Journal of Natural Disaster Science

A SPECTRAL MODEL FOR ANALYSIS OF PERIODICITY IN INTERMITTENT TIME SERIES AND ITS APPLICATION TO TROPICAL STORM DISASTERS

Shigeaki TSUTSUI
Department of Civil Engineering, Faculty of Engineering, University of the Ryukyus l Senbaru, Nishihara, Okinawa, 903-01, Japan

(Received 8 October 1993 and in revised form 27 December 1993)

Abstract

A new spectral model is developed based on the pulse series analysis to deal with a short, intermittent time series such as in storm disasters. The results or model test show that the spectral model can be used for both continuous and intermittent time series of short sample size. The time series of the tropical storm disasters and the annual extreme-values in climatic factors in Okinawa, Japan, were analyzed. The results show that there is a long-term periodicity of about 9 years in the disasters, which is nearly resonant with the periods for the extreme-values of climatic factors. This means that the deaths in the disasters are chiefly caused by strong winds. In past 30 years, however, the period has reduced to the 5.4-7.7 year period.

Key words

disaster spectra, climatic spectra, pulse series, tropical storm disasters, extreme-values, periodicity