PREDICTION OF SUBSURFACE-DETONATION FALLOUT
{
347
0.0001
NORTH
0.0100
r= 0. 1000
> 10 NAUTICAL:
MILES
ere eee eee eee ee ee ee te
Rw ge ee ee ee ee
Fig. 8—-The machine-plotted (H+ 1)-hr gamma-dose-rate pattern for
the Danny Boy shot (diagnostic calculation), roentgens per hour.
shot. The observed winds at shot time, the observed cloud geometry,
the published fission yield of 1.2 kt, and a value of 0.85 (an early preliminary value) for F. were input tothe model. Figure 10 shows thecalculated and the observed (H + 1)-hr gamma dose rate as a function of
distance along the hot line of the pattern. A comparison of these two
dose rate vs. distance curves shows that the largest error between
calculation and observation is of the order of a factor of 2.5. An examination of the radiosonde observation near shot time at the Nevada Test
Site indicates that the vertical temperature distribution of the layer
through which the particles were falling was slightly superadiabatic.
Under such conditions, it is possible that the vertical eddy diffusion on
the day of the Teapot ESS shot was larger than average. If enhanced
vertical eddy diffusion were operative, the dose rate would have been
slightly less near ground zero and would have been enhanced downwind.
Other model confirmation tests have been performed, These include
calculations with the surface-burst version of the model on the Apple I
and the Zucchini shots? and on several other atmospheric shots for
which the data are still classified. The results of these additional tests
were Satisfactory.