Periodic Variability of Precipitation Characteristics in the Region of Niigata Prefecture

Abstract

Daily precipitation data observed at six meteorological observatories located in the region of Niigata Prefecture were collected, and the periodic variability of precipitation characteristics was investigated and discussed by applying spectral analysis and the moving average method. It is shown that a periodic variability of about 20 years is present in time series of annual precipitation in Niigata and Murakami located in the coastal region, and is similar for both cold (Dec.-April) and warm (May-Nov.) season precipitation, and that a periodic variability of about 10-30 years for annual precipitation in Takada, Nagaoka and Toukamachi in the heavy snowy region is similar to that of cold season precipitation with the exception of Yuzawa district. It is shown that time series of annual snowfall in Niigata, Murakami and Takada are composed of the components of a periodic variability of 10-15 years, and that the periodic variability of annual snowfall in Nagaoka, Toukamachi and Yuzawa is 30-40 years. It was indicated that a distinctive periodic variability of less than 10 years exists in time series of annual maximum daily precipitation and annual maximum storm total at all locations.