Arctic Eddys from IOEB ADCP Data
Filtered and Earth-referenced ADCP data from the B92, B97
and S97 IOEBs were demodulated to remove inertial and near-inertial tidal
frequencies, in order to highlight the low frequency components for examination
of Arctic submesoscale eddys. Using
the demodulated timeseries of current profiles from each buoy, characteristics
of 95 possible eddy encounters are quantified by (1) identifying anomalously
large velocities associated with subsurface vortices, (2) determining the
vortex centers and their drift, and (3) determining vortex properties as a
function of radius and depth. Out of 44
total months of observations, 81 of the encounters were determined to be
subsurface eddies, and 29 were eddy core encounters. Only 14 of the confirmed subsurface encounters were cyclonic,
versus 66 anticyclonic, and one indeterminate.
Within the southern and central Canadian basin portion of the Beaufort
Gyre, halocline eddys with maximum velocities between 10 and 45 cm/s, centered
around 140 m depth, and over 100 m thick were prevalent. Over the Northwind Ridge, eddy encounters
were absent from any timeseries.
Farther north and west over the Chukchi Cap, encounters resumed, but
were generally smaller, more shallow and less intense (although these
observations were mostly derived from a lower resolution transmitted data
subset).
