Geoscience Reference
In-Depth Information
The calculating procedure is based on the subdivision of the Arctic Basin into
boxes {
ʞ
ijk
}. This is realized by means of a quasi-linearization method (Nitu et al.
2000a). All differential equations of the SSMAE are substituted for in each box
ʞ
ijk
by easily integrable ordinary differential equations with constant coef
cients. The
water motion and turbulent mixing are realized in conformity with current velocity
fields which are de
ned on the same coordinate grid as the {
ʞ
ijk
} (Krapivin et al.
1998a).
6.4.3 Description of Ecological Processes
The ice-water ergocline plays an important role in the biological productivity of the
north seas. According to the hypothesis of Legendre and Legendre (1998), energetic
ergoclines are the preferential sites for biological production in the Arctic Ocean.
The primary production in the food chains of the Arctic Basin ecosystems is
determined by the phytoplankton productivity. This is connected with complex
variations in the meteorological, hydrodynamic, geochemical and energetic
parameters of the sea environment. The problem of parameterization of the phy-
toplankton production in the north seas was studied by Legendre and Legendre
(1998). Table
6.6
gives the structure for the seasonal composition of conditions
affecting the primary production in
ʞ
ijk
.
The block MWT calculates the water temperature T
w
by means of the averaging
of temperatures for the mixed water volumes. In addition the following correlations
are applied:
Ω
. This scheme is applied for each of the
(
0
:
024b
þ
0
:
76T
0
þ
8
:
38 when
b
50 cm
ð
6
:
1
Þ
T
g
¼ T
r
¼ T
f
¼
0
:
042 b
þ
0
:
391T
0
0
:
549 when
b
50 cm
\
where b=g+ r + f, T
0
is the surface temperature, g is the snow depth, r is the
thickness of the
floating ice and f is the depth of the submerged ice below the water
surface. If we designate by
fl
the density of snow, ice and seawater
respectively, we obtain for the depth of ice beneath the surface:
ˁ
g
,
ˁ
r
and
ʶ
Table 6.6 The vertical
structure of the Arctic Basin
'
s
water bodies
Layer (A)
ʔ
z
Parameters of the layer
T
A
ʱ
A
ʲ
A
E
A
k
A
Surface
0
T
0
E
0
Snow
g
T
g
E
g
ʱ
g
ʲ
g
Floating ice
r
T
r
E
r
ʱ
ʲ
r
r
Drowned ice
f
T
f
E
f
ʱ
ʲ
f
f
ʱ
W
ʲ
W
Water
z
−
f
W
E
W
k
W
D
z layer thickness, T
A
temperature, E
A
illumination, k
A
turbulence
coeffi-
cient,
ʱ
A
coeffi-
cient of illumination attenuation,
ʲ
A
coeffi-
-
cient of light reflection
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