Increasing Summer Night Temperatures during a 24-Year Periods in Japan:Implications for Rice Production

摘要

Summer night temperatures are increasing across most of the globe. In this study, we attempted to detect variability in recent increasing trends in summer night temperatures in Japan. Hourly night temperatures higher than 25°C and 30°C measured by the Automated Meteorological Data Acquisition System (AMeDAS) of the Japan Meteorological Agency were accumulated for each night during each of six approximately 10 day periods during July and August from 1979 to 2002. These two parameters, called ANT25 and ANT30,were used for our analyses. Although increasing trends in night temperature were conspicuous in large cities such as Tokyo, Osaka, and Nagoya, they were also observed widely throughout Japan, including small cities and rural areas. The highest rates of increase in ANT25 were found in early August from Kanto and Hokuriku districts and to the west along the coast. The effects of night warming on rice production in Japan are discussed