Show Abstract
We conducted mooring observations with acoustic Doppler current profilers (ADCPs) and conductivity-temperature (CT) recorders inside the Cape Darnley polynya throughout winter for the first time. Two moorings were deployed near the shore (a1: bottom depth 183 m) and the shelf edge (a2: bottom depth 270 m). Each mooring was equipped with an Ice Profiling Sonar (IPS: ASL Environmental Sciences, IPS4 420 kHz), an upward-looking acoustic Doppler current profiler (ADCP: RD Instruments Workhorse Sentinel 300 kHz), and conductivity-temperature recorders (CT-recorders: SeaBird SBE-37 MicroCAT) from the top. The ADCPs at a1 and a2 measured the volume backscatter strength (SV) in addition to the current velocity for 9 and 10 layers of bin, respectively, with the 8 m interval. The pre-deployment calibration demonstrated a temperature accuracy of 2 mK and a salinity accuracy of 4 X 10-3. ADCP and CT-recorder depths were calculated from the pressure by the IPS pressure sensor and the tilt measured by the ADCP with an assumption that the mooring line was straight. In this region, the iceberg tongue in the east creates a risk of an iceberg attack on the moorings. In fact, the mooring at a2 was attacked by an iceberg twice, which was recorded by the pressure sensor as rapid dives. Fortunately, both moorings survived for one year.