World Library  


Add to Book Shelf
Flag as Inappropriate
Email this Book

Seabed Topography Beneath Larsen C Ice Shelf from Seismic Soundings : Volume 7, Issue 4 (15/08/2013)

By Brisbourne, A. M.

Click here to view

Book Id: WPLBN0004022901
Format Type: PDF Article :
File Size: Pages 30
Reproduction Date: 2015

Title: Seabed Topography Beneath Larsen C Ice Shelf from Seismic Soundings : Volume 7, Issue 4 (15/08/2013)  
Author: Brisbourne, A. M.
Volume: Vol. 7, Issue 4
Language: English
Subject: Science, Cryosphere, Discussions
Collections: Periodicals: Journal and Magazine Collection, Copernicus GmbH
Historic
Publication Date:
2013
Publisher: Copernicus Gmbh, Göttingen, Germany
Member Page: Copernicus Publications

Citation

APA MLA Chicago

Nicholls, K. W., King, E. C., Smith, A. M., Makinson, K., Brisbourne, A. M., & Holland, P. R. (2013). Seabed Topography Beneath Larsen C Ice Shelf from Seismic Soundings : Volume 7, Issue 4 (15/08/2013). Retrieved from http://nook-library.net/


Description
Description: British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, UK. Seismic reflection soundings of ice thickness and seabed depth were acquired on the Larsen C Ice Shelf in order to test a sub-shelf bathymetry model derived from the inversion of IceBridge gravity data. A series of lines were collected, from the Churchill Peninsula in the north to the Joerg Peninsula in the south, and also towards the ice front. Sites were selected using the bathymetry model derived from the inversion of free-air gravity data to indicate key regions where sub-shelf oceanic circulation may be affected by ice draft and sub-shelf cavity thickness. The seismic velocity profile in the upper 100 m of firn and ice was derived from shallow refraction surveys at a number of locations. Measured temperatures within the ice column and at the ice base were used to define the velocity profile through the remainder of the ice column. Seismic velocities in the water column were derived from previous in situ measurements. Uncertainties in ice and water cavity thickness are in general <10 m. Compared with the seismic measurements, the root-mean-square error in the gravimetrically derived bathymetry at the seismic sites is 162 m. The seismic profiles prove the non-existence of several bathymetric features that are indicated in the gravity inversion model, significantly modifying the expected oceanic circulation beneath the ice shelf. Similar features have previously been shown to be highly significant in affecting basal melt rates predicted by ocean models. The discrepancies between the gravity inversion results and the seismic bathymetry are attributed to the assumption of uniform geology inherent in the gravity inversion process and also the sparsity of IceBridge flight lines. Results indicate that care must be taken when using bathymetry models derived by the inversion of free-air gravity anomalies. The bathymetry results presented here will be used to improve existing sub-shelf ocean circulation models.

Summary
Seabed topography beneath Larsen C Ice Shelf from seismic soundings

Excerpt
Kohnen, H.: Über die Beziehung zwischen seismischen Geschwindigkeiten und der Dichte in Firn und Eis, Zeitschrift fur Geophysik, 38, 925–935, 1972.; Kirchner, J. F. and Bentley, C. R.: RIGGS III: seismic short-refraction studies using an analytical curve-fitting technique, Antar. Res. S., 42, 109–126, 1990.; Cook, A. J. and Vaughan, D. G.: Overview of areal changes of the ice shelves on the Antarctic Peninsula over the past 50 years, The Cryosphere, 4, 77–98, doi:10.5194/tc-4-77-2010, 2010.; Determann, J., Thyssen, F., and Engelhardt, H.: Ice thickness and sea depth derived from reflection-seismic measurements on the central part of Filchner-Ronne Ice Shelf, Antarctica, Ann. Glaciol., 11, 14–18, 1988.; Fahnestock, M. A., Abdalati, W., and Shuman, C. A.: Long melt seasons on ice shelves of the Antarctic Peninsula: an analysis using satellite-based microwave emission measurements, Ann. Glaciol., 34, 127–133, 2002.; Fahrbach, E., Peterson, R., Rohardt, G., Schlosser, P., and Bayer, R.: Suppression of bottom water formation in the southeastern Weddell Sea, Deep-Sea Res. Pt. I, 41, 389–411, 1994.; Forste, C., Schmidt, R., Stubenvoll, R., Flechtner, F., Meyer, U., Konig, R., Neumayer, H., Biancale, R., Lemoine, J. M., Bruinsma, S., Loyer, S., Barthelmes, F., and Esselborn, S.: The GeoForschungsZentrum Potsdam/Groupe de Recherche de Geodesie Spatiale satellite-only and combined gravity field models: EIGEN-GL04S1 and EIGEN-GL04C, J. Geodesy, 82, 331–346, doi:10.1007/s00190-007-0183-8, 2008.; Fricker, H. A. and Padman, L.: Thirty years of elevation change on Antarctic Peninsula ice shelves from multimission satellite radar altimetry, J. Geophys. Res.-Oceans, 117, C02026, doi:10.1029/2011jc007126, 2012.; Galton-Fenzi, B. K., Maraldi, C., Coleman, R., and Hunter, J.: The cavity under the Amery Ice Shelf, East Antarctica, J. Glaciol., 54, 881–887, 2008.; King, E. C., Jarvis, E. P., and Mowse, E. A.: Seismic characteristics of an airgun fired over snow, Cold Reg. Sci. Tech., 21, 201–207, 1993.; Bart, P. J. and Anderson, J. B.: Seismic record of glacial events affecting the Pacific margin of the northwestern Antarctic Peninsula, Ant. Res. Series, 68, 75–95, 1995.; Booth, A. D., Kulessa, B., King, E. C., Clark, R. A., Jansen, D., Sammonds, P., and Luckman, A.: Physical properties of meteoric and marine ice in Larsen C Ice Shelf, Antarctic Peninsula, from Q and AVA Analyses of Reflection Seismic Data, EGU General Assembly, Vienna, Austria, 2010, EGU2013-6531, 2013.; Cochran, J. R. and Bell, R. E.: Inversion of IceBridge gravity data for continental shelf bathymetry beneath the Larsen Ice Shelf, Antarctica, J. Glaciol., 58, 540–552, 2012.; Craven, M., Allison, I., Fricker, H. A., and Warner, R.: Properties of a marine ice layer under the Amery Ice Shelf, East Antarctica, J. Glaciol., 55, 717–728, 2009.; Glasser, N. F. and Scambos, T. A.: A structural glaciological analysis of the 2002 Larsen B ice-shelf collapse, J. Glaciol., 54, 3–16, doi:10.3189/002214308784409017, 2008.; Griggs, J. A. and Bamber, J. L.: Ice shelf thickness over Larsen C, Antarctica, derived from satellite altimetry, Geophys. Res. Lett., 36, L19501, doi:10.1029/2009gl039527, 2009.; Grosfeld, K., Gerdes, R., and Determann, J.: Thermohaline circulation and interaction between ice shelf cavities and the adjacent open ocean, J. Geophys. Res.-Oceans, 102, 15595–15610, doi:10.1029/97jc00891, 1997.; Haran, T., Bohlander, J., Scambos, T., Fahnestock, M., and compilers: MODIS Mosaic of Antarctica (MOA) Image Map, Digital Media, National Snow and Ice Data Center, Boulder, CO, USA, 2005.; Hemer, M. A., Hun

 

Click To View

Additional Books


  • A New Model for Quantifying Subsurface I... (by )
  • Testing Hypotheses of the Cause of Perip... (by )
  • Comparing Ice Discharge Through West Ant... (by )
  • Climatic Drivers of Seasonal Glacier Mas... (by )
  • Sea Ice and the Ocean Mixed Layer Over t... (by )
  • The Effect of Changing Sea Ice on the Vu... (by )
  • Comparison of Airborne Radar Altimeter a... (by )
  • An Improved Cryosat-2 Sea Ice Freeboard ... (by )
  • A Multi-parameter Hydrochemical Characte... (by )
  • Thermal Structure and Basal Sliding Para... (by )
  • Smos Derived Sea Ice Thickness: Algorith... (by )
  • Uncertainty in Future Solid Ice Discharg... (by )
Scroll Left
Scroll Right

 



Copyright © World Library Foundation. All rights reserved. eBooks from Nook eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.