Blar i forfatter Artikler, rapporter og annet (fysikk og teknologi) "Gerland, Sebastian"

Viser treff 1-12 av 12

    • Assessing polarimetric SAR sea-ice classifications using consecutive day images 

      Moen, Mari-Ann; Anfinsen, Stian Normann; Doulgeris, Anthony Paul; Renner, Angelika; Gerland, Sebastian (Journal article; Tidsskriftartikkel; Peer reviewed, 2015)
      This paper investigates automatic segmentation and classification of C-band, polarimetric synthetic aperture radar (SAR) satellite images of Arctic sea ice under freezing conditions prior to melt. The objective is to investigate the robustness of the results obtained under slightly varying environmental conditions and different viewing geometries. Initially, three geographically overlapping SAR ...

    • Can we extend local sea-ice measurements to satellite scale? An example from the N-ICE2015 expedition 

      Rösel, Anja; King, Jennifer; Doulgeris, Anthony P.; Wagner, Penelope M.; Johansson, Malin; Gerland, Sebastian (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-12-17)
      Knowledge of Arctic sea-ice conditions is of great interest for Arctic residents, as well as for commercial usage, and to study the effects of climate change. Information gained from analysis of satellite data contributes to this understanding. In the course of using in situ data in combination with remotely sensed data, the question of how representative local scale measurements are of a wider ...

    • Comparison of feature based segmentation of full polarimetric SAR satellite sea ice images with manually drawn ice charts 

      Moen, Mari-Ann; Doulgeris, Anthony Paul; Anfinsen, Stian Normann; Renner, Angelika H.H.; Hughes, Nick; Gerland, Sebastian; Eltoft, Torbjørn (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      In this paper we investigate the performance of an algorithm for automatic segmentation of full polarimetric, synthetic aperture radar (SAR) sea ice scenes. The algorithm uses statistical and polarimetric properties of the backscattered radar signals to segment the SAR image into a specified number of classes. This number was determined in advance from visual inspection of the SAR image and by ...

    • Consistent ice and open water classification combining historical synthetic aperture radar satellite images from ERS-1/2, Envisat ASAR, RADARSAT-2 and Sentinel-1A/B 

      Johansson, Malin; Malnes, Eirik; Gerland, Sebastian; Cristea, Anca; Doulgeris, Anthony Paul; Divine, Dmitry V; Pavlova, Olga; Lauknes, Tom Rune (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-17)
      Synthetic Aperture Radar (SAR) satellite images are used to monitor Arctic sea ice, with systematic data records dating back to 1991. We propose a semi-supervised classification method that separates open water from sea ice and can utilise ERS-1/2, Envisat ASAR, RADARSAT-2 and Sentinel-1 SAR images. The classification combines automatic segmentation with a manual segment selection stage. The ...

    • Consistent ice and open water classification combining historical synthetic aperture radar satellite images from ERS-1/2, Envisat ASAR, RADARSAT-2, and Sentinel-1A/B 

      Johansson, Malin; Malnes, Eirik; Gerland, Sebastian; Cristea, Anca; Doulgeris, Anthony Paul; Divine, Dmitry V; Pavlova, Olga; Lauknes, Tom Rune (Journal article; Tidsskriftartikkel, 2020)

    • Does your lab use social media? Sharing three years of experience in science communication 

      Pavlov, Alexey K.; Meyer, Amelie; Rösel, Anja; Cohen, Lana; King, Jennifer; Itkin, Polona; Negrel, Jean; Gerland, Sebastian; Hudson, Stephen R.; Dodd, Paul A.; de Steur, Laura; Mathisen, Stig; Cobbing, Nick; Granskog, Mats A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-06-27)
      Effective science communication is essential to share knowledge and recruit the next generation of researchers. Science communication to the general public can, however, be hampered by limited resources and a lack of incentives in the academic environment. Various social media platforms have recently emerged, providing free and simple science communication tools to reach the public and young people ...

    • Imaging Sea Ice Structure by Remote Sensing Sensors 

      Eltoft, Torbjørn; Doulgeris, Anthony Paul; Brekke, Camilla; Solbø, Stian; Gerland, Sebastian; Hanssen, Alfred (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-06-14)
      This paper will investigate how new developments in remote sensing and sensor technologies can be applied to image the structure of the sea ice surface. Both segmentation of multipolarimetric synthetic aperture radar images and strategies for the analyses of polarimetric SAR data of sea ice are addressed. The analysis is based on a Radarsat 2 PolSAR scene of from the Fram Strait in September ...

    • Late summer sea ice segmentation with multi-polarisation SAR features in C- and X-band 

      Fors, Ane Schwenke; Brekke, Camilla; Doulgeris, Anthony Paul; Eltoft, Torbjørn; Renner, Angelika; Gerland, Sebastian (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-09-01)
      In this study we investigate the potential of sea ice segmentation by C- and X-band multi-polarisation synthetic aperture radar (SAR) features during late summer. Five high-resolution satellite SAR scenes were recorded in the Fram Strait covering iceberg- fast first-year and old sea ice during a week with air temperatures varying around zero degrees Celsius. In situ data consisting of sea ice ...

    • On the potential of hand-held GPS tracking of fjord ice features for remote-sensing validation 

      Negrel, Jean; Gerland, Sebastian; Doulgeris, Anthony Paul; Lauknes, Tom Rune; Rouyet, Line (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-12-14)
      Research on young thin sea ice is essential to understand the changes in the Arctic. But it is also the most challenging to investigate, both in situ and from satellites. If satellite remote sensing techniques are developing rapidly, fieldwork remains crucial for the mandatory validation of such data. In April 2016, an Arctic fieldwork campaign was conducted at Kongsfjorden, Svalbard. This campaign ...

    • On the relation between polarimetric synthetic aperture radar (SAR) features and sea ice melt pond fraction 

      Fors, Ane Schwenke; Doulgeris, Anthony Paul; Renner, Angelika; Brekke, Camilla; Gerland, Sebastian (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-11-12)
      In this study we examine the relationship between sea ice melt pond fraction and two polarimetric C-band synthetic aperture radar (SAR) features. Three high-resolution SAR scenes were recorded in the Fram Strait in late summer 2011, covering iceberg-fast first-year and old sea ice. In addition, melt pond fraction was retrieved from photographs recorded during a helicopter flight at the study area. ...

    • Signature of Arctic first-year ice melt pond fraction in X-band SAR imagery 

      Fors, Ane Schwenke; Divine, Dmitry V; Doulgeris, Anthony Paul; Renner, Angelika; Gerland, Sebastian (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-03-23)
      In this paper we investigate the potential of melt pond fraction retrieval from X-band polarimetric synthetic aperture radar (SAR) on drifting first-year sea ice. Melt pond fractions retrieved from a helicopter-borne camera system were compared to polarimetric features extracted from four dual-polarimetric X-band SAR scenes, revealing significant relationships. The correlations were strongly dependent ...

    • Winter storms accelerate the demise of sea ice in the Atlantic sector of the Arctic Ocean 

      Graham, Robert M.; Itkin, Polona; Meyer, Amelie; Sundfjord, Arild; Spreen, Gunnar; Smedsrud, Lars H.; Liston, Glen E.; Cheng, Bin; Cohen, Lana; Divine, Dmitry; Fer, Ilker; Fransson, Agneta; Gerland, Sebastian; Haapala, Jari; Hudson, Stephen R.; Johansson, Malin; King, Jennifer A.; Merkouriadi, Ioanna; Peterson, Algot Kristoffer; Provost, Christine; Randelhoff, Achim; Rinke, Annette; Rösel, Anja; Sennechael, Nathalie; Walden, Von P.; Duarte, Pedro; Assmy, Philipp; Steen, Harald; Granskog, Mats A. (Journal article; Peer reviewed, 2019-06-25)
      A large retreat of sea-ice in the ‘stormy’ Atlantic Sector of the Arctic Ocean has become evident through a series of record minima for the winter maximum sea-ice extent since 2015. Results from the Norwegian young sea ICE (N-ICE2015) expedition, a five-month-long (Jan-Jun) drifting ice station in first and second year pack-ice north of Svalbard, showcase how sea-ice in this region is frequently ...