This report summarises visual shipboard ice observations carried out during leg ARK 17/2 of RV Polarstern in August and September 2001, operating along the Gakkel Ridge and at the North Pole. Data on general ice conditions, navigational information as well as photographs taken from the ships bridge are presented. Although most data are subject to large uncertainties due to the different experience of observers, they provide a general and quite representative overview of recent summer conditions in the Transpolar Drift, as seen from a ship. The data and photographs might be of interest as background information for discussions of recent changes of Arctic sea ice, and for comparisons with observations performed in other years. For those who have not seen a sea ice landscape so far, this report might yield first impressions of what the Arctic sea ice cover looks like. For scientists working on remote sensing, modelling, or other aspects of sea ice, the report provides some ground-truth and boundary conditions for their work in the summer of 2001.Ice conditions were characterised by very easily penetrable ice in the first half of the cruise, west of 30°E. There were many large leads with ice concentrations ranging between only 60 and 90%. Only from late August onwards, and east of 30°E, narrower leads and ice concentrations above 90% were observed. At that time, also new ice started to form on the leads. In the late period, sometimes the ship became beset in convergent ice conditions. Initially, melt ponds were observed to cover 10 to 30% of the ice surface. The ponds were ice covered already when we entered the ice in early August. However, the pond ice cover was thick enough to step on (>0.05 m) only after about August 20. Melt ponds became snow covered for some period, before they were visible again. Only after mid-September air temperatures permanently dropped below 0°C, and no snow or surface melting was observed any more.
AWI Organizations > Climate Sciences > Climate Dynamics
AWI Organizations > Climate Sciences > Sea Ice Physics