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<br />Figure 1.2-11 is an example of the printer plots of lifted cloud top tempera- <br />ture versus precipitation rate. The curve plotted in O's represents the average <br />precipitation rate where the averaging interval is lC. The curve plotted in *'s <br />represents the average precipitation rate where the averaging interval is 3C. At <br />points where the two curves intersect, ='s are plotted. Figure 1.2-12 shows an <br />example of the tabulated data from which figure 1.2-11 was derived. <br />The data for these examples if for the Climax 2NW precipitation station in the <br />Central Colorado Rockies North Massif for the period of record before seeding began <br />at that site. These same data will be used for the rest of this section. <br />The program BMD02D from the UCLA Biomedical Computer Programs (Dixon 1971) was <br />used to produce scatter diagrams such as that shown in Figure 1.2-13. This is a <br />plot of lifted cloud 'top temperature against hourly precipitation rate at the Climax <br />2NW Station. The numbers plotted indicate the number of observations of hourly pre- <br />cipitation in the given category. After the numbers 1-9, the letters A-Z are used <br />to indicate successively higher frequencies. Figure 1.2-14 shows an example of <br />another plot produced by the same program, this one relating an upper air parameter <br />(stability index) to the lifted cloud top temperature. <br />Figure 1.2-15 is a sample of the output from the third analysis program. The <br />average, standard deviation, maximum, minimum, frequency and relative frequencies <br />are calculated for each parameter by 5C intervals of lifted cloud top temperature. <br />1.2.8 Data Analysis. The results of the analysis of master files for each <br />massif were utilized in a systematic manner to arrive at an estimate of potential <br />incremental increase in precipitation. The plots of the various parameters versus <br />lifted cloud top temperature were examined to determine if there were any bias in <br />relation to cloud top temperature. The five degree block average soundings were <br />plotted on Skew T, Log P Diagrams for examination and the data key punched for the <br />area of effect computations. In certain instances there were modifications in the <br />average soundings and these are noted in Section 2 where applicable. If more than <br />one precipitation-CTT curve was available for consideration, the station considered <br />most applicable was selected although frequency of cases also entered into the <br />selection. <br />Once a precipitation-CTT curve was selected for analysis, a critical tempera- <br />ture was de.termined and the area of effect predicted not seeded and seeded curves <br />were adjusted to the station's historical curve as outlined in Section 1.2.1. The <br />remaining work consisted of calculating the percentage increase (at temperatures <br />warmer than the critical temperature and overall), the portion of precipitation in <br /> <br />1-33 <br />