Posted by Ricardo P. Matano on May 08, 2001 at 23:52:16 (UTC):
I greatly enjoyed reading this poster. I am intrigued by the apparent
stability of the ARC path (first figure in the DATA section). The fact
that the RAFOS floats seem to follow so closely the mean flow (as
derived from the MODAS SSH data) seems to indicate that the positions of
the troughs and crest are quasi-stationary. Is this true? What is the
dynamical explanation to these meanders? Are they driven by the bottom
topography or are they Rossby waves arrested by the mean flow?
The Hovmoller diagram of the DYNAMICS section is quite interesting
although I couldn't follow the rationale behind the statement that these
propagating patterns are associated with eddy shedding instead of wave
propagation. Do the authors mean that actual eddies propagate westward?
It seems that the westward speed of a self-propagating eddy is no match
for the strong mean flow derived from the LADCP. Couldn't it be that
the interaction of the ARC with the ridge near 40 E generates westward
propagating waves that -sometimes- trigger eddies?
The westward propagation of cyclones in the Hovmoller diagram seem to
progress well beyond the Agulhas Plateau (is it correct?). I surmise
that the apparent discontinuity over the Agulhas Plateau (~ 25 E) is
caused by a deflection to the north of the mean flow and do not
necessarily mean that the westward propagation stops there. If so: is
there any evidence that the westward propagation of perturbations in the
ARC trigger Agulhas eddies?
Cheers, Ricardo.