Universal Spectrum for Atmospheric Suspended Particulates: Comparison with Observations: Data Set II - Rain Formation in Warm Clouds: General Systems Theory - page 74

Fig. 4.1 a Lower and upper radius size limits for bin numbers 2-30. b Average and standard
deviation for total particle number concentration per cc for the 17 flights. c Average and standard
deviation for total volume (cc) for the 17 flights (bins 2-30). d Average and standard deviation for
mean volume radius (µm) for the 17 flights
for the 17 flights (bins 2-30), and (iv) Fig. 4.1d : average and standard deviation
for mean volume radius (µm) for the 17 flights. The dispersion (equal to standard
deviation/mean) expressed as percentage gives a statistical measure of variability of
measured particle number concentration. Computed dispersion (%) values are plot-
ted for the two size ranges (i) less than 1 µm diameter (bins 2-20) and (ii) 1-3 µm
diameter (bins 21-30) in Fig. 4.2a, b respectively.
The average total number concentration exhibits a variability of about ± 100 cc −1
around a mean value of about 200 cc −1 except for the first three flights which show
larger variability (Fig. 4.1b ). The total volume is one order of magnitude larger for
flight numbers 10 onwards compared to earlier flights (Fig. 4.1c ) consistent with
larger median volume radii for flight numbers 10 onwards (Fig. 4.1d ) and exhibit
large variability, particularly for size ranges more than 1 µm (Fig. 4.1d ).
For particle diameter range less than 1 µm (bins 2-20) the computed dispersion
(%) for particle number concentration is within 100% for bins 2-14 size range
and thereafter increases rapidly to a maximum of 500 %. The computed dispersion
(%) for particle number concentration for bins 21-30 (1-3 µm diameter) increases
steeply from 500 %-5000 % with increase in particle size.
The mid-point diameter of the class interval was used to compute the corre-
sponding value of d(ln r an ). The average aerosol size spectra for each of the 17 data