Abstract
In the former numerical simulation, every one of seven mega-cities showed the warming (Tsfc) of around 1.1 K/Century in calm and clear days of the hottest season, in spite of diversity of the urbanizing stage and the observed subsurface temperature profile. Because city center of each mega-city was already urbanized at the beginning of the 20th Century. However, computing results in consideration of seasonal climate variability (e.g. emerging ratio of each weather type in each season) gave the reasonable differences between Bangkok (0.9 K/Century) and Tokyo (1.9 K/Century). The difference of annual climatic variability is an important factor for deciding urban subsurface warming.
