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<br />. <br /> <br />g/m3. A typical cloud dimension for the clouds studied was in the range <br /> <br />2-4 krn, and less than 10% exceeded 6 krn. <br /> <br />. <br /> <br />An alternate characteristic size of the convective elements within <br /> <br />these clouds was determined by Rodi (1981) from the autocorrelation <br /> <br />lengths in clouds. <br /> <br />Generally, his resul ts indicated that a <br /> <br />. <br /> <br />characteristic scale for the convective elements wi thin clouds was in <br /> <br />the range from 0.2-0.5 krn. Thus, the cumulus clouds that were studied <br /> <br />did not have a simple single-element structure but were rather <br /> <br />. <br /> <br />~om~~ed of multiple regions of varying character. <br /> <br />2.3: <br /> <br />Precipi tation probability. <br /> <br />No systematic study of this <br /> <br />characteristic has been performed, except for the HIPLEX-l clouds. <br />l' <br />However, our general impression is that about half of the clouds <br /> <br />. <br /> <br />stud ied wi th tops colder than -lOoC produced some precipitation at <br /> <br />cloud base, although perhaps only 25 % produced any precipitation <br /> <br />. <br /> <br />reaching the surface. Thus, the CuCg clouds emphasized in this research <br /> <br />were just marginally able to produce precipitation. <br /> <br />2.4: Droplet concentrations. Fig. 2.4 shows a histogram of the <br /> <br />. <br /> <br />frequency with which various droplet concentrations were observed in <br /> <br />the clouds of Montana. Each point represents the maximum I-krn average <br /> <br />observed on one pass through a cloud, and only cloud penetrations <br /> <br />between -5 and -ISoC were included. The range of concentrations was <br /> <br />. <br /> <br />, highly affected by entrainment, and was qui~e variable n9~t only from <br /> <br />day to day but during given cloud p~sses. <br /> <br />Thus these concentrations do <br /> <br />. <br /> <br />not reflect the original CCN content, of the inflow air, but in most <br /> <br />cases have been reduced significantly by entrainment. <br />values were in the range of 400-S00/am3. <br /> <br />Representative <br /> <br />. <br /> <br />8 <br /> <br />. <br />