Geoscience Reference
In-Depth Information
2
3X
3
2
z
eq
z
b
z
eq
z
b
1
2
9
;
0
2
Usz
b
¼
þ
ð
5
:
21
Þ
b
where z
eq
is the stable height of the jet over the stack, z
b
is the height of the bottomof the
stable atmospheric layer over the stack, U is thewind speed at the height of the stack,
ʲ′
is
the effective coef
0.4), s is the parameter of stability, X is
the jet buoyancy parameter. The s parameter depends on the potential temperature
gradient
cient of aerosol capture (
ʲ′ ≅
cient). The
F parameter can be calculated as the function of velocity v of the jet emitted from the
stack, internal radius R of the stack, and temperature T of the emitted jet:
ʸ
and air temperature T
a
:
s ¼ g
ð
=
T
a
Þ@h=@
z (g is the gravity coef
F ¼ g
m
R
2
T
T
a
ð
Þ=
T
nd z
eq
, and the effective
height Y of the jet is found as the sum: Y ¼ z
eq
þ
h
s
, where h
s
is the height of the
stack. The whole zone of the aerosol cloud propagation with wind s blowing from
the water towards land is divided into zones of stability, instability, and the aerosol
cloud lowering. Such a digitization of space simpli
With the z
d
value known from (
5.21
) one can easily
es the model, reducing the
needed data base and increases its reliability. In each zone, the use of the Gauss-
type model leads to a simpli
ed parameterization of the process of aerosol scat-
tering and facilitates an interpretation of the modeling results.
In the undisturbed dispersion zone, the distribution of the aerosol jet in the
homogeneous stable atmospheric layer is described with the base Gaussian equation
of scattering:
"
#
2
Q
1
2
k
r
k
C
ð
u; k;
z
Þ
¼
r
k
r
z
exp
p
2
U
(
"
#
"
#
)
2
2
1
2
z
Y
r
z
1
2
z
þ
Y
r
z
exp
þ
exp
where U is the wind speed, Y is the effective height of the jet,
˃
ʻ
and
˃
z
are
parameters of the horizontal and vertical dispersion.
In the zone of fumigation, the forces get activated which cause a distortion of the
jet due to instability of heat
fl
fluxes in the surface layer. In this zone the following
approximation is valid:
"
#
Z
u
2
Þ
Q
1
1
2
ð
p
0
2
k
r
0
C
ð
u; k;
z
Þ
¼
Þ
U
exp
þ
3
=
2
r
0
r
z
u
ð
; u; u0
ðÞ
2
0
(
"
#
"
#
)
dp
0
d
2
2
ð
z
Y
Þ
ð
z
þ
Y
Þ
u
0
d
u
0
;
exp
þ
exp
2
r
z
ð
u
; u; u
0
Þ
2
r
z
ð
u
; u; u
0
Þ
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