Determining Vertical Water Velocities from Seaglider

• Published in: Journal of Atmospheric and Oceanic Technology
• Main Authors: Frajka-Williams, E., Eriksen, C.C., Rhines, P.B., Harcourt, R.R.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2011
• Subjects: Labrador Sea
• Online Access: http://nora.nerc.ac.uk/id/eprint/306147/

Vertical velocities in the world's oceans are typically small, less than 1 cm/s, posing a significant challenge to observation techniques. Seaglider, an autonomous profiling instrument, can be used to estimate vertical water velocity in the ocean to about half a centimeter per second. Using a Seaglider flight model and pressure observations, vertical water velocities are estimated along glider trajectories in the Labrador Sea before, during and after deep convection. Results indicate that vertical velocities in the stratified ocean agree with theoretical WKB-scaling of w, and in the turbulent mixed layer, scale with buoyancy and wind forcing. We estimate that accuracy is within 0.6 cm/s. Due to uncertainties in the flight model, velocities are poor near the surface and deep apogees, and during extended roll maneuvers. Some of this may be improved by using a dynamic flight model permitting acceleration, and by better constraining flight parameters through pilot choices during the mission.