Sack Lunch Seminar (SLS)

On (a) An interior sub-mesoscale route to dissipation in the ocean; (b) Some aspects of ocean heat sequestration

Abstract: The first topic considers scales from a few tens of meters to a few tens of kilometers and grapples with a fundamental question that concerns energetics of ocean circulation: how does ocean circulation equilibrate in the presence of continuous large-scale forcing and a
tendency of geostrophic turbulence to confine energy to large and intermediate scales. In particular, interior submesoscale instabilities are shown to provide an interior energy pathway between the largely-balanced, energetic oceanic mesoscales and smaller unbalanced scales with attendant interior mixing (J. Fluid Mech. (2014), vol. 756, pp. 965–1006; doi:10.1017/jfm.2014.464).

The second topic considers global warming from an energy balance perspective. With the global ocean sequestering in excess of 90% of the recent warming due to energy imbalance at the top of the atmosphere, some characteristics of the sequestration are studied in a probabilistic fashion. In particular, it is shown that sequestration of heat above 700m by subduction driven mode water formation processes alone are unable to explain ocean heat observations; sequestration by subduction to greater depths and by some deep water formation processes are necessary to explain them.