Analysis of regional characteristics of the atmospheric heat balance in the Tokyo metropolitan area in summer

The heat island phenomenon in the Tokyo metropolitan area has spread ever more widely, and it is now too wide to treat as a single regional phenomenon. In this paper, the authors have analyzed the climate on an urban scale in summer, and compared the regional characteristics of the atmospheric heat balance at the center of Tokyo, an inland satellite city, and a satellite city on the other side of Tokyo Bay, using a computational fluid dynamics (CFD) simulation. From the results of the analysis, the authors quantitatively demonstrate the mechanism of diurnal change in air temperature and absolute humidity in these areas, focusing on the heat balance. While the sea breeze prevents the air temperature from increasing in the center of Tokyo, it is less effective as a heat sink in leeward areas, such as the inland satellite city. At the satellite city on the other side of Tokyo Bay, the horizontal wind has some influence on the climate. Additionally, the authors tried to classify the regional characteristic of air temperatures by average air temperature and diurnal range.