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dc.date.accessioned2013-03-12T09:01:42Z
dc.date.available2013-03-12T09:01:42Z
dc.date.issued2011en_US
dc.date.submitted2011-06-17en_US
dc.identifier.citationMüller, Karsten. Microwave penetration in polar snow and ice: Implications for GPR and SAR. Doktoravhandling, University of Oslo, 2011en_US
dc.identifier.urihttp://hdl.handle.net/10852/12329
dc.description.abstractThe state of the continental ice masses has a direct impact on the global sea level. Changes in the polar regions will not only impact the people living in the Arctic, but also people living along coastlines around the world. Monitoring the current and future state of the global ice masses is therefore of greatest interest. Microwave remote sensing of the cryosphere from ground, air or space is an active and fast developing field of research. In this thesis we investigate the interaction of microwaves with snow and ice by means of ground penetrating radar (GPR) and relate the findings to observations from space-borne radars (SAR or InSAR). We applied GPR to extend the 200 year mean surface mass balance (SMB) measurement from firn cores in a previously unmapped part of East Antarctica. Our findings show up to 50% lower values than estimated from modelling or remote sensing. However, our evaluated time period is much longer and our spatial resolution much finer. We relate our SMB values to radar backscatter from space-borne radar and use this correlation to further extend the SMB estimate over a 76000 km2 large area on the East Antarctic plateau. We investigate the position of the GPR phase center (zö) in snow, firn and ice in the interior and exterior of the East Antarctic Plateau and a glacier on Svalbard. Values of zö exceed 40 m in the dry firn of the East Antarctic Plateau at frequencies of 1.75 GHz. Thus, we have to expect a potential bias when measuring topography by means of InSAR in these areas. In coastal Antarctica and on an Arctic glacier zö often exceeds 5 m even at C-band. Consequently, deriving mass-balance estimates through monitoring elevation changes with radar are difficult to interpret. However, we find that zö aligns with the previous summer surface in the ablation zone of the glacier for S- and C-band frequencies. Thus, in this part of the glacier elevation changes can be monitored with InSAR. We attribute the difference in zö from the ablation zone to the firn zone of the glacier to a change in scattering mechanisms, which results in stronger radar backscatter from the firn zone. We use this difference to map the extent of the firn area by a simple threshold classification.eng
dc.language.isoengen_US
dc.relation.haspartPaper I / Chapter 5 An 860-km surface mass balance profile on the East Antarctic Plateau derived by GPR. Karsten Müller, Anna Sinisalo, Helgard Ansch¨utz, Svein-Erik Hamran, Jon-Ove Hagen, Joseph R. McConnell, and Daniel R. Pasteris Annals of Glaciology, 51(55), 1-8. http://dx.doi.org/10.3189/172756410791392718
dc.relation.haspartPaper II / Chapter 6 Phase-center of L-band radar in polar snow and ice. Karsten Müller, Svein-Erik Hamran, Anna Sinisalo, and Jon-Ove Hagen IEEE Transactions on Geoscience and Remote Sensing, Early Access 31 May 2011. (c) 2011 IEEE. Personal use of this material is permitted. http://dx.doi.org/10.1109/TGRS.2011.2140376
dc.relation.haspartPaper III / Chapter 7 Change in microwave scattering mechanisms along Kongsvegen glacier, Svalbard and implications for SAR monitoring. Karsten Müller, Svein-Erik Hamran, Anna Sinisalo, and Jon-Ove Hagen In prep. The paper is removed from the thesis in DUO.
dc.relation.urihttp://dx.doi.org/10.3189/172756410791392718
dc.relation.urihttp://dx.doi.org/10.1109/TGRS.2011.2140376
dc.titleMicrowave penetration in polar snow and ice: Implications for GPR and SARen_US
dc.typeDoctoral thesisen_US
dc.date.updated2012-09-17en_US
dc.creator.authorMüller, Karstenen_US
dc.subject.nsiVDP::450en_US
cristin.unitcode152200en_US
cristin.unitnameGeofagen_US
dc.identifier.bibliographiccitationinfo:ofi/fmt:kev:mtx:ctx&ctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft.au=Müller, Karsten&rft.title=Microwave penetration in polar snow and ice: Implications for GPR and SAR&rft.inst=University of Oslo&rft.date=2011&rft.degree=Doktoravhandlingen_US
dc.identifier.urnURN:NBN:no-29265en_US
dc.type.documentDoktoravhandlingen_US
dc.identifier.duo129655en_US
dc.contributor.supervisorSvein-Erik Hamran, Jon-Ove Hagenen_US
dc.identifier.bibsys120457598en_US
dc.identifier.fulltextFulltext https://www.duo.uio.no/bitstream/handle/10852/12329/2/dravhandling-muller.pdf


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