Merckelbach, Lucas, Berger, Anja, Krahmann, Gerd , Dengler, Marcus and Carpenter, Jeffrey R. (2019) A dynamic flight model for Slocum gliders and implications for turbulence microstructure measurements. Journal of Atmospheric and Oceanic Technology, 36 . pp. 281-296. DOI 10.1175/JTECH-D-18-0168.1.

Preview	Text jtech-d-18-0168.1.pdf - Accepted Version Available under License Creative Commons: Attribution 4.0. Download (3MB) | Preview
Preview	Text jtech-d-18-0168.1.pdf - Published Version Download (2MB) | Preview

Abstract

The turbulent dissipation rate ɛ is a key parameter to many oceanographic processes. Recently gliders have been increasingly used as a carrier for microstructure sensors. Compared to conventional ship-based methods, glider-based microstructure observations allow for long duration measurements under adverse weather conditions, and at lower costs. The incident water velocity U is an input parameter for the calculation of the dissipation rate. Since U can not be measured using the standard glider sensor setup, the parameter is normally computed from a steady-state glider flight model. As ɛ scales with U2 or U4, depending whether it is computed from temperature or shear microstructure, flight model errors can introduce a significant bias. This study is the first to use measurements of in-situ glider flight, obtained with a profiling Doppler velocity log and an electromagnetic current meter, to test and calibrate a flight model, extended to include inertial terms. Compared to a previously suggested flight model, the calibrated model removes a bias of approximately 1 cm s−1 in the incident water velocity, which translates to roughly a factor of 1.2 in estimates of the dissipation rate. The results further indicate that 90% of the estimates of the dissipation rate from the calibrated model are within a factor of 1.1 and 1.2 for measurements derived from microstructure temperature sensors and shear probes, respectively. We further outline the range of applicability of the flight model.

Actions (login required)

View Item