YIELD OF THE HIROSHIMA BOMB DERIVED FROM PRESSURE RECORD,

The microphone gauge air pressure record made from telemetered signals from a parachuted canister near bomber altitude provides a time history of the passage of the air blast and an opportunity to measure the yield of the Hiroshima nuclear explosion. Previous estimates were made without benefit of more recent blast measurements on which to base the calculations. They may, however, have been made with more precise knowledge of the gauge altitude and slant range and of the air temperatures and winds existing at the time of burst. A best guess on the basis of the data and analysis used in these present notes appears to be 14 3 KT, which compares well with the previous blast yield estimate of 18.5 5 KT and a radiochemical yield of 13 2 KT. Author