Journal of Natural Disaster Science

CASE STUDY OF THE STRUCTURE AND FORMATION OF A HEAVY-RAIN BAND

Takao TAKEDA
Professor, Water Research Institute, Nagoya University, Nagoya

(Received 30 November, 1981 and in revised form 4 January, 1982)

Abstract

A case study was made of the structure and formation of a heavy-rain band, in which most of the rainfall was produced in just four hours and more than 150 mm was concentrated in a narrow area 20 km wide and 80 km long. The following conclusions were reached after analysis in detail of the horizontal distribution of the intensity of the rainfall and PPI radar-echo patterns. The heavy-rain band consisted of seven to eight cumulonimbus clouds aligned at intervals of 30 to 50 km in the direction of the prevailing wind at middle levels and travelling in the same direction. These cumulonimbus clouds formed over a limited area of the Kii Peninsula and produced their most intensive rainfall in the heavyrain band after more than two hours of movement. Formation of the heavy-rain band is discussed based on the results of our analysis.

Key words

heavy-rain band, radar echo, cumulonimbus cloud