Abstract
This report describes surface water temperature measurements obtained by an autonomous observing instrument “UpTempO” as a part of RV Mirai Arctic cruise in 2014, MR14-05. The UpTempO is a drifting buoy consisting of an underwater thermistor chain, carrying 16 thermistors and 3 pressure sensors, and a surface floating unit for Iridium satellite communication with sensors of sea surface temperature and sea level pressure. Three UpTempOs have been deployed from RV Mirai in the ice-free Chuckhi Plateau. UpTempOs have successfully collected the near-surface temperature data to reveal seasonal change of surface layer heat content during a transition from late summer to mid-winter. The past Mirai expeditions, aiming to reveal the yearlong air-sea heat exchange in the Arctic, has faced difficulties to continue the observation after the surface freezing onsets since RV Mirai is not designed to sufficiently resist pressures from surrounding ice floes. Then, deploying the autonomous instrument such as UpTempO from the ship could make it possible to carry out the prolonged observation even the freezing onset onward.
