風速変動の長周期成分について

Abstract

A power-spectrum analysis of horizontal wind speed is made over a wide range fromabout 107 cps to 2. 5 x 10-1 cps by piecing together various portions of the spectrum.There appear to be three major eddy energy peaks in the spectrum; one peak occurs ata period of 4 days, second peak occurs at a period about 1 day and the third one occursnear a period of 1 mm.Between the later two peaks, there is a broad spectral gap. The power spectraldensity decreases in proportion to the -5/3th power of frequency between 10-5 cps (theperiod is about 1 day) and 10-4 cps (the period is about 3 hours) as well as in the fre-quency range higher than 10-1 cps.