Turbulence Observations in the Northern Gulf of Mexico from a Slocum Glider
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2018 IEEE. In this study, we show that a Webb Slocum G2 deepwater glider equipped with a microstructure package can be used to quantify the horizontal and vertical structure of turbulence. We present data obtained during the 2016 Gulf of Mexico Mixing (GoMix) experiment, which took place at the edge of the continental slope of the northern Gulf of Mexico in September 2016. The glider was operated in a yo-yo mode and collected data from 20m (base of the surface mixed layer) to ~5m above the bottom. The observational results show that turbulence is strongest in the thermocline with maximum values greater than 10 -6 m 2 s -3 . Enhanced turbulent layers are often measured below the thermocline, revealing the pancake-like structure of the turbulent field in the ocean. The turbulent dissipation rate down to about 3 10 -11 m 2 s -3 is measured in the most quiescent layers indicating extremely low levels of noise of the glider turbulence observations. Criteria have been developed to evaluate the turbulence influence on droplet dynamics in case of a spill. Based on the turbulent velocity scale, for oil droplets with rising speed greater than 10 -2 m s -1 , the turbulence effect can be ignored. For oil droplets with rising speed less than 10 -4 m s -1 , their motion will be affected by the turbulent flow at all depths. For oil droplets with rising speed between 10 -4 and 10 -2 m s -1 , their influence by turbulence is dependent on the strength of local turbulence and water stratification. The enhanced turbulent layers shown in this study are expected to have larger impact on the oil droplet motions when encountered by the oil/gas mixture/hydrate droplets during an oil spill.
