[Stoch] New paper on stochastic climate modelling

[Paul Williams]

Dear all,

I would like to draw your attention to a new stochastic climate modelling paper, published in GRL this week.

Best wishes,
Paul.

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Williams, P. D. (2012), Climatic impacts of stochastic fluctuations in air–sea fluxes, Geophys. Res. Lett., 39, L10705, 
doi:10.1029/2012GL051813.

http://www.agu.org/pubs/crossref/2012/2012GL051813.shtml

Abstract.  Air–sea fluxes vary partly on scales that are too small or fast to be resolved explicitly by global climate 
models. This paper proposes a nonlinear physical mechanism by which stochastic fluctuations in the air–sea buoyancy flux 
may modify the mean climate. The paper then demonstrates the mechanism in climate simulations with a comprehensive 
coupled general circulation model. Significant changes are detected in the time-mean oceanic mixed-layer depth, 
sea-surface temperature, atmospheric Hadley circulation, and net upward water flux at the sea surface. Also, El Niño 
Southern Oscillation (ENSO) variability is significantly increased. The findings demonstrate that noise-induced drift 
and noise-enhanced variability, which are familiar concepts from simple climate models, continue to apply in 
comprehensive climate models with millions of degrees of freedom. The findings also suggest that the lack of 
representation of sub-grid variability in air–sea fluxes may contribute to some of the biases exhibited by contemporary 
climate models.