OBSERVATIONS OF TILTING MEDDIES

SOFAR floats at different depths within two Mediterranean Water eddies (meddles) reveal that the meddy rotation axes tilt transversely with respect to the meddy translation direction. The rotation axis of one o f the meddles (Meddy 1) was displaced by about 6 km over a depth of ro ughly 100 m; the axis of the second meddy (Meddy 2) was displaced by a bout 0.4 km over 100-m depth. These results are compared to a simple t heoretical model that predicts the deformation and translation of a le ns-shaped eddy embedded in large-scale external shear. Observed latera l deformations of the meddles are in good agreement with model predict ions. The observed tilt of Meddy 1 is attributed to a combination of d epth-varying rotation rate beneath the meddy core and the horizontal t ranslation of the meddy; the tilt of Meddy 2 is attributed to a deform ation of the meddy core by vertically sheared flow outside the meddy. The observed translation speed of the meddles with respect to nearby f loats outside of the meddles is significantly larger than that predict ed by the model.