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<br />The relatively cold cloud bases of Montana lead to maximum liquid' <br /> <br />water contents that, for adiabatic ascent, are only 3-4 g/m3. <br /> <br />Reductions to less than 50% of the adiabatic values are cannon in <br /> <br />cumulus clouds (Warner, 1955; Rodi, 1981), so only about 2 g/m3 maximum <br /> <br />liquid water contents are likely in these clouds. As we will argue later <br /> <br />in this report, this imposes an important limitation on the potential <br /> <br />for accretional growth of precipi tation, and leads to inefficiencies <br /> <br />in both natural and seeded precipitation development. <br /> <br />2.2: Clooo horizontal dimensions. Cloud passes in 1978 flown at <br /> <br />temperatures between -6 and -120C were examined to determine the <br /> <br />representative sizes of the clouds. The result is shown in Fig. 2.3. The <br /> <br />size of the cloud was determined from the horizontal distance over <br /> <br />which the liquid water content (measured by the FSSP) exceeded 0.01 <br /> <br />10 <br /> <br /> <br />100 <br /> <br />- 8 80 <br />E ~ <br />~ 0 <br />C\I <br />0 6 60 w <br />- > <br />"- ~ <br />a:: <br />w <I <br />m 4 40 ...J <br />~ ::J <br />:::> :E <br />z ::J <br /> (J <br /> 2 20 <br /> 0 0 <br /> 0 2 4 6 8 10 <br /> LENGTH OF PASS (km) <br /> <br />Fig. 2.3: Differential (thin line) and cumulative (thick line) <br />distributions of the cloud width, defin~ as the distance over which <br />the liquid water content exceeded 0.01 g/m. Cloud penetrations between <br />the -6 and -12oC levels in 1978 were used to construct this plot. The <br />indicated maximum at 6 km was the initially-proposed maximum size <br />permitted for a HIPLEX-1 candidate; this was later increased to 8 km <br />before the start of the experiment. <br /> <br />7 <br /> <br />