Geoscience Reference
In-Depth Information
081106a_10.txt, 081108a_10.txt, 081110a_10.txt, 081112a_10.txt, 081113a_10.txt.
The letter is 'a' for first flight. Maximum data frequency is 10 s
−1
indicated as '_10'
in the file name.
4.3
Analysis and Discussion of Results
The atmospheric suspended particulate size spectrum is closely related to the verti-
cal velocity spectrum (Sect. 1.6). The mean volume radius of suspended aerosol
particulates increases with height (or reference level
z
) in association with decrease
in number concentration. At any height (or reference level)
z
, the fractal fluctua-
tions (of wind, temperature, etc.) carry the signatures of eddy fluctuations of all
size scales since the eddy of length scale
z
encloses smaller scale eddies and at the
same time forms part of internal circulations of eddies larger than length scale
z
(Sect. 1.4). The observed atmospheric suspended particulate size spectrum also ex-
hibits a decrease in number concentration with increase in particulate radius. At any
reference level
z
of measurement the mean volume radius
r
as
will serve to calculate
the normalized radius
r
an
for the different radius class intervals as explained below.
The general systems theory for fractal space-time fluctuations in dynamical sys-
tems predicts universal mass size spectrum for atmospheric suspended particulates
(Sect. 1.6.4). For homogeneous atmospheric suspended particulates, i.e., with the
same particulate substance density, the atmospheric suspended particulate mass and
radius size spectrum is the same and is given as (Sect. 1.6.4) the normalized aerosol
number concentration equal to
1
N
d
N
lnr
versus the normalized aerosol radius
r
an
,
d
(
)
an
r
r
where (i)
r
an
is equal to
,
r
a
being the mean class interval radius and
r
as
the mean
a
as
volume radius for the total aerosol size spectrum, (ii)
N
is the total aerosol number
concentration and d
N
is the aerosol number concentration in the aerosol radius class
interval d
r
a
, and (iii) d(ln
r
an
) is equal to
dr
r
a
for the aerosol radius class interval
r
a
a
to
r
a
+ d
r
a
.
4.3.1
Analysis Results, VOCALS PCASP-B Aerosol
Size Spectrum
A total of 17 data sets between 14 October and 13 November 2008 are available for
the study. The data used in this study for each of the 17 flights are (i) average and
standard deviation for particle number concentration per cc in 29 class intervals
ranging from.1 to 3 µm for the particle diameter, (ii) average and standard devia-
tion for total particle number concentration per cc (bins 2-30), and (iii) average and
standard deviation for total volume (cc).
Details of data sets used for the study are shown in Figs.
4.1
(
a
-
d
) as follows. (i)
Fig.
4.1a
: lower and upper radius size limits for bin numbers 2-30, (ii) Fig.
4.1b
:
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