Analysis and interpretation of multi-channel SAR signatures of sea ice

Ph.D. student:
Mari-Ann N Moen

Supervisors:
Torbjørn Eltoft, Sebastian Gerland and Stian Normann Anfinsen

Project description:
SAR images of sea ice reveal large variability in appearance as a function of imaging conditions (incidence angle, polarization, frequency), sea ice conditions (surface roughness, ice type), and meteorological conditions during acquisition. This project aims to further improve understanding of microwave scattering and SAR imaging of sea ice by investigating how radiometric, statistical and polarimetric signal properties relate to physical properties of sea ice surface. An ultimate goal of this study is to enable robust and reliable classification of sea ice from SAR data. Such a classification tool would be valuable for both operational sea ice monitoring services and climate researchers.

Publications:
Hughes, N., A.P. Doulgeris, S. Gerland, A. Renner, M.-A. Moen, T. Eltoft, R. Hall, C. Brekke, T. Robertson, O. Brandt, Z. Li and M. Zugmuntowska: Integrated studies of multi-polarimetric SAR over sea ice, Presented at SEASAR 2012, Tromsø, Norway, , 18-22 June, 2012

Land Cover Change Detection with Single and Multi-Polarization SAR Imagery

Ph.D. student:
Vahid Akbari

Supervisors:
Torbjørn Eltoft, Sebastiano B. Serpico and Anthony Doulgeris

Project description:
Satellite Remote Sensing is one of the most important technologies to monitor processes that occur on the surface of the Earth. Multi-temporal analysis of SAR data allows monitoring changes in land cover using properties of the backscatter intensity. Polarimetric SAR (PolSAR) data are expected to improve the ability to infer change information from multi-temporal data. The research includes the segmentation from multi-dimensional time series of SAR images of Arcrtic Glaciers, which can enable monitoring of change and dynamic properties. Identifying and monitoring fluctuations in glacier facies provides a mean to track climate change.The goal is improving the accuracy and robustness of surface cover classification using multi-frequency, multi-polarization scenario. The main concentration is on using Gaussian Markov Random Field (MRF) models to exploit statistical spatial correlation of intensity levels among neighboring pixels and a stochastic and iterative change detection algorithm based on MRF models is developed during this research project.

Publications:
Akbari, V., A.P. Doulgeris and T. Eltoft: Monitoring glacier changes using multitemporal multipolarization SAR images, IEEE Trans. Geosci. Remote Sens., vol. 52, no. 6, pp. 3729-3741, June, 2014
Akbari, V., A.P. Doulgeris, A.P., and T. Eltoft: Non-Gaussian clustering of SAR images for glacier change detection, Proc. ESA Symposium 2010, Bergen, Norway, 4 pp., 28 June-2 July, 2010
Akbari, V., A.P. Doulgeris, G. Moser, T. Eltoft, S.N. Anfinsen and S. Serpico: A textural–contextual model for unsupervised segmentation of multipolarization synthetic aperture radar images, IEEE Trans. Geosci. Remote Sens., vol. 51, no. 4, pp. 2442-2453, April, 2013
Akbari, V., A.P. Doulgeris, T. Eltoft: Time series analysis of multi-polarisation synthetic aperture radar Images with a Textural-Contextual Model, Proc. EUSAR 2012, Nuremberg, Germany, pp. 726-729, 23-26 April, 2012
Akbari, V., G. Moser, A.P. Doulgeris, S.N. Anfinsen, T. Eltoft and S.B. Serpico: A K-Wishart Markov random field model for clustering of polarimetric SAR imagery, Proc. IGARSS 2011, Vancouver, Canada, 1357-1360, 24-29 July, 2011
Akbari, V., S.N. Anfinsen, A.P. Doulgeris and T. Eltoft: The Hotelling-Lawley trace statistic for change detection in polarimetric SAR data under the complex Wishart distribution, Proc. IGARSS 2013, Melbourne, Australia, 5 pp., 22-26 July, 2013
Akbari, V., Y. Larsen, A.P. Doulgeris and T. Eltoft: The impact of terrain correction of polarimetric SAR data on glacier change detection, Proc. IGARSS 2012, Munich, Germany, pp. 5129-5132, 22-27 July, 2012
Akbari. V., S. N. Anfinsen, A. P. Doulgeris, T. Eltoft, G. Moser, and S. B. Serpico: Polarimetric SAR Change Detection with the Complex Hotelling-Lawley Trace Statistic, IEEE Trans. Geosci. Remote Sens, vol. 54, no. 7, pp. 3953-3966, July, 2016
Doulgeris, A.P., Akbari, V., and Eltoft, T.: Automatic PolSAR segmentation with the U-distribution and Markov random fields, Proc. EUSAR 2012, Nuremberg, Germany, pp. 183-186, 23-26 April, 2012

Study, improvement, and validation of the sea surface statistics used along with SAR data for the determination of ocean wave metrics

Ph.D. student:
Faozi Saïd

Supervisors:
Harald Johnsen, Torbjørn Eltoft

Project description:
The determination of geophysical parameters, such as ocean wave spectra, ocean currents, and sea surface wind, has a critical role in weather forecasting, scientific and climate studies. Currently, such parameters are most effectively estimated on a global scale using remote sensing technology such as SAR. However, the quality of ocean products derived from SAR data may be affected by certain aspects of the sea surface statistical model used. It is strongly believed that a more accurate description of such model may result in an improved Doppler frequency shift, real aperture radar modulation transfer function, and normalized radar cross-section. The end results will be more accurate sea surface wind retrieval, ocean wave spectra estimation, ocean currents, as well as other key ocean/wave parameters derived from SAR data.

Seasonal classification and characterization of sea ice from multi-sensor remote sensing data

Ph.D. student:
Ane Fors

Supervisors:
Anthony Doulgeris, Camilla Brekke, Sebastian Gerland and Torbjørn Eltoft

Project description:
Arctic sea ice extent has sharply declined for the last decades and knowledge about the summer sea ice characteristics is important in understanding the decline. As in situ measurements in the Arctic are sparse, and cloud cover in the Arctic summer months often confines the use of optical satellite measurements, cloud independent SAR measurements have a great advantage in monitoring Arctic summer sea ice cover. My projects focuses on detection of melt ponds and leads, and mapping of their fractional coverage. An important aspect of this work is feature extraction and studies of methods for sea ice classification on multiple spatial scales. The goal of the project is to develop robust methods for summer sea ice classification for use in climate studies.

Publications:
Fors, A. S., Brekke, C., Gerland, S., Doulgeris, A.P. and Eltoft,T.: Extraction of late summer sea ice properties from polarimetric SAR features in C- and X-band, Proc. POLinSAR 2015, Frascati, Italy, , 26-30 January, 2015
Fors, A. S., C. Brekke, A. P. Doulgeris, T. Eltoft, A. H. H. Renner and S. Gerland: Late-summer sea ice segmentation with multi-polarisation SAR features in C and X band, The Cryosphere, vol. 10, no. 1, pp 401-415, February, 2016
Fors, A. S., C. Brekke, S. Gerland, A. P. Doulgeris, and J. F. Beckers: Late Summer Arctic Sea Ice Surface Roughness Signatures in C-Band SAR Data, IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, vol. 9, no. 3, pp. 1199-1215, March, 2016
Fors, A. S., D. V. Divine, A. P. Doulgeris, A. H. H. Renner and S. Gerland: Signature of Arctic first-year ice melt pond fraction in X-band SAR imagery, , , , 2016
Fors, S. Ane, A. P. Doulgeris, A. H. H. Renner, C. Brekke and S. Gerland: On the releation between polarimetric synthetic aperture radar (SAR) feature and sea ice melt pond fraction, Proc. IGARSS 2015, Milan, Italy, , , 2015

Marine Targets Detection and Discrimination based on SAR data

Ph.D. student:
Ding Tao

Supervisors:
Camilla Brekke, Stian Normann Anfinsen and Torbjørn Eltoft

Project description:
In the high latitudes, maritime activities are emerging constantly, because of new shipping lines, oil findings, etc. Navigation and monitoring for marine transits within those regions are increasingly required for both civil and military purposes. Polarimetric Synthetic Aperture Radar (SAR) are mainly exploited in the project due to its all-time and all-weather capabilities. The challenge is to investigate the potential of many existing methods and then develop improved algorithms combining SAR data and other available information. In addition, maritime environment study is very important to the project, i.e. variable sea conditions, sea ice and icebergs. Currently, the study regions are focused on northern coastal waters of Norway and other Arctic areas. However, the algorithms could also be useful for other regions.

Publications:
Anfinsen, S.N., D. Tao, and C. Brekke: Improved target detection in polarimetric SAR images by use of Mellin kind statistics, Proc. POLinSAR 2011, Frascati, Italy, 4 pp., 24-28 January, 2011
Tao, D., A. Doulgeris and C. Brekke.: Segmentation based CFAR Detection Algorithm using Truncated Statistics, IEEE Trans. Geosci. Remote Sens., vol. 54, no. 5, pp. 2887-2898, May, 2016
Tao, D., A.P. Doulgeris and C. Brekke: Sea clutter contamination test with log-cumulants, Proc. SPIE Remote Sensing, Edinburgh, U.K., vol. 8536, 14 pp., 24-27 September, 2012
Tao, D., Brekke, C., Anfinsen, S. N.: An Experimental Study on Ship Detection based on the Fixed-Point Polarimetric Whitening Filter, Proc. of SPIE Remote Sensing, Prague, Czech Republic, vol. 8180, 9 pp., 19-22 September, 2011
Tao, D., S.N. Anfinsen and C. Brekke: Ocean clutter modeling for ship detection, Proc. SEASAR 2012, Tromsø, Norway, , 18-22 June, 2012
Tao, D., S.N. Anfinsen and C. Brekke: A comparative study of sea clutter covariance matrix estimators, IEEE Geosci. Remote Sensing Lett., vol. 11, no. 5, pp. 1010-1014, May, 2014
Tao, D., S.N. Anfinsen and C. Brekke: Robust CFAR detector based on truncated statistics in multiple target situations, IEEE Trans. Geosci. Remote Sens., vol. 54, no. 1, pp. 117-134, January, 2016
Tao, D., S.N. Anfinsen and C. Brekke: A ship detection algorithm based on truncated statistics, Proc. EUSAR 2014, Berlin, Germany, 4 pp., 3-5 June, 2014

Oil Spill Detection and Characterization by Multispectral and Microwave Remote Sensing

Ph.D. student:
Stine Skrunes

Supervisors:
Camilla Brekke, Torbjørn Eltoft, Rune Storvold

Project description:
Oil spills, both deliberate discharges and accidents, are an important environmental problem, posing a threat to the marine and coastal environment. Remote sensing, particularly with SAR, has become an important tool for oil spill detection and monitoring. SAR is especially useful in Arctic areas due to the day and night, all weather capabilities. One shortcoming of SAR is the fact that several natural phenomena, called look-alikes, have the same appearance as oil spills in SAR imagery. This includes natural films, grease ice, low wind areas etc. Recent advances in sensor technology, e.g. multi-polarization options, are likely to improve the possibilities for detection, characterization and for classification between oil spills and look-alikes, and between different types of oils. The overall aim of this project is to develop new methodologies based on multi-spectral radiometric data and multi-polarization and multi-frequency SAR data together with other auxiliary information to enable improved detection and characterization of oil slicks and their look-alikes in Arctic oceans.

Publications:
Skrunes, S., Brekke, C., Eltoft, T, Miegebielle, V.: An experimental study of X-band synthetic aperture radar (SAR) imagery for marine oil slick monitoring, Proc. 36th AMOP Technical Seminar on Environmental Contamination and Response, Halifax, Canada, 17 pp., 4-6 June, 2013
Skrunes, S., C. Brekke and T. Eltoft: An experimental study on oil spill characterization by multi-polarization SAR, Proc. EUSAR 2012, Nuremberg, Germany, pp. 139-142, 23-26 April, 2012
Skrunes, S., C. Brekke and T. Eltoft: A comprehensive analysis of polarimetric features for oil spill characterisation, Proc. SEASAR 2012, Tromsø, Norway, 8 pp., 18-22 June, 2012
Skrunes, S., C. Brekke and T. Eltoft: Oil spill characterization with multi-polarization C- and X-band SAR, Proc. IGARSS 2012, Munich, Germany, pp. 5117-5120, 22-27 July, 2012
Skrunes, S., C. Brekke and T. Eltoft: Ocean surface slick characterization by multi-polarization Radarsat-2 data, Proc. SPIE Remote Sensing 2012, Edinburgh, U.K., 15 pp., September, 2012
Skrunes, S., C. Brekke and T. Eltoft: Characterization of Marine Surface Slicks by Radarsat-2 Multipolarization Features, IEEE Trans. Geosci. Remote Sens., vol. 52, no.9, pp. 5302-5319, September, 2014

Multi-channel data analysis of sea ice

Ph.D. student:
Jakob Grahn

Supervisors:
Camilla Brekke, Torbjørn Eltoft, Wolfgang Dierking

Project description:
The development of Synthetic Aperture Radar (SAR) during the past decades has lead to systems operating in a variety of different acquisition modes, particularly in different polarisation and frequency modes. By combining different modes, retrieval of detailed geophysical information is possible. This project focuses on the utilisation of multiple channel SAR data for analysing sea ice. Special consideration is taken to the combined use of polarisation and frequency channels for retrieval of ice properties and ice type discrimination.

Publications:
Grahn, J, Brekke, C., Eltoft, T. Dierking, W., and Gerland, S.: Retrieval of First Year Ice Surface Slinity with Fully Polarimetric SAR, Proc. POLInSAR 2015, Frascati, Italy, 5 pp., 26-30 January, 2015
Grahn, J., Brekke, C., Eltoft, T., and Holt, B.: On sea ice characterisation by multi-frequency SAR, Proc. 2013 European Space Agency Living Planet Symposium, Edinburgh, United Kingdom, 6 pp., 9-13 September, 2013

Tracking Arctic sea ice dynamics using satellite-borne synthetic aperture radar

Ph.D. student:
Thomas Kræmer

Supervisors:
Camilla Brekke, Harald Johnsen, and Torbjørn Eltoft

Project description:

Publications:
Kræmer, T. and C. Brekke: Short-Time Ice Drift and Deformation Measurements Using Multi-Mission Synthetic Aperture Radar, Proc. of Port and Ocean Engineering under Arctic Conditions, 10, 14-18 June, 2015
Kræmer, T. C, Brekke: Short-time ice drift and deformation measurements using multi-mission synthetic aperture radar, Proc. Port and Ocean Engineering under Arctic Conditions, 10 pp., June, 2015
Kræmer, T., C. Brekke, T. Eltoft: Sea ice motion estimation in the marginal ice zone using dual-polarization SAR, Proc. Earth Observation and Cryosphere Science 2012, Frascati, Italy, 4, 13-16 November, 2012
Kræmer, T., H. Johnsen and C. Brekke: Emulating Sentinel-1 Doppler Radial Ice Drift Measurements using Envisat ASAR Data, IEEE Trans. Geosci. Remote Sens., vol. 53, no. 12, pp. 6407-6418, December, 2015

Theoretical and experimental studies of electromagnetic scattering from snow and sea ice using ground based SAR tomography

Ph.D. student:
Temesgen Gebrie Yitayew

Supervisors:
Torbjørn Eltoft and Laurent Ferro-Famil

Project description:
Snow and sea ice characteristics have been studied using electromagnetic (EM) remote sensing techniques. Synthetic Aperture Radar (SAR) is among the most widely used measurement techniques, due to its low sensitivity to weather conditions, to its high resolution imaging capabilities as well as its sensitivity to volumetric scattering effects. Structural parameters of volume scatterers in the Cryosphere such as snow depth and ice layering are important inputs for ecological process modeling and enable monitoring and understanding of Eco-system changes. However, using the conventional 2-D SAR system, it is difficult to characterize the snow and sea ice volume quantitatively as the 3-D scene scattering properties are projected onto the 2-D azimuth-range plane. SAR tomography is the extension of conventional 2-D SAR imaging to three dimensions. By coherently combine images acquired from several parallel flight tracks, it allows direct imaging of volume scattering layers and is, therefore, a promising technique for the study of volumetric properties. In this project, we will focus on Very High Resolution (VHR) characterization of the EM scattering properties of snow and sea ice using a Ground-Based tomographic SAR system (GB-SAR). One of the main objectives is to develop improved tomographic focusing strategies related to the GB-SAR system. Another main objective is to establish a 3-D VHR image of the snow/sea ice layers and study the vertical distribution of scatterers within the snow/ice volume.

Publications:
Yitayew, T.G., A.P. Doulgeris and C. Brekke: Multi-sensor data fusion and feature extraction for forestry applications, Proc. IGARSS 2012, Munich, Germany, pp. 4982-4985, 22-27 July, 2012

Compact Polarimetric Synthetic Aperture Radar for characterization and detection of oil spills and newly formed sea ice

Ph.D. student:
Martine M. Espeseth

Supervisors:
Camilla Brekke, Cathleen Jones, and Arnt-Børre Salberg

Project description:

Publications:
Espeseth, M. M., C. Brekke and S. N. Anfinsen: Hybrid-Polarity and Reconstruction Methods for Sea Ice with L- and C-band SAR, IEEE Geoscience and Remote Sensing Letters, vol. 13, no. 3, pp. 467-471 , March, 2016

Scattering characteristics of oil slicks and look-alikes inferred from polarimetric SAR data

Ph.D. student:
Alberto Arienzo

Supervisors:
Torbjørn Eltoft, Camilla Brekke, Anthony Doulgeris, Harald Johnsen, and Veronique Miegebielle

Project description:

Numerical Modeling and Analysis of Sea ice with microwave remote sensing

Ph.D. student:
Xu Xu

Supervisors:
Camilla Brekke, Anthony Doulgeris, and Frank Melandsø

Project description:

Contact Info

University of Tromsø
Barents Remote Sensing School
Department of Physics and Technology
NO-9037 Tromsø
Norway
Tel: +47 776 45150
Fax: +47 776 45580
Visiting address

Auroral Observatory
Prestvannveien 40
Tromsø, Norway
Head of school

Prof. Torbjørn Eltoft
torbjorn.eltoft (at) uit.no
Tel: +47 776 45184
News

Mar 17, 2017
PhD defence
Congratulations to Ane Fors for successfully defending her PhD dissertation titled: "Investigations of summer sea ice with X and C-band multi-polarimetric synthetic aperture radar (SAR)" on 17 March.