Evaluating the influence of traditional land allotment in the historical district of Japanese regional urban center upon outdoor summer thermal environment

Abstract

In Japan, hot summer nights caused by urban heat island phenomena are affecting the health of the elderly population in many regional urban centers. Kumamoto city is one of the major regional urban centers in Japan, and urban heat island phenomena have serious implications especially in summer. Furumachi district is located in the center of Kumamoto city, and regarded as a historical district where many early modern houses have existed. The land allotment of city blocks in this district has not changed since the end of the early modern period in Japan (around 1868), and all new developments are performed as per this traditional land allotment. In the present study, for the effective utilization of the traditional land allotment in the historical district, summer thermal environment in Furumachi district has been analyzed and evaluated both from field measurements and numerical simulations. As a result, it has been demonstrated that the ground cover and spatial structure in and around vacant lands in the district, which have performed under the preserved traditional land allotment, have a significant influence on the sensible heat flux in building scale, and outdoor thermal comfort in living area scale.