Because the cloud did not cool at the same rate uniformally throughout
its volume, a vertical distribution of cloud material was observed at
stabilization.
In the simple case of an ideal, strongly streamline
toroidal circulation of the outer portions of the cloud cooled more rapidly
and stabilized at lower altitudes than the inner portions,
Considerations
of the surface relative to the volume of a cloud indicated that the
altitudes of the top and base should be observed to be a power function of
the yield of the explosion in a uniform atmosphere,
Scientists frequently
observed the temperature profile of the atmosphere above the tropopause,
however, to be isothermal or sometimes to show a positive lapse rate, such
as inversion,
Clouds from higher yield explosions, therefore, had their rise
strongly dampened by this temperature structure when they rapidly attained
temperature equilibriumwith the atmosphere above tropopause altitudes,
The
altitude of the primary mass of cloud material was related to yield.
Scientific personnel made observations at the Nevada Proving Grounds of many
explosions both at moderately high altitudes and relatively close to the
ground, the range of burst height in most cases lying between ,000-5,000
feet mean sea level.
No attempt was made to correct for difference in height
of burst for these data since particular atmospheric conditions such as
temperature inversions, degree of wind shear, and humidity appeared to
affect stabilization altitudes more than moderate differences in turst
height.
Because of these factors as well as the effect of the stratospheric
20h
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