Ocean Deoxygenation Conference | Kiel 2018

The equatorial deep jets and the quasi-steady flanking jets are part of the zonal jet system in the equatorial ocean and play a role in setting the equatorial maximum in oxygen that has been known since the Meteor cruises from the 1920’s. Nevertheless, these zonal jets are missing from the models we use for ocean/climate studies, even ocean models with high horizontal resolution. Here we present a new perspective on the dynamics of the equatorial ocean and show, using mooring data and idealized model simulations, that the equatorial deep jets are maintained by the convergence of meridional flux of zonal momentum on the equator associated with intraseasonal waves, analogous to the maintenance of the atmospheric jet stream by mid-latitude storm systems. The main driving mechanism for the quasi-steady flanking jets might be related to the existence of equatorial deep jets producing a zonal flux of zonal momentum thus maintaining a nearly depth independent westward flow at the equator embedded in eastward flow at 2° latitude on both sides of the equator. The implications for modelling the oxygen distribution in the equatorial ocean will be discussed