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About figure 7a: During SPECTRA 1, the supersaturation settings that were operative inside the CCN <br />instrument during the research mission were usually set to cycle through a supersaturation of 0.1% for 3 <br />minutes, 0.25% for 2 minutes, 0.5% for 2 minutes and 1% for 2 minutes. In this case, the cycle time of <br />one supersaturation cycle is approximately 9 minutes. When the CCN data is processed, the exact <br />-3 <br />supersaturation is calculated and the plot of CCN number concentration (cm) across calculated <br />supersaturation (SS) is generated. The CCN instrument changes the supersaturation by adjusting the <br />temperature difference between the temperature controllers at the top of the column, the middle and the <br />base of the column. The instrument works best when the temperature in the column is stable (not <br />changing), so the data in between the supersaturation settings cannot be viewed as being an absolute <br />CCN concentration that corresponds to that exact supersaturation value. This leads to some variation in <br />the data when the CCN concentration is plotted as a function of supersaturation. <br />About figure 7b: The CDP Effective Diameter plots are for cloud droplet concentrations greater than 100 <br />-3 <br />cm. This threshold value ensures that the aircraft was penetrating the convective cloud volume and not <br />a cloud fragment. <br />About figure 7c: The CIP Effective Diameter data plotted is also for cloud droplet concentrations greater <br />-3 <br />than 100 cm. The reason for this threshold is to remove the data points that appear to be concentrations <br />of rainfall particles that have precipitated from the cloud bases. These data are usually removed prior to <br />-3 <br />applying the 100 cmthreshold because the ordinate is the cloud depth, and the cloud base should be <br />close to the 0 meter value. <br />-3 <br />About figure 7d: The threshold for the CDP number concentration is reduced to 50 cm.The threshold is <br />reduced in this plot because maritime clouds with low CDP concentrations could still display CIP number <br />concentrations. In section 4.4 of this report, the plots in figure 7c and 7d are merged. The resultant plot <br />th <br />for the same data set on the 19 August 2004, is shown in figure 7e below. <br />Figure 7e: This plot shows the data from figure 7c and 7d merged <br />into one plot. Such data is presented in section 4.4 of this report. <br />29 <br />