Nonequilibrium statistical mechanics of climate variability

The variability of climate features has significant human impacts but

is difficult to model and predict. Recent theoretical developments in

nonequilibrium statistical mechanics cover a class of simple stochastic

models that are often used for climate phenomena. The theory for a specific

coarse-grained entropy production is

developed for simple stochastic climate models and applied to observed

tropical sea surface temperatures (SST). The results show that

tropical SST variability is approximately consistent with fluctuations about a

nonequilibrium steady-state. The presence of fluctuations with

negative entropy production indicates that tropical

SST dynamics can, on a seasonal timescale, be considered as small and

fast in a thermodynamic sense. This work demonstrates that

nonequilibrium statistical mechanics can address climate-scale

phenomena and suggests that other climate phenomena could be similarly

addressed by nonequilibrium statistical mechanics.