate implications for the next two centuries, where we find that a major basal hydraulic tributary of the Kamb and Whillans IS could be redirected underneath the Bindschadler IS.
The Ross Ice Streams in West Antarctica showed a high variability in the past. We model basal...
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