H. Schafer et W. Krauss, EDDY STATISTICS IN THE SOUTH-ATLANTIC AS DERIVED FROM DRIFTERS DROGUED AT 100 M, Journal of marine research, 53(3), 1995, pp. 403-431
More than 130 satellite-tracked buoys drogued at 100 m depth have been
deployed by us in the South Atlantic during the years 1990-1993 in an
ongoing program. After eliminating those portions of the trajectories
for which the drogue was off, Lagrangian eddy statistics are computed
and compared to the results of a similar data set in the North Atlant
ic and to previous results for the South Atlantic. Regarding the relat
ions based on Taylor's theory, no significant differences can be seen
between the North and South Atlantic. The Lagrangian integral time sca
le is inversely proportional to the r.m.s.-velocity which implies that
eddy diffusivity is directly proportional to the r.m.s.-velocity and
not to the variance. Previous studies on that matter are most likely i
nfluenced by buoys which lost their drogue. Eddy length scale is const
ant with values of 37 km in zonal and 28 km in meridional direction, a
veraged over the entire Atlantic. Eddy diffusivity varies between 2.10
(7) and 8.10(7) cm(2)/s, being smallest in the subtropics and highest
in the Circumpolar Current. The proportionality to eddy velocity and a
constant length scale opens the possibility to compute global distrib
utions of eddy diffusivity from altimeter data.