Directional dependence of zonal and meridional wind correlation coefficients

Evidence is presented which suggests that the spatial correlation coefficients of zonal and meridional wind components decay most slowly with increasing separation, in directions that depart slightly from those expected assuming geostrophic flow in a horizontally homogeneous and isotropic atmosphere. The consistency between studies in four different geographical areas indicates that at least a part of the departures may be global in character, but further examination of data from other parts of the world is needed to confirm this.