The aim of this project was to map the thermal field in the upper ocean during the spring to summer transition of 2006/07. This work complements transects that are more commonly occupied across the Drake Passage along the WOCE SR3 line south of Tasmania, and between New Zealand and the Ross Sea. The project will provide the scientific coordination and subsequent analysis of expendable bathythermograph (XBT) casts made in the Southern Ocean from the icebreaker Oden en route to the southwest Ross Sea during the 2006/07 austral summer. A large number of XBTs were dropped along the transit track starting when the Oden reached the sea ice edge. The acquired data will be edited, contoured and compared with historical observations from the same region. Particular attention will be paid to temporal and spatial changes in temperature and mixed layer depth versus connections to seasonal and interannual variability of the sea ice cover and the state of atmospheric forcing. Measurements will be reported to the appropriate archives, and provided to interested investigators with related Oden projects. We anticipate results that could help to address the nature of warming in the Southern Ocean, along with the effectiveness of icebreakers-ofopportunity to collect these data.

A total of 156 XBTs were deployed through 1700 hrs on 26 December with the last deployment dropped just before the Oden exited the pack ice. Most of the XBTs provided complete records with only about 10% yielding partial records owing to snagging of the transmission wires on ice before they reached their depth limits.