Speaker: Jesse Cusack (SIO)
Title: Observation of a Large Lee Wave in the Southern Ocean
Abstract: In the Southern Ocean, breaking lee waves are thought to be one of the processes responsible for generating turbulent mixing that drives the global overturning circulation. However, observations of them are scarce. This talk will focus on the analysis of a single wave event that was detected by two autonomous profiling floats as they travelled through the Drake Passage in 2011. A model of float motion was developed and used to estimate vertical water velocity from profiling speed. Fine scale estimates of the turbulent dissipation rate were elevated above background levels in the wave, but still orders of magnitude smaller than the wave energy flux, suggesting that the wave was not actively breaking. These results provide the first unambiguous observation of a lee wave in the Southern Ocean with simultaneous measurements of its energetics and dynamics.