Science Service System

Summary of Proposal OCE0089

TitleImproved sea ice monitoring for the Baltic Sea
Investigator Eriksson, Leif - Chalmers University of Technology, Dept. of Earth and Space Sciences
Team Members
Prof. Borenäs, Karin - Swedish Meteorological and Hydrological Institute – SMHI, Oceanographic Research and Development
Prof. Ulander, Lars - Swedish Defence Research Agency - FOI, Dept. of Radar Systems
Mr. Grafström, Torbjörn - Swedish Meteorological and Hydrological Institute – SMHI, Ice Service
Associate Prof. Håkansson, Bertil - Swedish Meteorological and Hydrological Institute – SMHI, Oceanographic Research and Development
Mr. Pemberton, Per - Swedish Meteorological and Hydrological Institute - SMHI, Oceanographic Research and Development
Dr. Dierking, Wolfgang - Alfred Wegener Institute for Polar and Marine Research, Climate Sciences

The objective of this project is to make a scientific evaluation of the usefulness of TerraSAR-X data for ice type discrimination, ridge detection and determination of ice concentration. The project will be focussed on sea ice in the northern part of the Baltic Sea, which is an area with a high level of winter traffic. The conditions in the Baltic Sea are special because the water salinity is very low and due to the geographical location there is no multi-year ice or icebergs.

In order to cover different ice and weather conditions, satellite images will be acquired from both winter and spring. This will give a time series of data that include conditions that currently are considered as difficult, like high wind speed in leads or over open water, and wet snow or water on top of the ice. A time series like this will make it possible to test the limits of the developed classification algorithms for the specified data. In addition to the TerraSAR-X images we also hope to get access to SAR data from the Canadian Radarsat-2 and the Japanese Advanced Land Observing Satellite (ALOS). This would give the opportunity to compare the characteristics of multi-polarization data from L-band, C-band and X-band, even though it can not be expected that all images can be acquired at the same day.

Data acquisitions will be requested for the three ice seasons 2007, 2007/2008 and 2008/2009. Field campaigns will be organized to coincide with the satellite acquisitions. Depending on ice conditions and available resources for field measurements suitable test areas will be selected within an area that can be covered with one or two TerraSAR-X images. It is estimated that with 12 TerraSAR-X images per ice season it will be possible to cover all ice types and weather conditions that are common in the Baltic Sea. A majority of the TerraSAR-X images will be ordered in Dual Polarization Stripmap mode. For classification of ice type and ice concentration we believe that this mode is the most suitable, but for detection of ice ridges and deformation mapping some images in High Resolution Dual Polarization Spotlight mode will be ordered to evaluate if the higher resolution will improve the results. A few images in Single Polarization ScanSAR mode will also be used to cover larger areas and for investigating scaling problems.

It is anticipated that the main result of the project will be a significantly improved knowledge about the characteristics, possibilities and limitations with multi-polarization X-band SAR for sea ice monitoring. Algorithms for detection of ice ridges, determination of sea ice concentration and classification of ice types will be developed or enhanced. Anticipated funding sources for the project are the Swedish National Space Board and the Swedish Maritime Administration.

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