Resilience of Ocean Circulation to Changes in Temperature and Salinity in a Classical Box Model
Ocean circulation is essential when considering heat absorption and transportation around the globe. Box models have been used to conceptualize the effects of temperature and salinity on the circulation. In a classic 1961 paper, Stommel introduced a two box model to illustrate that ocean circulation could have multiple stable steady states depending on the parameters of temperature and salinity. Changes in these parameters can eliminate one of the steady states, resulting in the system equilibrating at a new steady state. However, when the parameters are returned to their previous values, the system remains in the new state and does not return to its previous state. Whether or not the system switches states depends on the magnitude and duration of the parameter change. In this paper we quantify the boundary between the values of magnitude and duration causing the system to switch states and those values where the system returns to its previous state.