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dc.contributor.advisorAnthony Paul, Doulgeris
dc.contributor.authorFors, Ane Schwenke
dc.date.accessioned2017-03-16T08:32:30Z
dc.date.available2017-03-16T08:32:30Z
dc.date.issued2017-03-17
dc.description.abstractIn this thesis, we explore the possibilities and limitations of using space-borne multi-polarimetric SAR in summer sea ice investigations. Both X and C-band data are examined. The study utilizes two data sets collected in the Arctic in 2011 (Fram Strait) and 2012 (north of Spitsbergen). Both sets combine satellite SAR scenes with co-located ground and air-borne measurements. Firstly, the study explores the summer sea ice type discrimination ability and temporal consistency of six polarimetric SAR features, and test an automatic segmentation algorithm based on the features. The algorithm succeed in segmenting the C-band SAR scenes into different sea ice types, but show poor performance in X-band. To develop the segmentation into a classification, labeling the segments, more information about how the polarimetric SAR features relate to sea ice properties is needed. The SAR signatures of two such properties, sea ice surface roughness and melt pond fraction, are therefore further investigated. Several C-band polarimetric SAR features are found related to sea ice macro-scale surface roughness in the study, but the relationships are sensitive to incidence angle, meteorological conditions, and changes in micro-scale surface roughness. The findings differ from previous studies in other seasons, demonstrating that SAR sea ice surface roughness signatures changes with season and sea ice type. Relationships between melt pond fraction and several X-band polarimetric SAR features are also demonstrated. Wind speed and SAR incidence angle are found to have a large impact on these results. The findings could imply a future potential of X-band melt pond fraction estimation with SAR, but this requires more advanced methods and an increased number of satellite scenes. Our study demonstrates new possibilities in segmentation and characterization of Arctic summer sea ice with multi-polarimetric satellite SAR. The findings contribute in the development of improved monitoring techniques for sea ice in a rapidly changing Arctic, increasing the safety of human activities and research in the ice-covered seas.en_US
dc.description.doctoraltypeph.d.en_US
dc.description.popularabstractArctic sea ice is changing with climate change. To better understand the observed changes, new and improved methods for monitoring of sea ice are required. This thesis explores possibilities and limitations in use of Synthetic Aperture Radar (SAR) for summer sea ice investigations. SAR transmits microwaves towards the sea ice, and registers the returned radiant energy; this information is used to construct images of the sea ice. This thesis compares SAR images with ground and helicopterborne measurements of sea ice. The work shows that SAR images of summer sea ice can be segmented into segments representing different sea ice types. Knowledge about how different sea ice properties influence SAR images is needed to identify the sea ice type of each segment. The study investigates how information about two such properties, sea ice surface roughness and melt pond fraction, influence SAR imagery. The results shows that high resolution SAR images and integration of meteorological data can increase the sea ice information gain during melt season.en_US
dc.description.sponsorshipProsjektet er finansiert av RDA Troms.en_US
dc.descriptionThe papers 2 and 3 of this thesis are not available in Munin. <br> Paper 2: Fors, A. S., Brekke, C., Gerland, S., Doulgeris, A. P., Beckers, J. F.: "Late Summer Arctic Sea Ice Surface Roughness Signatures in C-Band SAR Data". Available in <a href=http://dx.doi.org/10.1109/JSTARS.2015.2504384> IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing 2016, 9(3):1199-1215. </a> <br> Paper 3: Fors, A. S., Divine, D. V., Doulgeris, A. P., Renner, A. H. H., Gerland, S.: «Signature of Arctic first-year ice melt pond fraction in X-band SAR imagery”. (Manuscript).en_US
dc.identifier.isbn978-82-8236-254-2 (trykt) og 978-82-8236-255-9 (pdf)
dc.identifier.urihttp://hdl.handle.net/10037/10723
dc.language.isoengen_US
dc.publisherUiT Norges arktiske universiteten_US
dc.publisherUiT The Arctic University of Norwayen_US
dc.rights.accessRightsopenAccessen_US
dc.subject.courseIDDOKTOR-004
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Fysikk: 430en_US
dc.subjectVDP::Mathematics and natural science: 400::Physics: 430en_US
dc.titleInvestigations of summer sea ice with X and C-band multi-polarimetric synthetic aperture radar (SAR)en_US
dc.typeDoctoral thesisen_US
dc.typeDoktorgradsavhandlingen_US


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