Abstract
Internal structure and time evolution of a cloud cluster in the ITCZ of the western tropical Pacific which appeared on 8-9 June 1990 was analyzed by using meteorological radar data on board of the Keifu Maru, a research vessel of Japan Meteorological Agency. The radar observed the cloud cluster throughout almost all its life cycle. The horizontal size of the cloud cluster was about 500km in diameter and its life time was about 15 hours. The cloud cluster in the mature stage was shown to be composed of four sub-systems of echoes in different stages of development, with earlier stages on the windward side of the low-level wind. The life time of each sub-system was found to be about 8-10 hours. Development and motion of this cloud cluster was characterized by the succesive formation and development of these sub-systems on the windward side of the low level inflow. A schematic model of this cloud cluster is proposed.
