2015/09/24 by Moon, Woosok, Wettlaufer, John S.
#Atmospheric and Oceanic Physics (physics.ao-ph) #FOS: Physical sciences
paper · doi:10.48550/arxiv.1509.07735
We analyze the numerical solutions of a stochastic Arctic sea ice model with multiplicative noise over a wide range of external heat-fluxes, ΔF0, which correspond to greenhouse gas forcing. When the noise is multiplicative, the noise-magnitude depends on the state-variable, and this will influence the statistical moments in a manner that differs from the additive case, which we analyzed in Part I of this study. The state variable describing the deterministic backbone of our model is the energy, E(t), contained in the ice or the ocean and for a thorough comparison and contrast we choose the simplest form of multiplicative noise σE(t) ξ(t), where σ is the noise amplitude and ξ(t) is the noise process. The case of constant additive noise (CA) we write as σESξ(t), in which ES is the seasonally averaged value of the periodic deterministic steady-state solution ES(t), or the deterministic seasonal cycle. We then treat the case of seasonally-varying additive noise (SVA), σES(t) ξ(t), as well as two types of multiplicative noise that depend on the form of stochastic calculus (Itô or Stratonovich) used to interpret the noise itself. The comparison of these four cases reveals the stochastic anatomy of the system over the entire range of the ΔF0 from the perennial ice states to near the ice-free state.