EN ‘me asheYT SF2G2057) Reppes2pern. ow -' Charles I. Brome, J-1l October 22, 1959 411344 Paul R. Guthals, J-11 PISONIA WEATHER AND ITS EFFECTS ON AIR SAMPLES J-11 As a result of a close investigation of the weather, atmospheric conditions and mean fall rates for this shot, I can make some rather positive statements about the samples collected. During the sampling period, rain was reported to have been falling throughout the sampling area from 20K ft. down. This rain, however, would not have contributed to fallout in the san ples in question. There were thunder storms in the area which topped out above SOK ft. with the possibility of some falling snow and ice. Due to the storms and bomb cloud relative locations, this also does not look as if it could have contributed much in the way offallout. A very likely anawer is that the winds at the higher levels were such that, coupled with the mean fallout rate of 10K ft. per hour allowed some of the debris from the 0-50K ft. levels to be at 30-LOK ft. altitudes in the area where the sampling was done. I have also interrogated the crew of the aircraft which ccllected the questionable sample; since the weather was so bad on this particular day, they were able to recall this shot quite clearly. Their account of the sampling sortie substantiated my own recollection of the event in that they did not sample in a rain cloud but that much of the balance of the bomb cloud was partially obscured in thunder storm clouds. The portion of the cloud in which they sampled was indeed very thin and well diepersed as evidenced by the low radiation intensities which were observed and recorded. Ali of this seems to lend support to the statements made earlier that indeed this sample was contaminated with fallout from the 0-SOK ft. or even higher portions of the cloud. BEST COPY AVAILABLE Paul R. Guthals PRG:¢3 CC P.R. Guthals, J-12 This material contains information affecting a: . the evioasi defense of the United gues EXPARTMENT OF ENERGY DECLASSIFICATION AE\AELY 1ST REVIEWDATE: 0 B-ho- Fe DETERMINATION {CRCL? NUMIBER(S)] WRC ADC CALS, 4. CLASSIFICATION REI MINEO Noun 2. CLASSIFICATION Ci CLD TO: t B.CONTAINS NO DOE CLASSHIED APO “O gd ~ -DATE: 2ND REVIEW GSIDINATE UAcal: AJTHORITY-ADD AUTHORITY: CN wcanion CaneCO . > UX IED INFO BRACKET namesheaton) 7.Mia SPECIPY): ft win the meaning of th Tile 18 U. 8. Bele . ° — Ss and 7)", \ue ‘wiatiog of which in any 73 the risect pers i oF cnautho On 1S Proetl by law “oo .

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