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(USA)
371. PUB. DATE (YYMMDD)
34.
CLASSIF.
950. ABSTRACT
600601
LEVEL TEXT
t
Unclassified
.
(This document was previously published as
DASA-532, a Special Report to the Government of
Argentina.) The’ HASP program has operated since the fall
of 1957. The sampling network using U-2 aircraft has
collected 10{sup 8} standard cubic feet of air from
57{sup 0}S to 7l{sup O}N up to 70,000 ft. Ashcan data is
used for upward extrapolation. IPC Paper 178 of near
100% efficiency is used. Stratospheric matter sampled is
in the
0.01
{mu}
range.
The uneven distribution of
material in the stratosphere has been noted.
Stratospheric inventories of
{sup
90}Sr have been
calculated for the periods Nov 1957 to Dec 1958, Jan to
Aug 1959, and Sep to Nov 1959 to be, respectively, 0.95,
0.81, and 0.7 MCi. Concentrations have been greater in
the Northern Hemisphere by a factor of 2 or 3 over the
southern Hemisphere.
The
{sup
90}Sr maximum occurs
in
the equatorial regions around 90,000 ft and slopes down
to a round 70, 000 ft in the polar regions. Little
fractionation is noted in stratospheric debris.
{sup
coefficients
cm{sup
137}Cs to {sup 90}Sr ratios are 1.8 to 0.5. A
semi-empirical application of Gaussian diffusion is
described which suggests that hot clouds injected in the
equatorial stratosphere spread in the North-South
direction with mixing coefficients near 5 x 10{sup 8}
em{sup 2}/sec. Vertical mixing is slower with
801.
KEYWORD(S)
of 4 x 10{sup 3}
and 2 x 10{sup 4}
2}/sec suggested for tropical and polar regions,
respectively. An Injection-Depletion model is offered
which indicates that as much as 50% of the material
produced in a megaton ground surface burst bcomes down
in local fallout. Removal from the stratosphere occurs
at different rates depending on altitude and latitude of
injection and season of the year. Effective
half-residence times of, respectively, 5, 10, and 20
months for polar, low equatorial and high equatorial
debris is suggested. Surface concentrations of {sup
90}Sr are displayed as a function of latitude and time.
The Northern hemisphere carries 3/4 of the burden.
FALLOUT/sampling ;HARDTACK/;HASP/;
STRATOSPHERE/radioactivity ;RUSSIAN ATOMIC.
EXPLOSIONS/fallout ;RESIDUAL RADIATION/meastirement ;
AIRCRAFT; CESIUM 137;DOSE RATES;FALLOUT;FISSION PRODUCTS;
HARDTACK; HASP; STRONTIUM 90;AERIAL MONITORING; RADIATION
HAZARDS ; RADIOACTIVITY ; MEASUREMENT
Item 70
I0034 13
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