Improved dissipation rate estimation method based on time-varying glide parameter analysis of underwater gliders

Turbulent mixing is a key process in ocean circulation. An underwater glider is an ideal platform for turbulence measurement; however, owing to the influence of multisource uncertainties, such as corrosion and fouling, there are deviations in the glide speed, which lead to errors in the estimation of the dissipation rate of turbulent kinetic energy (TKE). To study the effect of uncertainty, an error model of the dissipation rate was established, and the relationship between the changes in the glide parameters and those in the dissipation rate was analyzed. To correct the estimation error of the dissipation rate, a calibration model for glide parameters was built using a simulated annealing algorithm (SAA) and verified using experimental data obtained from a glider equipped with an electromagnetic current sensor. The accuracy of the error model of the dissipation rate was verified through turbulence observations for 127 days. Results showed that after continuous observation of 414 profiles, the method proposed in this study can reduce the error in dissipation rate by 59% in the diving phase and 20% in the climbing phase, providing an effective means for reducing uncertainties in turbulent microstructure studies.