Michio Aoyama
Geochemical Research Department, Meteorological Research Institute
Noriyuki Kawano
Institute for Peace Science, Hiroshima University
Toshio Koizumi, Takahiro Tanikawa
Architecture and Civil Engineering, Chiba Institute of Technology
Takao Okada
Research Division, Atomic Bomb Survivors Relief Department, Hiroshima City
Yoshihiro Okada
Heiwa-Kensetu Co. Ltd
Megu Ohtaki
Research Institute for Radiation Biology and Medicine, Hiroshima University

Abstract

The amount of flammable materials in traditional Japanese houses in the Hiroshima region in July 1945 was estimated in terms of kg m-2 in each 50 m grid in 8 km x 8 km region. Then, the amount of flammable materials was converted to heat, water, and black carbon fluxes based on the duration of the fire induced by the A-bomb as a function of time and space. The average heat flux in the region was 14.4 kJ s-1 m-2, and it ranged from 0.5 to 96.5 kJ s-1 m-2. The total heat released during the fire was 7 PJ. In total, 0.22 Tg of water was produced and released during the fire. The total amount of black carbon produced and released during the fire was 0.02 Tg, when we assume that 10% of the fuel was under reducing conditions. The time-dependent fluxes of heat, water, and carbon were also calculated in each 50 m grid.