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IWISE: results


The first figure below shows energy fluxes calculated from LADCP/CTD stations occupied during the pilot cruise (summer 2010), and the two moorings deployed during the cruise.  Observed fluxes are shown in yellow, while the green arrows are from a numerical model (Harper Simmons, UAF).  The observe fluxes generally agree well with model predictions. 

Along the southern line, the diurnal component of energy flux is larger than the semi-diurnal component.  Energy fluxes in both frequency bands are directed towards the NW.

Along the northern line, the semi-diurnal component of flux is larger than the diurnal component.  To the west of the western ridge, energy fluxes are strong and directed towards the west.  Between the ridges, the situation is much more complicated.  Fluxes are very small between the ridges, the direction appears to rotate counter-clockwise around the center of the northern line.

A different view of the situation is shown in the next figure, where the measurements are shown in cross-section along the two lines.  The top panels show the northern line, the bottom the southern line.  The left side shows the diurnal frequency band, and the right side shows the semi-diurnal frequency.

The interference pattern along the northern line  is illustrated clearly in the top right panel.  In the center of the basin, large energy (light gray) is observed, but energy flux (dark gray) is small.  It can also be seen that energy fluxes increase west of the western ridge.  This pattern occurs because the western ridge generates signals that propagate east and interfere with the signals from the eastern ridge.  Along the southern line (bottom panels), flux is relatively constant along the line.


Analysis of data from the main experiment (2011)  is underway; so far we have some very interesting preliminary results.
  Moorings deployed at the eastern end of each line measured longer time-series of energy flux (see figure below).  The top panels show measured tidal currents, showing the spring-neap cycle and variable nature of the forcing.  The middle panel shows time-series of depth-integrated energy, for the diurnal (blue) and semi-diurnal (red) frequency bands.  Time-series of energy flux are shown in the bottom panels for the same frequencies.