This paper examines the dynamics of large-scale overturning circulations in the tropical atmosphere using an idealized zonally symmetric model on the equatorial b-plane. Under certain simplifications of its coefficients, the elliptic partial differential equation for the transverse circulation can be solved by first performing a vertical transform to obtain a horizontal structure equation, and ...

One of the most important large-scale ocean current systems for Earth's climate is the Atlantic meridional overturning circulation (AMOC). Here we review its stability properties and present new model simulations to study the AMOC's hysteresis response to freshwater perturbations. We employ seven different versions of an Ocean General Circulation Model by using a highly accurate tracer advectio...

A global ocean general circulation model (GCM) with idealized geometry (two basins of equal size, Marotzke and Willebrand, 1991) is coupled to an energy balance atmospheric model with nonlinear parameterizations of meridional atmospheric transports of heat and moisture. With the coupled model that prescribes the atmospheric heat and moisture transports, the North Atlantic meridional mass overtu...

[1] A large ensemble of experiments with an efficient climate model is carried out to examine stability of the oceanic thermohaline circulation (THC) as a function of two key processes that maintain high Atlantic salinities: the ‘‘Atmospheric Bridge’’ by which moisture is exported from the Atlantic to the Pacific; and ‘‘Agulhas Leakage’’ of salty Indian Ocean waters into the Atlantic. We find t...