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The spatial and temporal variability of various cloud types and cloud optical thickness are investigated using daily global analyses produced by the International Satellite Cloud Climatology Project (ISCCP) for the 1983–90 period. The climatological patterns of the relative abundance of individual cloud types are closely related to prevalent circulation regimes. Composite charts at various time lags relative to selected cloudy episodes are used to describe the representative shape and propagation of the local cloud patterns. These satellite-based findings are consistent with published results obtained from analyses of geopotential height and wind data. The midlatitude baroclinic cyclones along the wintertime storm tracks over the North and South Atlantic, and the summertime synoptic-scale disturbances occurring over the tropical western Pacific, are selected for more in-depth investigation. The variations of different cloud types in the selected sites are examined in conjunction with the concurrent three-dimensional atmospheric structure and dynamical processes, as deduced from the daily operational analyses generated at the European Centre for Medium-Range Weather Forecasts (ECMWF). Results for the extratropical storm track regions are in agreement with traditional conceptual frameworks for the organization of cloud properties near warm and cold frontal zones. These midlatitude cloud patterns are linked to the vertical circulation induced by the advection of temperature and vorticity in developing baroclinic waves. Results for the tropical western Pacific reveal cloud structures similar to those occurring in squall lines, with low-top clouds in advance of the approaching deep convection zone, and high-top, optically thinner cloud elements in the rear anvil region. The spatial correspondence between composite features obtained from the independent ISCCP and ECMWF analyses lends credence to the reliability of both datasets, especially in regions with sparse in situ observations. The consistency of the ISCCP cloud patterns with the ambient atmospheric structure and dynamics demonstrates the applicability of satellite data products in advancing our understanding of different types of circulation systems.
Lau et al. (Sat,) studied this question.