ソメイヨシノの開花日を指標とした気候環境モニタリング

フラワーリングシートの作成とそれを用いた観測

抄録

It is said that plant phenology such as flowering, coloring and falling of leaves have been changing recently corresponding with climatic changes in urbanized area of Japan. For example, flowering dates of cherry blossoms (Prunus yedoensis) have been getting earlier year-to-year in Japan. It is considered that these phenomena are related to urban heat island including the effects of global warming. Changes in plant phenology may be useful indicators that show climatic changes such as global warming and urban heat island. Therefore, an observation of plant phenology should be an effective method to evaluate regional climatic environment. The method can be used for school education and environmental monitoring by citizens. And in order to apply the observation to monitoring climatic environment, it is necessary to construct the methods which everyone can easily understand and use to observe.
Then the authors created the flowering sheet of Prunus yedoensis, which everyone used easily to observe in close regions. Moreover, in order to prove the effects of the observation by using the flowering sheet, the authors asked Obirin junior and senior high school students to observe the flowering dates of Prunus yedoensis in the Spring of 2005.
As a result, in study area on the whole, the flowering dates are relatively early areas near downtown Tokyo and they are getting later toward suburban areas. It is considered that the flowering dates may be related to large-scale heat island such as the metropolitan area.
It is clarified that the observation by using the flowering sheet is an effective method in evaluating the large scale climatic environment, based on the distribution of flowering dates. On the other hand, in the small scale, because the numbers of observation points are few, it is difficult to evaluate heat islands by differences in the flowering dates within a city. Therefore, it is proved that the created flowering sheet is effective in the observation.