ASCII Data and File Structure

The various data for the tracked eddies are contained in a single ASCII file, which is available for download HERE.
Click HERE for a description of the geographical domain and sample output.

This file contains the following 6 lines in ASCII format for each eddy track:

Line 1:   track, n, j1, cyc
Line 2:   (lon(i),i=1,n)
Line 3:   (lat(i),i=1,n)
Line 4:   (A(i),i=1,n)
Line 5:   (L(i),i=1,n)
Line 6:   (U(i),i=1,n)

The above variables are defined as follows:

track is the eddy identification number.

n is the number of points along the eddy track (separated by intervals of 1 day).

j1 is the julian date of the starting point. (Numerical Recipes provides the routine caldat for converting julian day to month, day, and year, and the routine julian for converting month, day, and year to julian day.) Subsequent points along the trajectory are separated by a time interval of 1 day.

cyc is -1 for cyclonic eddies and +1 for anticyclonic eddies.

lon, lat are the longitude and latitude of the centroid of the eddy at each of the n points along the eddy track. In order to avoid jumps of ~360° in eddy tracks when the trajectory wraps around a longitude branch point that might lie in a region of interest, the longitude domain is set to 260°E-650°E. This range was selected so that the only eddy trajectories that might still be affected will be those passing through the Drake Passage. In latitude, the domain extends from 80°S-80°N.

A is the eddy amplitude, defined to be the magnitude of the height difference between the extremum of SSH within the eddy and the average of SSH over the edge pixels that define the outer perimeter of the eddy.

L is the eddy radius scale, defined to be the radius of a circle with area equal to that enclosed by the contour of SSH within the eddy around which the circum-average speed is maximum.

U is the average speed around the SSH contour that defines the scale L, i.e., the maximum circum-average speed within the eddy.