(2) If wind shear is >10° but € 120°, minor axis is 4 of asfor

axis. This is case for 20,000 feet winds to tropopause, and sonewhat less
for 65,000 to 95,000 feet winds.

me ie

‘y

(This is case of 0-5,000 feet winds and 5-20,000 feet winds.)

a oek

looked at).

ent

(1) If wind shear is <10° for the levels in question, ainor

1/8 to 1/4 of the major axis (which is the entire vector for Levels

”

axis is

cp Meh

wert

(3) If shear at levels making up vector under study is >120°

draw circle with diameter = to entire resultant vector.

CONCLUSIONS:
1.

Prom overall fall-out picture, it is concluded that fall-out may

have reached Rongelap Island and Ailinginae later than the pessimistic tine

2e

From initial land survey reports on icngelap Atoll with levels st

Erippa Island (NB part of Atoll) still at 2.8 to 3.5 r/hr on B plus 7 days,

the picture for heaviest fall-out patterns north of this area is estab> ished.
The relatively light fall-out at Utirik (258 of the hot area), hizher levels
of intensity at Bikar (East and downwind of the hot area, i.e..6 r/hr at 2
plus 33 hours almost in downwind line with the superimposed ellipses or hot
areas but definitely beyond the hot shadow), confirm the belief in che ass=ced
area of hot fall-out pattern abova.

Wotho (SSE of the area and fro= Gro-wnd

Zero) received practically nothing because resultant vector wind speed froa
the stem and, perhaps some of the mushroom fringe, was so low in velocity

through the SE to South from Ground Zero, Zminetok received at about EB pics
11 hours a build up to about 10 mr/hr for a period of about ive hours.
3- This type of analysis gives a feeling only for pattern of fall-out
because it does not tell exactly rhen the fall-out errives. Eowever, 4% °
epparent that the 200-200 plus roentgens lifetine dosage line sessed on or
close to ailinginae, Rongelap Island and Rongerik which are at 20-100 alles
in cases of dilinginae and Rongelap and 130 miles to Rongerik froma sreund
Zero. The 1,000 plus roentgens lifetime dosage lines are exceeded as cue goes

north from Rongelap Island to northern islands of that atoll.

Tbis analysis

is based on: (1) logical use of wind patterns existing during shot tine to _
fall-out, (2) multiple shot (tower or ground) fall-out pattern data froa

Nevada Proving Grounds over last 3 years, and (3) experience snd date froa
IVY-WIkE (limited cross-wind and upwind) and CiSTIS-2rayC itself.

4e Rongerik radiation intensity levels are ‘mown a® caset and evccuaticn

time; calculated roentgen dosage agrees with actual observations froz fi

badges at this site

5. The heaviest fall-cut pattern res expected to pass north of ta: aca
eest cortheast from Ground Zero.

Inelcsure 6

cAI it hielide ne

of H plus 5 and & plus 4 hours, respectively.

Select target paragraph3