秋田市における積雪極値の時系列変動解析

概要

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The objective of this study is to clarify the time series characteristics on the maximum depth of snow cover (Smax) at Akita city located in the northwest of Japan, from view-points of periodic variation and winter climatic variation. For this purpose, mehtod of moving average, correlogram analysis, Fourier analysis, cross-correlation analysis, and probability analysis by Gumbel method were applied. On the basis of these analyses, numerical evaluations were made for the secular variation of past 90 years record on Smax. (1) The long-periodic variation on Smax was found by Fourier analysis. It seems to be significant as an indicator of the trend of winter climatic variation in the sense of statistics. (2) The present time Now is presumed as a transitional age in progress of warm winter to cold winter. (3) There are upward type and downward type between the peaks of Smax in similar intervals. The latter one tends to appear in recent years. This penomenon is probable in response to the general fluctuation of the amount of annual sunspot numbers. (4) The basic periodicity of 11 years in heavy snow fall is discerned by correlogram analysis. (5) The amount of Smax accompanied by this periodicity is estimated about 80 cm larger, according to the probability of Gumbel method.
社団法人日本雪氷学会の論文