Volume 90, Issue C2 p. 3173-3183
Regular Section

On vertical motion, divergence, and the thermal wind balance in cold-dome meanders: A diagnostic study

First published: 20 March 1985
Citations: 16

Abstract

Wavelike meanders are observed along the length of the Florida Current from the Florida Keys to Cape Hatteras. These propagating meanders are three-dimensional; each has a cold dome; and the meandering flow that overtakes the dome in a cyclonic turn is characteristically stronger when flowing offshore than when flowing onshore. We focus on vertical motion as a key to understanding the interdependence of the downstream propagation, the upwelling in the cold dome, and the skewness in the strength of the meandering flow. Inferred from a composite of drogue and temperature observations, the pattern of vertical motion is one of upwelling that extends throughout the water column formed by the forepart of the translating dome and its overlying on shore flow and a downwelling that similarly extends vertically through the rear part of the dome and its overlying offshore flow. It is shown that the vertical motion and the translation of the meander are interrelated, and both enter importantly in the acceleration of the water columns and hence in the skewness in the strength of the meandering flow component. As the thermal wind changes with the divergence accompanying the vertical motion, it also provides a twisting mechanism to help restore the thermal wind balance.