Periodic variability of precipitation along the Sea of Japan Coastal Region

摘要

Long-term daily precipitation data covering more than one hundred years at local meteorological observatories on the Sea of Japan coast were divided into warm and cold season precipitation, and the periodic variability of precipitation characteristics was investigated and discussed by applying spectral analysis and the moving average method. For annual precipitation time series, it is shown that a periodic variability of about 20 years is present in Akita and Yamagata located in the Dewa region, and that a periodic variability of 11-13 years is present at Sakai and Hamada located in the San-in region. For Hokuriku region, a periodic variability of about 13 years at Fushiki is similar to that of San-in region, while a periodic variability of about 20 years at Tsuruga is similar to that of Dewa region. It is interesting that the periodic variability of cold season precipitation is the same within each climatic district for all regions, but varies between districts. Additionally a periodic variability of more than 10 years exists in time series of annual maximum daily precipitation.