On the interpretation of eddy fluxes during a blocking episode.

Abstract

Using twice daily synoptic charts, objectively analyzed at the National Meteorological Centre, horizontal eddy fluxes of temperature and quasi-geostrophic potential vorticity are computed for the month of July 1976, when a blocking anticyclone was centered over western Europe. The local time-averaged eddy variance equations are used to provide a dynamical basis for interpreting the spatial pattern of eddy fluxes, and their relation to mean gradients. It is shown that a rotational non-divergent flux can be identified, the cross-gradient component of which balances the mean flow advection of eddy variance. -from Authors