Interdecadal thermohaline oscillations in a sector ocean general circulation model: advective and convective processes

Abstract

Oceanic interdecadal thermohaline oscillations are investigated with a coarse-resolution version of the Geophysical Fluid Dynamics Laboratory Modular Ocean Model. The model ocean is forced by a zonal wind stress, heat flux parameterized by restoring the surface temperature toward a reference value, and a specified surface freshwater flux. Zonal wind stress, reference temperature, and freshwater flux are all longitudinally uniform, time-independent, and vary meridionally. It is shown that the ocean model can be in a state of interdecadal oscillation, and a physical mechanism is explained. For these oscillatory solutions, both surface mean heat flux and basin and kinetic energy vary with interdecadal periods. Temperature and salinity budget analyses reveal that these oscillations depend primarily on advective and convective processes. -from Authors