Multiplicative noise in atmospheric dynamics: Modeling and observations

Philip Sura
Scripps Institute of Oceanography

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Abstract

The role of multiplicative noise in atmospheric models and meteorological data analysis is discussed.

On the one hand the concepts of multiplicative stochastic perturbations and noise-induced transitions are applied to a quasi-geostrophic beta-plane model of barotropic flow over topography. The stochastic representation of the damping term leads to a multiplicative stochastic forcing. It is found that the qualitative behavior of the system is a function of the multiplicative noise level. It is suggested that the statistics of the unresolved physical processes could be an important factor to understand the behavior of mid-latitude large-scale atmospheric dynamics.

On the other hand it is shown that a proper stochastic description of synoptic midlatitude sea surface winds requires a multiplicative noise component. For that purpose a general method is used to estimate the drift and diffusion coefficients of a continuous stationary Markovian system. The results indicate that multiplicative noise terms may be necessary in order to fit stochastic models to reality or more complex models.

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25 Feb, 2002 (Note: special day)
2 PM/ DSRC 1D 403
(Coffee at 1:50 PM)
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