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Turbulence and high‐frequency variability in a deep gravity current outflow
Author(s) -
Nash Jonathan D.,
Peters Hartmut,
Kelly Samuel M.,
Pelegrí Josep L.,
Emelianov Mikhail,
Gasser Marc
Publication year - 2012
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2012gl052899
Subject(s) - outflow , entrainment (biomusicology) , turbulence , gravity current , dissipation , geology , current (fluid) , internal wave , amplitude , mixing (physics) , mean flow , flow (mathematics) , geophysics , mechanics , physics , oceanography , quantum mechanics , rhythm , acoustics , thermodynamics
Intensive sampling of the deep Mediterranean outflow 70 km W of the Strait of Gibraltar reveals a strong, tidally modulated gravity current embedded with large‐amplitude oscillations and energetic turbulence. The flow appears to be hydraulically controlled at a small topographic constriction, with turbulence and internal waves varying together and increasing dramatically downstream of the choke point. These data suggest that a significant fraction of energy dissipation, mixing, and entrainment stress in gravity currents may occur in localized regions controlled by time‐varying flow interactions with fine‐scale topography. These findings highlight the important role of processes that are not resolved by global climate models (GCMs), which do not contain tides or mixing due to fine‐scale topographic interactions.