Geoscience Reference
In-Depth Information
from z
m
to z
m+n
≅
200 m. In concrete model realizations given in Krapivin and
Kondratyev (2002) the following assumptions have been made: m = 10, n =2,l =8.
The vertical CO
2
transport in the ocean is determined by advective
uxes H
19
;
ij
and
fl
ux H
20
;
ij
). An advective
transport from the i-th into the j-th reservoir of the ocean is considered proportional to
the concentration of carbon in the respective reservoirs: H
19
;
ij
=
gravitational sedimentation of dead organic matter (the
fl
ʻ
2,ij
C
a,i
(a = U,P,L),
where
ʻ
2,ij
= V
ij
/V
i
,V
ij
is the water volume transported per unit time from the i-th
reservoir into the j-th reservoir; Vi
i
is the volume of the i-th reservoir.
The following algorithm is widely used for the parameterization of the process of
carbon sedimentation. The
flux under unit area of the ocean is supposed to decrease
exponentially with depth. If we denote the in
fl
fl
ow of organic matter in the i-th reservoir
as g
i
and the net out
fl
ow of organic matter from the water surface as H20T,
20T
,weobtain:
H
20
;
1
¼ H
20
;
T
;
H
20
;
i
¼ g
i
1
r
i
=r
i
1
ð
Þ
exp
z
i
z
i
1
½
ð
Þ=
D
s
;
ð
i ¼ 2
; ...;
m
þ
n
þ
l
Þ;
where
˃
i
is the area of the i-th reservoir, D
s
is the characteristic time of the organic
matter particles sedimentation before their decomposition. The rate of decompo-
sition in each reservoir is equal to:
R
D
;
i
¼ H
20
;
i
H
20
;
i
þ
1
;
Þ;
R
D
;
F
¼ H
20
;
m
þ
n
þ
l
H
16
:
ð
i ¼ 1
; ...;
m
þ
n
þ
l
However, if the time of the transition of the organic matter particles from one layer
to another is short compared to D
s,
then it is better to take H
20
;
i
¼
k
1
C
a
;
i
;
H
16
;
i
¼
k
4
C
F
;
i
:
fluxes of detritus
decomposition, solution of bottom sediments, and carbon consumption in the process
of photosynthesis:
In addition to these
fl
fluxes, one should take into account the
fl
H
17
;
i
¼ Const
H
18
;
i
¼
k
3
D
L
;
i
;
H
22
;
i
¼
k
3
D
U
;
i
;
H
21
;
i
¼ C
31
R
U;
i
:
:;
The estimates for the modeled parameters of the particular oceanic processes of
carbon cycle scatter widely. For instance, from the data of various authors the
estimates of assimilation of carbon from the hydrosphere in the process of photo-
synthesis range from 10 to 155 Gt C/year. The value 127.8 Gt C/year is the most
widely used. However, because of large dispersions of these estimates the calcu-
lation of the C
31
coef
cient is fraught with a great uncertainty and therefore
numerical experiments with the use of other, more accurate data are required in
order to be speci
ed.
Finally, let us suppose the surface layers of the ocean are
filled with carbon due to
its run-off from the land H
24
;
i
¼ C
7
W
sio
;
H
23
;
i
¼ C
8
W
Hio
;
where W
sio
and W
Hio
are the
river and underground run-offs into the World Ocean, respectively.
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