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DatasetHow variable is mixing efficiency in the abyss?(Woods Hole Oceanographic Institution, 2020-03-02) Ijichi, Takashi ; St. Laurent, Louis C. ; Polzin, Kurt L. ; Toole, John M.This directory contains BBTRE/DoMORE processed data (“all_BBTRE.mat” and “all_DoMORE.mat”) that was used to produce all figures in the above research letter. Each mat file has two structure arrays named “location” and “patch10”. The “location” array includes microstructure profile information used in this study (Table D1). The “patch10” array includes 10-m patch-wise parameter estimates used in this study (Table D2). Note that bulk averaged parameters can be constructed from parameters saved in “patch10” (see the above paper).
ArticleHow variable is mixing efficiency in the abyss?(American Geophysical Union, 2020-03-28) Ijichi, Takashi ; St. Laurent, Louis C. ; Polzin, Kurt L. ; Toole, John M.Mixing efficiency is an important turbulent flow property in fluid dynamics, whose variability potentially affects the large‐scale ocean circulation. However, there are several confusing definitions. Here we compare and contrast patch‐wise versus bulk estimates of mixing efficiency in the abyss by revisiting data from previous extensive field surveys in the Brazil Basin. Observed patch‐wise efficiency is highly variable over a wide range of turbulence intensity. Bulk efficiency is dominated by rare extreme turbulence events. In the case where enhanced near‐bottom turbulence is thought to be driven by breaking of small‐scale internal tides, the estimated bulk efficiency is 20%, close to the conventional value of 17%. On the other hand, where enhanced near‐bottom turbulence appears to be convectively driven by hydraulic overflows, bulk efficiency is suggested to be as large as 45%, which has implications for a further significant role of overflow mixing on deep‐water mass transformation.