Publication Date:
2022-05-26
Description:
Also published as: Journal of Geophysical Research 85 (1980): 469-484
Description:
Three-dimensional structure of the near-bottom density field was observed with a towed yo-yoing profiler
and a fixed current/temperature measuring array on the Hatteras abyssal plain. A great variety of
structures were seen. Immediately above the bottom a well-mixed bottom layer extends vertically 5-60
m, with less than 1 m°C potential temperature change. This mixed layer is often capped by a region of
strong vertical potential temperature gradient, with up to 100-m°C potential temperature change in -10
m. The boundary layer may be uniform for 10 km or exhibit a bottom temperature gradient of up to 20
m°C/ km. Interior layers of nearly constant potential temperature and horizontal extent of 2-100 km
are seen -25% of the time above the bottom mixed layer. When an interior layer is present, the bottom
mixed layer is thinner. On many occasions an interior layer was seen to be horizontally continuous with
the bottom mixed layer, suggesting formation of interior layers by detachment of the bottom mixed layer.
A benthic front was observed. Differential horizontal advection is required to explain the observed structures.
Velocity fluctuations above I cph increase in energy near the bottom, presumably a signature of
turbulence in the mixed layer;these fluctuations are modulated by the passage of structures observed in
the moored record.
Description:
Prepared for the Office of Naval Research under Contract
N00014-76-C-0197; NR 083-400 and for the National Science
Foundation under Grant OCE 76-81190 ,
Keywords:
Hydraulics
;
Ocean bottom
Repository Name:
Woods Hole Open Access Server
Type:
Technical Report
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