Fine Structure of the Thunderstorm on 21 July 1989 in Nagasaki and Its Neighboring Towns

A sever thunderstorm occurred in Nagasaki and its neighboring towns on 21 July 1989 was studied with a special interest in the evolution and fine structure of rain storms. We made a collection of 42 precipitation records in this region, and then analyzed the temporal and spatial vaiations of 10-minute precipitaion. In addition to this primary approach, we made another analysis of five rain-gauges of high resolution for estimating the size and movement of individual convective clouds. The records of an anemometer and a marine rader obtained at Nagasaki University were also combined in this study. The results can be summarized as follows: (1) The thunderstorm consisted of two rain cells, both of which had 10-minute maximums of 20 mm. It can also be inffered that the storm had three cells if more detail observation had been made. (2) The first cell came from the south coast and made a new cell on its north side of about 10 km distance. These cells both moved to the north at first, ane to the northwest thereafter because of the eastery wind in the upper atmosphere. (3) The size of rain cells had a diameter of about 10 km and their life times were one or two hours. The general features of this thunderstorm agree with the typical models already presented by many investigators