Changes in Temperatures in Okayama Area Compared with Different Urbanization Areas, Japan

To investigate the changes in temperatures in Okayama area compared with different levels of three urbanization areas such as Tsuyama, Tokyo areas and Hachijo island in Japan. Data of temperatures in Okayama (1891-2009), Tsuyama (1943-2009), Tokyo areas (1876-2009) and Hachijo Island (1907-2009) in Japan was obtained from Japan Meteorological Agency. Changes in temperatures in 4 areas in Japan were analyzed and compared. By using data from 1943 to 2009, some parameters of temperatures were significantly correlated with years. The change in parameters of temperatures in Hachijo Island was calmest among 4 areas. The changes in mean temperature in August and in a year in Okayama area for 50 years were the highest (August: 1.55 ̊C, Year: 2.05 ̊C) among 4 areas. In addition, correlation coefficient rate between years and the number of days over 35 ̊C in August in Okayama area was highest (r = 0.407, p = 0.0037). Parameters of temperatures were gradually increased with years in Okayama area, especially in recent years. However, those associations were not clearly noted in Hachijo Island. In conclusion, global warming in Okayama might be accelerated more rapidly than that in Tokyo area in recent 50 years.