The GPCTD is a modular, low-power profiling instrument for autonomous gliders with the high accuracy necessary for research, inter-comparison with moored observatory sensors, updating circulation models, and leveraging data collection opportunities from operational vehicle missions. The externally powered, continuously pumped CTD consumes only 175 mW recording at 1 Hz (190 mW for real-time data). One Alkaline D cell could operate the CTD continuously for 114 hours (9.5 days at 50% duty cycle, profiling continuously at 1 Hz on every glider upcast); one Lithium DD cell could provide 48 days continuous profiling on every upcast. Data are output in engineering units.
The GPCTD can optionally be equipped with an SBE 43F Dissolved Oxygen sensor.