Aspects of Practical Planning and Management of an Ice Passage
About the Author: Captain Uwe Pahl was the master of the German research icebreaker RV Polarstern from 1996 until 2014. Since 2014, he has been the team leader of the construction supervision team of Reederei F. Laeisz for the new Polarstern II. In this first article for Polar Prediction Matters, Uwe Pahl shares his personal view on how challenging it is to navigate such a large vessel through the polar seas.
The German icebreaking research and replenishment vessel RV Polarstern has been in service now for nearly 35 years in both the Arctic and Antarctic seas. During more than one-hundred cruises to the poles, scientists from many different countries have been participating in scientific expeditions, which all were carefully planned in preparation. In addition, the replenishment of the German Antarctic station Neumayer has been a regular main task for RV Polarstern during every austral summer season. Over the course of more than 18 years in command of RV Polarstern, I have experienced how challenging it is to navigate such a large vessel through the polar seas.
Each of the expedition voyage is carefully prepared in advance. In order to get an overview of the general seasonal ice situation, we – the ship’s command– consult current ice charts based on satellites such as the Cryosat 2/ESA-satellite (Fig. 2 and 3). As early as two to three months in advance of a cruise, such ice charts already indicate how the sea-ice situation might develop during the coming voyage. Ice-chart information is thus continuously collected for the strategic expedition planning.
Once Polarstern has left the harbor, the ship’s command and the chief scientist are further planning the voyage track in three levels:
- For the strategic planning of the voyage track all available sources are constantly used in order to find the most convenient passage through the ice with respect to the scientific programme of the expedition. Valuable sources include written reports on ice conditions as well as ice charts based on satellites such as ESA’s Cryosat 2 and JAXA’s Shizuku (AMSR2) processed and submitted to the vessel by the University of Bremen, and charts from the US National Oceanic and Atmospheric Administration (NOAA).
- Regarding the long-range tactical ice and weather assessment, medium-scale radar ice charts are consulted. Weather permitting, helicopter flights up to one-hundred nautical miles from the ship are carried out to explore the current ice situation. The flights provide a good basis to the ships command to decide which track is to be followed.
- Among the short-range tactical observations are high-resolution ice-radar charts obtained with instruments aboard the ship. These are complemented with helicopter reconnaissance flights around the vessel and direct observations from the ship’s crow’s nest. These information are used to guide immediate navigational decisions.
Obviously, ice radar charts are of crucial importance for the planning and performance of voyages in ice-covered waters. A high-resolution picture transmission (HRPT) receiver installed aboard RV Polarstern allows to receive pictures with high spatial resolution of 1.1 km from different weather satellites such as the NOAA-, FENGYUN- and METOP-series up to twelve times a day. Also the ship’s radar and special ice radars are very effective tools for navigation, but require a constant training of the bridge personnel to ensure correct interpretation of the radar pictures.
Against the backdrop of the increasing shipping activities in the Antarctic as well as in the Arctic, in my experience the easy access to real-time ice images is, and will continuously be, of crucial importance for a safe navigation.
A new polar research vessel – RV Polarstern II – is presently under construction. Having operated a research icebreaker in perilous polar seas for many years, I am now contributing to the construction of this new ship, helping to ensure that all challenges of the years ahead are met.