STOCHASTIC DYNAMICS OF BAROCLINIC WAVES

The maintenance of variance and attendant heat flux in linear, forced, dissipative baroclinic shear flows subject to stochastic excitation i s examined. The baroclinic problem is intrinsically nonnormal and its stochastic dynamics is found to differ significantly from the more fam iliar stochastic dynamics of normal systems. When the shear is suffici ently great in comparison to dissipative effects, stochastic excitatio n supports highly enhanced variance levels in these nonnormal systems compared to variance levels supported by the same forcing and dissipat ion in related normal systems. The eddy variance and associated heat f lux are found to arise in response to transient amplification of a sub set of forcing functions that obtain energy from the mean flow and pro ject this energy on a distinct subset of response functions (EOFs) tha t are in turn distinct from the set of normal modes of the system. A m ethod for obtaining the dominant forcing and response functions as wel l as the distribution of heat flux for a given flow is described.