Wind‐driven spin‐up in eddy‐resolving ocean models formulated in isopycnic and isobaric coordinates

Abstract

Wind‐driven spin‐up of the four‐layer, quasi‐isopycnic, eddy‐resolving primitive equation model of Bleck and Boudra (1981) is compared with that obtained with a (numerically dissimilar) “pure” isopycnic coordinate model and an isobaric (i.e., quasi‐Cartesian) coordinate model. In particular, the onset of hydrodynamic instabilities in the flow forced by a double‐gyre wind stress pattern is studied. The spin‐up processes associated with the isopycnic and quasi‐isopycnic model are found to be similar, whereas the flow pattern produced by the quasi‐Cartesian model deviates in the direction of Holland's (1978) and Holland and Lin's (1975 a, b ) two‐layer solutions.