Navigating through ice-covered waters on board the research vessel 'Polarstern'
The German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) is working on a satellite-based system for substantially improving ship navigation in ice-affected waters. The Earth observation satellites TerraSAR-X and TanDEM-X provide the high-resolution images needed to make this possible. Scientists from the Alfred Wegener Institute (AWI) – the Helmholtz Centre for Polar and Marine Research based in Bremerhaven – are currently on their way to Antarctica on board the research vessel 'Polarstern' to test the practicality of this technique.
Challenges of a polar ocean – freezing temperatures, storms and icebergs
The decline of arctic sea ice during the summer period will open new routes for the shipping sector, permitting the development of fossil fuel resources and also cutting the travel time for navigation by commercial vessels. But the risks presented by these new maritime routes are high; freezing temperatures, storms and icebergs pose a challenge for both crews and ships. In the event of an emergency situation, search and rescue missions would be significantly set back by the lack of marine infrastructure in these regions. In addition, there is insufficient real-time data that ships could use for navigating through polar oceans.
New satellite-based systems will ensure greater security in real time
DLR is developing satellite-based systems geared towards enhancing safety along maritime routes. They are based on high-resolution images provided by the radar satellites TerraSAR-X and TanDEM-X. The satellites transmit the images directly to the DLR ground station in Neustrelitz, where they are processed in near real time. "We are developing a suitable processing chain," says Egbert Schwarz from the Real-Time Data Center at the DLR site in Neustrelitz. An algorithm developed at the DLR research centre in Bremen automatically analyses the data for the presence of ships. "The integrated solution includes a fully-automated delivery system that sends the data products directly to the ship after processing. It also classifies icebergs and marks them as potential hazards," Schwarz adds.
Travelling the Weddell Sea
DLR and AWI are currently testing the extent to which this method is applicable on board the research vessel 'Polarstern' in the Weddell Sea off the coast of Antarctica. The primary purpose of the 'Polarstern' expedition is to study the relationship between winter ice cover and changes in the population of Antarctic krill. "The satellite images not only help us find the best routes through the ice, they also identity suitable ice floes on which to conduct scientific experiments over several days," says Thomas Krumpen, a sea ice physicist at AWI. In addition, he and his team on board 'Polarstern' use a helicopter-based device named 'EM-Bird' that AWI developed specifically to measure the ice thickness. Until now, satellite-based methods have proved unable to measure ice thickness with the required precision. In future, the DLR Research Centre for Maritime Safety in Bremen and the DLR Microwaves and Radar Institute in Oberpfaffenhofen will use a combination of the ice information acquired by the helicopter measuring device and the satellites to improve the system. The cooperation between DLR and AWI in this field will include additional research expeditions in the Arctic.