Analysis of exhaustion characteristics of anthropogenic exhaustion heat considering the differences of sensible and latent heat in Tokyo 23 wards

Abstract

It is considered that the anthropogenic exhaustion heat generated by consuming energy is one of the main causes of the heat island phenomena in cities. In this research, we distinguished between sensible and latent heat, and databased on the GIS over the generation sources of the anthropogenic exhaustion heat in Tokyo 23 wards (buildings, automobiles, factories) and analyzed the exhaustion characteristics of anthropogenic exhaustion heat, concerning space-time, generation source, sensible and latent heat in 500m mesh. The results of this research are as follows. 1) The daily average value of anthropogenic exhaustion heat during the summer in Tokyo 23 wards was 32W/m^2, which equaled to the 18% of the average sun radiation of a day. Also, the daily average amount of sensible anthropogenic exhaustion heat in Tokyo 23 wards was greater than that of the latent heat by 5 times. The large amounts of latent anthropogenic exhaustion heat, over 400-1000W/m^2 per 500m mesh, were generated during the day in places such as Shinjuku and Otemachi, where high-rise buildings were concentrated. 2) When comparing the generation sources of the anthropogenic exhaustion heat, it was found that the anthropogenic exhaustion heat from buildings were concentrated in the center of Tokyo, while anthropogenic exhaustion heat from road traffic expanded toward suburbs, and that of the factories were found around the places locally where factories took place. The distribution of sensible and latent anthropogenic exhaustion heat showed that the meshes with large exhaustion ratio of latent heat were found primarily in the center of Tokyo. Also, the result from comparing anthropogenic exhaustion heat by day and night showed that the anthropogenic exhaustion heat during the day were concentrated in the center of Tokyo. 3) The cluster analysis was operated using the data of anthropogenic exhaustion heat of buildings and road traffic, and the distribution map differentiated by districts in Tokyo 23 wards was made. The three districts were chosen, and the exhaustion characteristics of anthropogenic exhaustion heat during the day were investigated. The results showed that in Shinjuku, anthropogenic exhaustion heat from buildings were occupying the greater part of the anthropogenic exhaustion heat, and more than half of their heat were released by latent heat. The greater part of the anthropogenic exhaustion heat in Setagaya were sensible heat coming from buildings and roads. It was found that the most of the anthropogenic exhaustion heat were composed of sensible heat from buildings during the day in Nihonbashi.