£ rom surface zero,
situation weuld be to take winds -aloft
zero the ideal
:
measurements throughoutthe volume traversed by the particles. Correction for space variation of the winds is then necessary, however in
most cases not as significant as is time variation, Most weather net.
works arc net refined enough to allow quantitative correction for these
errors.
.
:
measurements
were made at Bikini, Rongerik and Eniwetok
atollsUpper
everyair
3 br
starting at H-24
hr and continuing until H+24 br for any
2.2.3
.
Vertical Motions
In applying particle falling speeds to the forecasting technique,
it is assumed that the atmosphere has no vertical velocity. Computa.
tions made at the Eniwetok Proving Ground* to 50,000 ft indicated that
Fallout forecasts were made every 3hr starting at H-24 hr,using
the mezsured winds available at the time, This process was continued
up to shot time and from then, on the technique of cornecting for time
variation, was employed every 3 br until the falloct event was complted.
Mee ce
particles to compensate for this parameter. However, in the work at
the test site it was not possibdie to include this effect in the fallout forecasts, Certain anomalies discussed below may be duc to such an effect
vertical mutions
spaceofvariation
fox lack
to correct
It was not
data,
time acd ami
of the
thisfeasible
period because
during
‘
;
3.1
:
were based entirely on measured data ard quartitatively considered
DISCUSSION OF FIELD TEST RESULTS
The forecasting technique described was employed by the fallout
progiam at the Eniwetok Proving Ground to satisfy certain project
requizements. One. project had three ships equipped te collect fallout
and their positions had to be determined for most efficient collection;
another sampled the ocean for fallout; while another made an aerial
survey of the contaminated area, The navigational schedules for these
latter projects were based on the forecast fallout pattern. Operations
were controlled through the Progcam Control Center aboard the Task
Force Command Ship where the forecasts were prepared.
°
”
The meteorological data were received from the weather ship at :
.
Bikini atoll as well as from weather stations at Rongerik atoll and Eniwetox
atoll, Furthermore,all forecasts made hy the Task Force Weather Cen- ,
tral at Eniwetok atoll were usually available aboard the command ship
by facsimile through the ships Weather Station,
E
Seth
=
i
.
q
Metearelogical Center, fear
° ene
ducerion
of CDR Daniel F. Rex, Joint Task Furce Seven,
oe
Harbor, TH.
.
:
.
-12-
.
‘
UNCLASSIFIED,
/
time variation of the wind. No space variation corrections or computed
values of vertical motions wére employed in their cons.ructioa.
:
:
3.
Fallout Plots
The fallout forecasts determined at the weapons test operation
‘
and post shot analysis is being conducted to see whether they are resolved
~
erage of the winds aloft wes a major belp in the fallout forecasting.
'
large cellular vertical motions. in the atmosphere sometimes attained
75-; particle.
of aspeeds
speed
themadefor
settling
thanbe
and greater
equal to
speed:
of the
falling
the
should
correction
“A
time-space
when the vertical motions have been taken into account.
:
.
:
.
. given Cetonation, The frequency of observativus was usually increasea
.ducing the peried from H-6 toH-2 Sr. The altitudes reached on the wind
rons were reinarkably high and gave perhaps the best set of winds -aloft
Measurements to date, The average termicition altitude was approx.
imately $0,969 “t with many runs over 166,000 it. Such excellent cov—
co
be eae wee ee
7
UNCLASSIFIED
os
§
:
ei eg.
:
UNCLASSIFIED
.
4
:
28
co
.
The area of measured failout from skot A is compared with the
forecast fallout plot in Fig, 12. Figures 13, 14, ané 15 are simalar
comparisons for shots B, C, 1nd D. Aithough C ard D were water
surface shots, 1t is evident that the forecasting technique sccceeded in
representing the measured fallout area as well ss it did for the land
surface detonations, A and B,
:
;
;
.
The comparison is excellent for all shots except B and as yet the
discrepancy between the forecast fallout area and that which was rmeas-~
ured is ankuown, There is some indication that Consideration of vertical
motions will have to be made for shot B during che time of fallos: since
computed vertical Motions were significant in magnitude. ; sch analysis
including space variation is being carried our at thas time for all four
detonations and the refined data will be published later.
SUMMAKY
.
.
.
The fallout forecasting technique described in this report was successfully ernployed for both land,surface and ster surface detonations
-13-
UNCLASSIFIED
cee meee de et ANNE Se DNS Se Wee eeeenmNRie Ali Sree one AOE Meet fen oy Loin cnne eee ee
.