Geoscience Reference
In-Depth Information
6.5.4 Experiments Using the Angara-Yenisey River System
Simulation Model
The AYRSSM database includes estimates of the model coef
cients, initial infor-
mation for the climatic and anthropogenic scenarios and a set of identi
ers {A
i
}
describing the
area by its boundaries, thus giving the structure of the land-water
surface. The CON block provides an interface with the database and allows the user
to modify its elements.
It is assumed that the vertical distribution of pollutants in the river water is
homogeneous, the pollution of the soil and plants is negligible and the cleaning
process of the atmosphere has an exponential character with half-life
Ω
˄
a
(
˄
a
= 10 days
when t
2
½t
1
;
t
2
,
˄
a
= 20 days when t
2
½t
2
;
t
4
). It is believed that the pollution sources
located on the
territory support a constant level of distribution of the pollutants. The
distribution function is uniform on the intervals shown in Table
6.17
. The values of
Ω
ʾ
,
ʼ
and v were determined by average estimates for the last 3 years on the base of
published data (Rovinsky et al. 1995) and data of the Irkutsk Scienti
c Center of
Russian Academy of Sciences. The AYRS slope is taken equal to 0.21 m/km. Eco-
logical elements of the AYRS are considered as having unique levels with biomass
ʲ
t
i
þ
½
(i = 1, 2, 3). The equation for H
5
m
is written in the form: H
5
m
¼½g
1
þ
m
1
m
2
b
Q
k
m
D
(t), a constant value at each of the intervals t
i
;
where g
1
is the gravitation coef-
ficient (0.05 day
−
1
), m
1
is the mortality coef
ficient (0.01 day
−
1
) and m
2
is the pollutant
cient (0.03 kg
−
1
).
Table
6.17
gives an example of using the AYRSSM for the estimation of
137
Cs
distribution in the
capture coef
Ω
area where the cells
X
i
are situated along the AYRS with the
x = 10 km. The
137
Cs distribution along the river system
has a single maximum which changes in value and coordinate over time. A similar
picture is observed for other radionuclides from Table
6.16
. Such a result is not
step of discretization at
ʔ
137
Table 6.17 Relative concentrations of
Cs in water (
ʳ
w
) and in bottom sediments (
ʳ
d
)
normalized for values at x =0
Distance from Lake Baikal
(km)
Time from the beginning of the simulation experiment (days)
30
60
90
120
x
c
w
c
d
c
w
c
d
c
w
c
d
c
w
c
d
0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
250
8.2
20.4
6.7
18.7
7.4
17.8
8.3
17.1
500
9.5
14.4
9.4
12.3
9.3
15.3
8.4
14.9
1,000
10.3
4.1
8.8
9.8
7.8
11.6
7.9
10.3
1,500
9.7
3.0
10.2
5.2
6.3
8.5
4.8
7.6
2,000
8.9
2.9
6.9
2.9
4.9
4.1
4.5
2.8
2,500
6.5
2.3
5.9
2.2
3.1
2.4
3.1
1.8
3,000
3.2
1.9
2.7
1.7
2.9
1.9
3.0
1.4
3,500
2.5
1.6
1.8
1.1
1.8
1.2
2.4
1.1
4,000
1.7
1.1
1.6
0.9
1.8
1.2
1.4
1.1
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