098
400
450
300
PRESSURE, MB
ge
ye
350
650
700
750
DEW POINT
AT 0409 PST
800 -—
er
900 bk
DEW POINT
B
TEMPERATURE \
0409 PST
WN
0905 sor
"pau
AT 0905 PST™7]
‘,
1000 -—
wsoL_l i
-~40
-30
\
| Ji} |
~20
3
5
JI\) Vi!
~10
0
TEMPERATURE, °C
W~*
10
\7
N VY | ft
10
20
30
Fig. 7—Vertical distribution of temperature and humidity at 0409 PST
at San Nicolas and at 0905 PST at Point Arguello on Feb. 7, 1962.
The concentration of debris in rain formed by the coalescent growth of
tiny droplets should be greater than that in rain formed by diffusional
growth of ice crystals since many more nucleation particles per drop
of rain are involved in the former process. However, coalescent growth
occurs mostly in the lower levels of the atmosphere where there are
greater amounts of condensation nuclei from terrestrial origin, Since
*Sr-bearing particles are of stratospheric origin, the expected increase in all water-growth raindrops may not be very large. In five
storms that occurred during our studies of large-scale uplift in central
Pennsylvania, the precipitation growth changed from an ice—water
mechanism to an all-water mechanism. Such changes occurred in
periods of precipitation from single air masses, with other cloud
parameters such as tops and ceilings relatively constant. The data are
shown in Table 2. The “Sr concentration changed by a factor of about
3.5 in going from an ice to an all-water mechanism, The factor was
about the same for the periods of pre- and post-U.S.S.R. testing in the
fall of 1961.