INTERNAL AND EXTERNAL VARIABILITY IN A BAROCLINIC ATMOSPHERE

A simplified global circulation model is used to test a parametrizatio n of the eddy temperature fluxes owing to baroclinic waves based on th e Eady linear theory. The parametrization is shown to give adequate re sults over a wide range of imposed parameters. However, the irregular low-frequency fluctuations of temperature flux and baroclinicity withi n an individual run appear to be largely uncorrelated and therefore un parametrizable in such simple terms. Hence, internal and externally fo rced changes of baroclinic activity have very different signatures in terms of flux-baroclinicity relationships and could be distinguished. (C) 1997 Elsevier Science B.V.