Posted by Olaf Boebel on May 17, 2001 at 00:35:23:
In Reply to: Re: BMC floats posted by Alberto Piola on May 16, 2001 at 08:47:08:
Dear Alberto,
this seems to be indeed the case. The comparison of float and MODAS derived velocities, as carried on out in my poster or the ARC, is very promising. In fact, I believe to have pinned down a 5-10 cm/s barotropic mismatch between the zonal velocities from MODAS and those measured by floats. Probability a similar comparison for the BMC, using MODAS or Micom data could help constrain the errors on the transport estimates further and establish a greater certainty in the interpretation of individual features depicted by these data sets.
WRT to chances to observe cross-frontal exchange from drifters you might indeed have a point in that they are less likely to be captured by drifters. Cross frontal exchanges as are probably associated with strong vertical motions when the subantarctic water submerges below the subtropical water. At least this is what our float show. A surface drifter would not be able to follow this vertical component, and hence could be trapped on the subantarctic side of the front. There could also be a bias, in that drifter crossings from the subtropical side to the subantarctic side can occur, while the other direction is inhibited due to the process described in the preceding sentence. I cannot substantiate these ideas, though, but wouldn't that be a nice hypothesis to test: Fronts acting as diodes for surface drifter?
Cheers, Olaf