Double-Diffusive Interleaving at the Equator

Abstract

A theory for the observed interleaving of water masses at the equator is presented. Unlike layers at midlatitudes, individual layers are observed to be coherent over horizontal scales of hundreds of kilometers. To allow for the large horizontal scales, the theory extends previous linear stability analyses for double-diffusive interleaving to an equatorial ?-plane. The poleward increase in the Coriolis parameter is found to limit the latitudinal extent of the layers. The latitudinal length scale [O(10 m)] together with the vertical scale [O(10 m)] given by the theory compare well with that observed.