On the Secular Variation of Bai-u or Rainy Season in Japan

[摘要] Three elements of Bai-u, the amount of precipitation, the number of rainy days, and the center of mass of rainy days were treated graphically for five stations in Japan. 33 years or 22 years periods were found in the secular variation of these elements. The phase of the secular change of the amount of precipitation seems to marchi E-wards or W-wards across Japan for several years. This phenomena seems to suggest the direct cause of the secular variation.

[学科分类] 大气科学