Physics and Dynamics of the Oceans

This chapter focuses on the physics and dynamics of the ocean. It describes the variability of salinity and surface temperature, as well as the vertical temperature structure of the ocean, with the thermocline separating the variable top layer from the deeper ocean. It then describes the key forces in the ocean, as well as the geostrophic balance due to the Coriolis force and density differences. It derives the equations for the change of velocity with depth, the Ekman flow. Barotropic flow and baroclinic flow are elucidated and the general circulation of the ocean, with gyres and the effect of vorticity on their structure, is shown. The thermohaline circulation of the ocean with surface flow and returning deep ocean flows is described. Next, a simple model is used to show how salinity interacts with the thermohaline flow. Finally, as an example of ocean–land interaction, the El Niño phenomenon is described.