Michio Aoyama

Michio Aoyama

Dr. Michio Aoyama is since 1995 a Senior Scientist at the Geochemical Research Department of the Meteorological Research Institute in Tsukuba (Japan). He is well known mainly for his work on the distribution of 137Cs in the world ocean. He re-evaluated the total amount of global fallout radionuclides, and estimated that about 790 PBq of 137Cs was deposited as over the Northern Hemisphere, which is 1.4 times higher than the UNSCEAR's global estimate (545 PBq). He has also been working on reference materials of nutrients in seawater (RMNS), and changes of nutrients and biogeochemical parameters in the ocean. He organized four international inter-laboratory comparison studies of RMNS since 2003, and organized several workshops on chemical reference materials in ocean science. His developments in underground gamma-spectrometry analysis of 137Cs in seawater samples helped to decrease the required sample size from 100 to l0 liters. He also developed a marine radioactivity database (HAM) on anthropogenic radionuclides in the world ocean. The HAM database now also includes global and local radionuclide data associated with the Fukushima accident. He published over 100 papers in recognized scientific journals. He recently conducted more than 20 oceanographic cruises to study 134Cs and 137Cs released from the Fukushima Dai-ichi NPP accident in the North Pacific Ocean. He published over 10 papers discussing the temporal and spatial distribution of Fukushima radionuclides from coastal region to the whole North Pacific Ocean.

Affiliations and Expertise

Meteorological Research Institute, Tsukuba, Japan