Journal of Natural Disaster Science

ANALYSIS OF TYPHOON PRESSURE PATTERNS OVER JAPANESE ISLANDS (II)

Yasushi MITSUTA
Professor, Disaster Prevention Research Institute, Kyoto University, Kyoto
and
Takeshi FUJII
Professor, Department of General Culture, Kyoto Sangyo University, Kyoto

(Received 8 Aug., 1986 and in revised form 8 Jan., 1987)

Abstract

Statistical data for severe typhoons that struck Japanese Main Islands between 1951 and 1978 were analyzed in a previous study. The present paper is a continuation of that study based on the same analysis techniques for the next six years from 1979 to 1984. The analysis was made objectively to obtain the position of typhoon pressure center, the central pressure depth, the radius of maximum cyclostrophic wind and the direction and speed of translation from hourly routine weather observation data of JMA.

Combining the present results with previous studies, 49 typhoons, with central pressure below 980 mb at the time of landing, could be analyzed. The statistical analysis was made again for all of these data, in which the main islands of Japan was divided into three parts because typhoons that struck the western part of Japan are significantly different from those that struck the eastern part.

Time changes in the parameters after landing and cross correlations of these parameters were also studied. The central pressure depth decreases exponetially with time over land, whereas, the radius of maximum wind and the direction and speed of movement do not vary over the islands from practical point of view. The radius of the maximum wind, however, is dependent on the central pressure depth.

The statistical properties reported here will be used for the purpose of typhoon simulations in disaster prevention works.

Key words

typhoon, objective analysis, Japanese Islands, pressure pattern