古日記による小氷期の気候復元に関する年輪気候学的研究
1993 年 102 巻 2 号 p. 119-124
詳細
1993 年 102 巻 2 号 p. 119-124
Informations on the cold weather and climatic disasters during part of the Little Ice Age for 17th to 18th Century in Japan were obtained from tree ring widths and some kinds of historical documents.
Tree rings were analyzed both at Northeastern Japan (Fukushima Pref.) and Southwestern Japan (Okayama Pref.) mostly in Shinto Shrines' precincts. The daily weather records described in old personal documents such as diaries were inquired into at Hirosaki City (Aomori Pref.) for Fukushima's tree rings and at Tsuyama City (Okayama Pref.) for Okayama's tree rings. In this study, the snowy days' rate is used as an indicator of winter coldness. It is defined as the percentage of the number of days with snowfall to that with precipitation, that is, the total of rainy and snowy days.
As a result, it could be concluded that the tree ring widths are narrower in the year of larger snowy days' rate. In Southwestern Japan, it is also considered that the drought summer as well as coldest winter caused the worse growth of trees.
