Climatological studies of cloudiness

The influence of subresolution clouds on estimates of synoptic-scale averages and the effect of synoptic-scale clouds on estimates of planetary scale interannual variability are discussed. It is shown that climatic noise is strongly dependent on the season and geographic region, so that the largest anomaly is not always the most significant. The role of advection in determining the time-scales and degrees of freedom of synoptic scale cloudiness is empirically demonstrated and described in terms of a simple model of stochastic 'cloud patches'.