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<br />NOVEMBER 1983
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<br />HEGGLI ET AL,
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<br />FIG. 6. (a) LWC distribution shown as a percentage of in cloud
<br />observations by 2.50C temperatu~e intervals for banded echo types;
<br />(b) same as (a) except ICC shown; (c) same as (a) except LWC/ICC
<br />shown. I
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<br />t" mountaln bamers have 1 been shown by Hobbs
<br />t (1975a,b), Marwitz (1980)) and Lamb et al. (1976).
<br />" Figures 8-10 show the effect of the Sierra Nevada
<br />barrier on the cloud micro~hysics. The scribed bound-
<br />aries delineate an area within which there were 100
<br />or more in-cloud observations drawn from 10 km by
<br />50C grids. The Sierra mourttain barrier projection, atso
<br />shown in the following figures, was constructed by
<br />conversion of terrain elevations, averaged from 40 km
<br />north through 40 km south of a true east-west line
<br />from the SKYWATER radar, to temperatures taken
<br />from the standard atmosphbretemperature-to-altitude
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<br />relatioMmp. .s~~ re~~[~~~~ 1= iliM
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<br />those of the standard atmosphere, the data were usually
<br />closer to the crest projection than shown.
<br />Examined here are the relative frequency of time
<br />the following microphysical conditions existed: 1) LWC
<br />exceeded 0.1 g m-3, 2) ICC were less than 5 L-1, and
<br />3) LWC/ICC ratio exceeded 10 J-Lg per crystal. These
<br />minimum conditions are believed to be necessary for
<br />seeding potential based on in cloud seeding experi-
<br />ments made in the Sierra and reported by Marwitz
<br />and Stewart (1980).
<br />Figures 8a-c show the cloud microphysics cross sec-
<br />tions for the area-wide echo types. Fig. 8a depicts a
<br />general absence of LWC greater than 0.1 g m-3, but
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<br />FIG. 7. (a) L WC distribution shown as a percentage of in cloud
<br />observations by 2.50C temperature intervals for cellular echo types;
<br />(b) same as (a) except ICC shown; (c) same as (a) except LWC/ICC
<br />shown.
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