Geoscience Reference
In-Depth Information
Fig. 1.7  Vertical variation of aerosol mean volume radius with height
Substituting for N from Eq. (1.9) in terms of N * and f
3
3
2
rrz
=
a
as
(1.14)
23
/
rrz
=
.
a
as
The mean aerosol size increases with height according to the cube root of z 2
(Eq. 1.14). Vertical variation of aerosol mean volume radius with height is shown in
Fig. 1.7 . As the large eddy grows in the vertical, the aerosol size spectrum extends
towards larger sizes while the total number concentration decreases with height ac-
cording to the f distribution.
The atmospheric aerosol size spectrum is dependent on the eddy energy spectrum
and may be expressed in terms of the recently identified universal characteristics of
fractal fluctuations generic to atmospheric flows (Selvam and Fadnavis 1998 ; Sel-
vam 1990 , 2005 , 2007 , 2009 , 2011 , 2012a , b , 2013 ) as shown in Sect. 1.6.2 below.
1.6.2
Probability Distribution of Fractal Fluctuations
in Atmospheric Flows
The atmospheric eddies hold in suspension atmospheric particulates, namely,
aerosols, cloud drops and raindrops and the size spectrum of these atmospheric
suspended particulates is dependent on the vertical velocity spectrum of the atmo-
spheric eddies. Atmospheric air flow is turbulent, i.e., consists of irregular fluctua-
tions of all space-time scales characterized by a broadband spectrum of eddies. The
Search WWH ::




Custom Search