ABSTRACT
This process sometimes fails near sharp headlands and islands, where centers of trajectories may be situated on land. Such trajectories have been eliminated here.
Except for this limited drawback, which it seems quite easy to overcome, the method leads to a unique residual Lagrangian velocity field and preserves most of the information obtained previously. It seems better than a simple averaging of residual Lagrangian drifts (Feng, 1987) which would have eliminated some of the velocity features appearent on fig. 3, such as minima and maxima of bundles of vectors.
