Wave Glider Observations of Surface Fluxes and Mixed-layer Processes in the Southern Ocean

Air-sea interaction in the Southern Ocean connects the "conveyor belt" overturning circulations in each the major oceans of the world (Atlantic, Pacific, and Indian), providing the long-term memory of the climate system by determining the rates of oceanic heat and carbon storage over tens to hundreds of years as well as the supply of heat to melt Antarctic ice shelves. With the goal of enhancing our ability to study these air-sea interaction processes through sustained autonomous presence in remote locations, our project conducted two deployments of a wave-propelled robotic surface vehicle (Wave Glider) near Palmer Station for extended missions around Drake Passage and the Antarctic Peninsula. Over 3 months in 2016-17 and 4 months in 2019-20, the Wave Glider conducted time series stations and surveys of the Polar Front (one of the intense jets of the Antarctic Circumpolar Current). The vehicle also collected multiple instances of calibration data by positioning itself near the tracks of passing Antarctic research vessels.

Although these first extended deployments revealed some important limitations in the Wave Glider's durability and its ability to maintain solar battery charging in the high-latitude Antarctic, the results have laid the groundwork for future Wave Glider missions. The second field season included a new profiling winch system for subsurface temperature and salinity sampling, and although it only survived for a few profiles it demonstrated its potential in addition to clarifying likely failure modes. Subsequent deployments with a smaller self-recording CTD package have been more successful.