Principal axes for both the hour-averaged and low-passed currents were computed by year and month. Major and minor axes, orientation, and ellipticity were computed from the east (u) and north (v) current components as:

major axis = {[0.5 (UU + VV) + R] / n}^(1/2)
minor axis = {[0.5 (UU + VV) - R] / n}^(1/2)
orientation = 90° - 0.5 tan^-1 [2 UV / (UU - VV)]
ellipticity = 1 - (minor axis / major axis)

where

UV = Sum(u*v) - n U V
UU = Sum(u*u) - n U U
VV= Sum(v*v) - n V V
R = [ (0.5 (UU - VV) )² + (UV)² ]^(1/2)

and U and V are the means of the east and north velocity components, respectively, and n is the number of points in the data series. The orientation is measured clockwise from true north. 0 degress is true north, and 90 degrees is east.

* = Point Current Meter

*Table containing a list of the depth of the deepest ADCP bin for each deployment.

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