Journal of Geophysical Research: Oceans

(a-d) Meridional sections of turbulent energy dissipation, epsilon, estimated from vertical microstructure measurements across the southeast Pacific, western Drake Passage, the Phoenix Ridge and the Scotia Sea, respectively. The increased mixing to the east is associated with enhanced current speeds and rougher topography. Results are from the Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean.

(top left) Bathymetric map of the Carambar study area showing seismic and hydrological data positions. The black thick line shows the location of Carambar seismic section #14, acquired on 9–10 November 2010, and the red triangle the XBT station acquired on 5 November 2010. The inset shows the geographic setting of the study region, indicated by the blue dot. (top right) General overview of the processed seismic section #14. Data processing details are outlined in text. The red box denotes the enlarged portion of the profile presented below. (bottom left) Enlarged view of the processed section #14. Reflectors at depths ranging from 52 to 110 m are the signature of an overflow from the neighboring Grand Bahama Bank, which gets thinner further from the bank. The blue arrows indicate the top and the bottom boundaries of the structure. (bottom right) XBT temperature profile (black) and derived reflectivity (red). The dashed blue box indicates the extent of the overflow.

Conceptual illustration of fluid mud formation and entrainment in troughs of subtidal dunes in an estuarine turbidity zone. Stage I, II, and III show the accumulation of suspended sediment and fluid mud formation during slack water. Stage IV is governed by velocity shear. Stage V depicts the transition from the influence of shear to entrainment, which occurs during stage VI. The dune-specific distribution of currents and turbulence in the lee-side is sketched in stage VII, with flow oriented in dune direction. Values of current velocity and suspended sediment concentration correspond to the beginning of each stage. Time is hours after slack water.

Turbulent diffusivity (Kt) calculated from equation () using the best fit parameters given in section 3.1 plotted for Richardson number (Ri) in the range of 0 to 100. Black dashed lines indicate the bootstrapped 90% confidence limits to the fit. Observations of turbulent diffusivity from the three individual data sets used in the derivation of equation () are marked. The dashed red line indicates a constant diffusivity (Kbs) of 8 × 10−6 m2 s−1; the blue dashed line represents the best fit parametrization (equation ()) without the Kbs term.

Total downstream velocity (left) before and (right) after the winter 2007–2008. These conditions are typical of all periods when PC1 is large and positive (mean + EOF1) or large and negative (mean − EOF1).

Global maps of time-averaged zonal geostrophic velocity, u¯, estimated from (a) observed and (b) simulated SSH, 1993–1996. Observed SSH consist of AVISO/CLS ADT and were spatially high-pass-filtered prior to estimating zonal geostrophic velocity. Simulated SSH were obtained by superimposing Gaussian eddies with amplitude, scale, position, and lifetime identically specified by the eddy database [CCS2011] onto an otherwise flat ocean. Black boxes denote the region examined in this study (20°S–50°S, 200°E–280°E).

Climatological cooling inhibition index (CI; in (J.m−2)−1/3) for (a and d) premonsoon and (b and e) postmonsoon seasons, and (c and f) their difference using (top) observations and (bottom) the model over the 1978–2007 period. The thick contour delineates a region where 80% of TCs occur in the northern Indian Ocean (see Figure 1) while dashed colored boxes on Figure 6c are same as in Figure 3. The black dashed line indicates the temperature and salinity section at 90°E shown on Figure 5.