_
—
Sis
be
>
~~
°
.
v
rope
:
*
_
- kyPoy
:
“
ry
7
‘
,
bee ew
:
:
tee
Clitesifile
Lo
: \
*
ain of
:
¥
ee
Boe
«ow
z
ee
ConerroPNrrAl 0 Aeee
fal Brreg_
0 tu wo het
far O5~6._-
Lhe
77
.
Too
ar ID
ry Ne
a,
-y
Ey oo. b
foo.
-
ott nt
sn
Mor
- we
ee
owe
DL
CLOSE@IN FORSC..STING BY NEV TECHNIQUES DEVELOPED .FTSR Bit..vo
SyHACT FROM ~
Yef Z
-:
7
“nk Kepert
‘
Themas N. White
ALos .lamos Seientifie Laboratory
(edteenCat
ie
Yury
1.
July 195%
f GS4
The method of calculatinz local fall-out, as described here, is
the hasty outcrowth of a more complex method that had been unexpectedly
successful in accounting for the Hu.VO fall-out pattern in the Jilinsinae
Rongelap—nongerik areca.
a
4s the time of the lest shot (on Eniwetok «toll)
approached, the problem of forecastins loeal fall-out bocame more acute.
-
Since the method attempted to take account of the initial size ond share
&
a
n
With the aid of Dr. Geelen Felt, the method was simplified to the extent
that an atoll pattern could be estimated within cbout an hour. The
simplified method was tested egainst the Bikini retterns produced by
e
of the cloud, it seemed that it should be suitable for local forecasting.
2
$
ROMEO, UNION and Y/NKEE and found satisfactory, end the method was used
in forecasting for NECTAR.
2. The following descripticn covers the simplified method only. The
more complex method warrants further study whith will be rerortod clsc-
§.
3.
2
“Assumptions:
ep
(a) The initial cloud (efter riso is practically completed) is
divided into horizontal slices, cach cf 10,000 ft dapth, with cmtcrs at
10,000, 20,000, = = = = 70,000 ft altitude, with the central concentration
& Se
se
(>) In each layer all of the ectivity lies in a horizontal
Plane thru the cantar.
Bee
(radio-activity per unit volume) independent of altitude.
(ec)
In each layer, the concentration fells off laterally
according to the law of normal distribution of errors
c(r) =Coe
F
“~ré
&p2
» Where C, is the initial central concentretion, r is distance fron contar,
aMd a, fs the initial spread parameter (analogous to standard deviation).
For altitudes 10,000 thru 40,000 ft, a, = 1.9 miles; 50,000 thru 70,000 ft,
& = 5.8 miles.
<
~
ANCLOSURE #3)
b-a8
tlA |
USE ASTTELED
£