Universal Spectrum for Atmospheric Suspended Particulates: Comparison with Observations: Data Set I - Rain Formation in Warm Clouds: General Systems Theory - page 65

size spectrum. The corresponding standard deviations for the average spectra are
shown as error bars in Figs. 3.2a . The average values of mean volume radius, total
number concentration, the number of spectra and the upper and lower bounds of
particle size (radius) intervals are given in Fig. 3.2b .
The portion of the total average aerosol size spectrum corresponding to the ac-
cumulation mode (up to 1 µm or normalized diameter equal to 4) shows a reason-
ably good fit (within plus or minus two standard deviations) to the model predicted
universal spectrum. The source of the uncertainties displayed by the error bars may
be due to measurement noise, independent in every size interval, also may be due
to different aerosol sources. The coarse mode (diameter > 1 µm) portion of the total
average aerosol size spectrum shows significant departure from the model predicted
spectrum and may be attributed to a different source region for the suspended par-
ticulates with a different density. The model predicts universal spectrum for sus-
pended aerosol mass size distribution (Sect. 1.6.4), based on the concept that the
atmospheric eddies hold in suspension the aerosols and thus the mass size spectrum
of the atmospheric aerosols is dependent on the vertical velocity fluctuation spec-
trum of the atmospheric eddies.

3.6.3 Analysis Results, Data III: CARG Aerosol and Cloud Data

from the Convair-580, Cloud Drop Size Spectra

Cloud drop size/number concentration from Project SAFARI 2000, CARG Aerosol
and Cloud Data from the Convair-580. A total of 7 data sets are available for the
study. Cloud drop size spectrawere computed for data sets for which the cloud liq-
uid water content (Johnson-Williams) was more than zero.
The cloud drop size/number concentrations ranging in diameter from 1.70 to
47.0 µm were measured in 15 channels (size ranges). The arithmetic mean radius
of the class interval was used for computing d(ln r an ). The data sets were obtained
from ftp://ftp.daac.ornl.gov/data/safari2k/atmospheric/CV-580/data/. The average
aerosol size spectra for each of the 7 data sets are plotted on the left-hand side
and the total average spectrum for the 7 data sets is plotted on the right and side
in Fig. 3.3a along with the model predicted scale independent aerosol size spec-
trum. The corresponding standard deviations for the average spectra are shown as
error bars in Figs. 3.3a . The average values of mean volume radius, total number
concentration, the number of spectra, the number of class intervals for each of the
7 data sets, and the upper and lower bounds of particle size (radius) intervals are
given in Fig. 3.3b .
The individual and total average cloud droplet spectra show a close fit to model
predicted universal spectrum for cloud drop diameter more than 5 µm (correspond-
ing to normalized diameter equal to 1). The observed spectra show appreciably larg-
er radii than model predicted for normalized radius size range less than 1 and may
be attributed to the large increase in the sampled median volume diameter, from
about 5 to 20 µm during flights 5 to 7 (Fig. 3.3b ). However, even in this region for