Research by Hiroshima City University reveals mushroom cloud reached height of 16 kilometers
Mar. 1, 2010
by Uzaemonnaotsuka Tokai, Staff Writer
Research by a group led by Masashi Baba, a lecturer in the Graduate School of Information Sciences at Hiroshima City University, has revealed the possibility that the mushroom cloud which formed over the city of Hiroshima after the atomic bomb exploded reached a height of about 16 kilometers. This is twice as high as the estimated height used by the City of Hiroshima to date.
Professor Baba, with his team, analyzed a photo of the mushroom cloud that was taken over the Seto Inland Sea by a U.S. military observation plane in the aftermath of the atomic bombing. The group, using a map from 1950, created a computer image of the coastline at the time, placed the image over the photo, and measured the size of the cloud. The group then concluded that the location from which the photo was taken was "at an altitude of 8.68 kilometers, 56 kilometers southeast of the hypocenter." It is said that the team, taking into account the shape of the mushroom cloud, then calculated that the cloud was 16 kilometers in height.
Based on a photo taken from the city of Kure in Hiroshima Prefecture, 40 minutes after the bombing, an expert committee established between 1988 and 1991 by Hiroshima City and Hiroshima Prefecture in order to conduct research on the rainfall area of the black rain in the aftermath of the atomic bombing estimated that "The top of the mushroom cloud was at a height of 8,080 meters and the cloud was about 4,500 meters in transverse diameter."
It is believed that radioactive fallout that had been dispersed by the atomic bomb ascended to the sky with the mushroom cloud, which was formed by a high-temperature air current, and then fell to the ground. If it is confirmed that the mushroom cloud reached a higher altitude than the former estimate, it will raise the possibility that the radioactive fallout fell to a larger area with the black rain. Professor Baba commented, "This data will help expand the Health Examination Special Designated Area, or the heavy rain area, designated by the Japanese government."
Professor Baba will now cooperate on the meteorological simulation that will be conducted by the City of Hiroshima in fiscal 2010 and 2011 in order to grasp the rainfall area of the black rain. He will help advance the research with the use of images and other photos of the mushroom cloud that were shot from the ground and report the final estimate to the city.
(Originally published on February 27, 2010)
Research by a group led by Masashi Baba, a lecturer in the Graduate School of Information Sciences at Hiroshima City University, has revealed the possibility that the mushroom cloud which formed over the city of Hiroshima after the atomic bomb exploded reached a height of about 16 kilometers. This is twice as high as the estimated height used by the City of Hiroshima to date.
Professor Baba, with his team, analyzed a photo of the mushroom cloud that was taken over the Seto Inland Sea by a U.S. military observation plane in the aftermath of the atomic bombing. The group, using a map from 1950, created a computer image of the coastline at the time, placed the image over the photo, and measured the size of the cloud. The group then concluded that the location from which the photo was taken was "at an altitude of 8.68 kilometers, 56 kilometers southeast of the hypocenter." It is said that the team, taking into account the shape of the mushroom cloud, then calculated that the cloud was 16 kilometers in height.
Based on a photo taken from the city of Kure in Hiroshima Prefecture, 40 minutes after the bombing, an expert committee established between 1988 and 1991 by Hiroshima City and Hiroshima Prefecture in order to conduct research on the rainfall area of the black rain in the aftermath of the atomic bombing estimated that "The top of the mushroom cloud was at a height of 8,080 meters and the cloud was about 4,500 meters in transverse diameter."
It is believed that radioactive fallout that had been dispersed by the atomic bomb ascended to the sky with the mushroom cloud, which was formed by a high-temperature air current, and then fell to the ground. If it is confirmed that the mushroom cloud reached a higher altitude than the former estimate, it will raise the possibility that the radioactive fallout fell to a larger area with the black rain. Professor Baba commented, "This data will help expand the Health Examination Special Designated Area, or the heavy rain area, designated by the Japanese government."
Professor Baba will now cooperate on the meteorological simulation that will be conducted by the City of Hiroshima in fiscal 2010 and 2011 in order to grasp the rainfall area of the black rain. He will help advance the research with the use of images and other photos of the mushroom cloud that were shot from the ground and report the final estimate to the city.
(Originally published on February 27, 2010)
