# Transitions between Metastable States in a Simplified Model for the Thermohaline Circulation under Random Fluctuations

## TL;DR

This paper investigates how non-Gaussian Levy noise influences transitions between stable states in a simplified thermohaline circulation model, revealing that small noise can weaken circulation and larger noise accelerates this process.

## Contribution

It introduces a novel analysis of non-Gaussian Levy noise effects on metastable state transitions in a thermohaline circulation model, using maximal likely pathways.

## Key findings

- Small noise can weaken THC within a certain stability index range.
- Larger noise intensity shortens the bifurcation time for weakened THC.
- Non-Gaussian Levy noise significantly impacts transition dynamics in the model.

## Abstract

In this work, we study the impact of non-Gaussian alpha-stable Levy motion on transitions between metastable equilibrium states (or attractors) in a stochastic Stommel two-box model for thermohaline circulation (THC). By maximizing the probability density of the solution process associated with a nonlocal Fokker-Planck equation, we compute maximal likely pathways and identify corresponding maximal likely stable equilibrium states. Our numerical results indicate weakened THC may be induced by perturbation with very small noise intensity in a certain range of stability index. Moreover, larger noise intensity and larger stability index induce weakened THC within shorter bifurcation time.