Who were the Hiroshima and Nagasaki bomb Downwinders? What paths did the bomb clouds take?

by nuclearhistory

Who were the Hiroshima and Nagasaki bomb Downwinders? What paths did the bomb clouds take?

Every nuclear weapon detonated in the atmosphere, including Trinity, had it cloud path tracked. At Trinity there was a massive effort to do this (http://www.abebooks.com/Shockwave-Countdown-Hiroshima-Stephen-Walker-HarperCollins/4182182187/bd)

However, all the information on bombs numbers 2 and 3 is limited to denials of substantial fallout over the target (apart from the Black Rain) . Although that in itself is a fudge, as 70s era soil analysis show, the tale the bomb clouds just drifted away from the target cities is unique.

We know that the B29s which delivered the weapons to target were not the only ones in the air after the bombings. (Height Estimation of Hiroshima A-bomb Mushroom Cloud from Photos
city.youth-service.com/03database/0106.pdf
File Format: PDF/Adobe Acrobat – Quick View
by M Baba )

Yet the record, as far as I can find, describes no B29s assigned to tracking the paths of the bombs.

So where did the bomb clouds go? The question was of keen interest to the 1945 Kyoto team who entered Hiroshima a couple of days after the bombing to survey the radiation in the city. Shimizu’s 1982 remembering the Kyoto University Hirohima surveys, which included met data from the Japanese Air Force. “Historical Sketch of the Scientific Field Survey in Hiroshima….” http://repository.kulib.kyoto-u.ac.jp/dspace/handle/2433/76996 ……
He writes: “Three members of the team split off and went to the Iwakuni base of the Navy Air Force to seek information about the atmospheric conditions that were present above Hiroshima on the 6th of August 1945.
The entire party returned to Kyoto with the information and samples on the
16th of August.” (Source: Shimizu’s note 12, page 54 of the Bulletin). So some Japanese scientists were consdiering where the cloud went.

It’s incredible to think that the then enemy found this an important question, while the record written and released, as far as I can find, by the USA makes no mention of it.

Whereas the atomic test era which followed after was dominated by cloud tracking, cloud sampling and fallout path monitolring.

So, does anyone out there know anything about the paths taken by the Hiroshima and Nagasaki bomb clouds?

Every atmospheric nuclear weapon had its Downwinders and bombs numbers 2 and 3 were, I think, no different.

http://www.gwu.edu/~nsarchiv/radiation/dir/mstreet/commeet/meet6/brief6/tab_f/br6f1k.txt

AFSC HISTORICAL PUBLICATION SERIES
61-142-1
HISTORY OF AIR FORCE ATOMIC CLOUD SAMPLING
CONTENTS
VOLUME I
FORWARD . . . . . . . . . . . . . . . . . . . . . . . . . .i
INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . ii
LIST OF CHARTS AND ILLUSTRATIONS. . . . . . . . . . . . . .v
CHRONOLOGY. . . . . . . . . . . . . . . . . . . . . . . viii

I.TESTS PRECEDING MANNED SAMPLING. . . . . . . . . . . . . . . .1
Operation TRINITY. . . . . . . . . . . . . . . . . . .1
Operation CROSSROADS . . . . . . . . . . . . . . . . .3
Sampling CROSSROADS . . . . . . . . . . . . . . .4
Evaluation of CROSSROADS Sampling . . . . . . . 13
etc.

Note the gap between Trinity and Crossroads. Why is the answer apparently still secret?

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