AN OBJECTIVE ANALYSIS OF CLOUD CLUSTER DIMENSIONS AND SPACING IN THE TROPICAL NORTH PACIFIC

Abstract

The scale of cloud clusters occurring in the tropical North Pacific is objectively derived from vidicon data received from the ESSA satellites for July and October 1967 and January and April 1968. Attention is focused on the inter-tropical convergence zone, which is defined to be the 10° latitude strip with greatest average brightness. The predominant width of cloud clusters is found to range from 275 km in winter to 450 km in summer. The most frequent distances separating clusters are 6°–8° and 10°–12° (latitude) without seasonal variation. The results indicate that a grid size suitable for tropical analysis is about half that used by the National Meteorological Center for midlatitude analysis.