Abstract

Quantifying and understanding the processes driving ocean mixing is fundamental to improving heat transport estimations and climate projections. Underwater autonomous gliders are a new platform that, compared to more conventional methods such as free-failing profilers, increase the number of available measurements by an order of magnitude. In 2016, a glider deployment in Ryder Bay, a 520 m deep bay adjacent to the British Antarctic Survey station at Rothera, collected both hydrographic and microstructure data, obtaining the first direct (not-inferred) measurements of dissipation of turbulent kinetic energy and dissipation of temperature variance in the west Antarctic. Elevated dissipation estimates of O(1×10^-8 W kg^-1) and heat fluxes up to approximately 12.6 W m^-2 are found above a topographic sill. Contrasting values of O(1×10^-10 W kg^-1) and approximately 0.2 W m^-2 are observed in the deep basin, this suggests that the topography of the bay significantly modulates both the vertical mixing and upward heat flux. These results are currently being analysed in conjunction with mooring-based velocity data and the 20-year Rothera Time Series to identify the dominant controls on summertime mixing.