http://arxiv.org/abs/1808.05098
The Earth is well-known to be, in the current astronomical configuration, in a regime where two asymptotic states can be realised. The warm state we live in is in competition with the ice-covered snowball state. The bistability exists as a result of the positive ice-albedo feedback. In a previous investigation performed on a intermediate complexity climate model we have identified the edge states (Melancholia states) separating the co-existing climates, and studied their dynamic and geometrical properties. The Melancholia states are ice-covered up to the mid-latitudes, are unstable, but attract trajectories initialised on the basins boundary. In this paper, we study the effect of the natural variability of a solar irradiance on the stability of the climate by stochastically perturbing the parameter controlling the intensity of the incoming solar radiation. We detect transitions between the warm and the snowball state and analyse in detail the properties of the noise-induced escapes from the corresponding basins of attraction. We construct the most probable paths for the transitions and find evidence that the Melancholia states act as gateways, similarly to saddle points in an energy landscape.
V. Lucarini and T. Bodai
Thu, 16 Aug 18
7/46
Comments: 5 pages, 4 figures
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