(7) Partiele cise. Aa stated before, the hodographe (wind
vector diagrans) were crave: normalised te 5,000 feet per hour rate of fall,
i.e one hour wind vectors were draw: for ead §,000 feet increnert of
altitude, end vectors for increments of lese than, ce more than 5,000 feet,
were dravay vith a length proportional to the ratio of the increment heigit
to §,000 feet. This amounted to eonsidering the fall of particles of
approximately 100 microns in ddaneter. Using the normalised hedograp,
direct time and distante measurements could them be made in terme of 100
micron particles, and consideration made for any smaller sised particles
by takingthe distances doubled, tripled, etc, Pricr to BW.VO it ws
asgumed that particle sf{ses dow to 70 wicreris. should be considered; this
anountet! to-douBling the distances taken directly from the normalised
hodographt. After BRAVO, partiste eises dom to 90 microns were considered
to be stgnificant and appropriate adjustaents were made in the fall-out
pattern,
/
(8)
Diffusion.
Prior to C..STLE the accepted factor applied
to the constructiontf fall-out RADEXES to acvcunt for widening of the con=
taminated aiwi wit! distancewas the addition of
ten degree sector on eact
side of tre REE Por CLSTLE, this‘factor wesarbitrarily assumed
“to be fifteen ‘Gegrese. Sines so little we knoves aboutsthe fall-out
neehenion of righ yield eventes,: ant becauée of errorsexisting in other
parameters of the fall-out foresast, it was aseuned that some additional
faster of Saftywasnecessary, even though the value of the factor could
not be preeiselydetermined.