Assimilation of Sea Surface Height Data into an Isopycnic Ocean Model

Abstract

Abstract Two different methods for assimilating sea surface height data into an isopycnic primitive equation model were developed and tested for the idealized case of an analytical Gaussian warm core (anticyclonic) eddy, then implemented using remotely sensed data from the Brazil–Malvinas confluence region. The first method makes a geostrophic assumption about the flow to relate sea surface height field gradients to the model velocities. The second method nudges the model sea surface height itself toward the observed values using a linear vertical influence function in the upper layers. The relationship between the surface height observations and the layer interface displacements is derived from observations of eddies in different regions of the Atlantic Ocean. Both assimilation methods were successful in transferring the dynamical influence of the sea surface height measurements deep into the water column, but a combination of both gave the best results. The application of both methods reproduced the det...