Geoscience Reference
In-Depth Information
On average during the fall and winter the currents are directed along the coast line
in a north-easterly direction (
=45
o
). During the remaining time the currents have
ʱ
= 225
o
). The speed value is varied insigni
the opposite direction (
ʱ
cantly both in
6kmh
−
1
. The further
space and in time. Near the coastline this speed equals to 2
-
4.8 km h
−
1
. It is supposed that
one gets from coastline the speed variations are 0.7
-
depths the h
ij
are constant on the whole aquatory
. The vertical gradient of the
water temperature is considered as negligibly small. The synoptic regime during the
year is approximated by a binary situation: the rainy season exists during May
ʩ
-
October, while from November to April the dry season takes its place.
Table
4.13
consists of some results of oil pollution measurements by means of
Adaptive Identi
er. Simulation results are given in Figs.
4.29
and
4.30
. As follows
from Fig.
4.29
under the above suppositions, the average annual distributions of oil
hydrocarbons on the aquatory
ʩ
are essentially nonuniform. Taking an average by
the seasons eliminated the in
uence of pollution drift by the currents and revealed
the places where oil hydrocarbons always come to the upper sea layer. The degree
of oil hydrocarbon accumulation in the surface-water layer varies between the limits
of 25
fl
130 mg m
−
2
. This is sometimes higher than the oil hydrocarbon concen-
tration in the open ocean and signi
-
cantly lower than in the very polluted waters.
Figure
4.30
forecasts the oil hydrocarbon distribution on the whole aquatory
ʩ
.
ʩ
B
is a
constant equal to 0.001 mg L
−
1
and is brought into
ʩ
in conformity with the
scheme of the currents stored in the ESECEZ database.
It was supposed that the oil hydrocarbon concentration (O) on the boundary
Table 4.13 Results of measurement data processing during the
field study of oil products content
in the water (mg L
-1
) on the South Vietnam territory
Depth (m)
Sai Gon River
Dong Nai River
Day hours
Day hours
9
15
18
9
15
18
0.1
0.052
0.101
0.047
0.019
0.019
0.011
0.5
0.061
0.094
0.06
0.012
0.013
0.015
1.0
0.063
0.085
0.053
0.012
0.012
0.013
1.5
0.066
0.103
0.061
0.010
0.010
0.011
2.0
0.054
0.077
0.088
0.009
0.010
0.007
2.5
0.051
0.049
0.064
0.008
0.007
0.006
3.0
0.062
0.068
0.048
0.006
0.008
0.005
4.0
0.043
0.094
0.034
0.004
0.009
0.004
5.0
0.048
0.083
0.026
0.001
0.002
0.006
6.0
0.059
0.074
0.055
0
0
0
7.0
0.062
0.052
0.084
0
0
0
8.0
0.041
0.043
0.054
0
0
0
9.0
0.042
0.049
0.077
0
0
0
10.0
0.037
0.055
0.038
0
0
0
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