Ecoinformatics Problems of the World Ocean - New Ecoinformatics Tools in Environmental Science: Applications and Decision-making - page 278

Here the angular brackets <> denote the calculation of the average value for the
annual cycle.
So, the seasonal model of the global carbon cycle developed by Nefedova and
Tarko (1993) and Nefedova (1994) is simulated by a system of 56 ordinary dif-
ferential equations with periodic coef

cients (i =1, … ,14):

C i ¼ H ao

d
dt C i h i

dh i
dt þ V i

H UPL þ L i B i þ B 1d ;

i i

C i ¼ H T þ H TF þ B 2d

d
dt C i H h i

dh i
dt þ V i

ð Þþ ;

i

d
dt C i ð D H Þþ V i C i ¼ L i H TF þ B 3d

;

i

dM i

a

i þ V i H i H i 1

012S i H ao

dt ¼ c

ð Þ 0 : ;

i

i are the anthropogenic carbon emissions in the i-th zone of the atmosphere.

where c

4.5 Modelling the Carbon Cycle in the World Ocean

Along with the physical-chemical processes of transformation of carbon com-
pounds in the hydrosphere mentioned above, the general circulation in the World
Ocean plays an important role in their long-range transport. According to the
available estimates, about 80 % ( 1.7 Gt) of organic matter formed in the process

of photosynthesis descends to deeper layers and oxidizes giving CO 2 . This process
is balanced by a slow lifting of water, and thereby a situation for a stable CO 2
exchange is formed. However, in local situations there are strong deviations from
the stable conditions, which can be described only by the scheme of the spatial-
temporal structure of the ocean waters motion. The block-scheme of this structure
identi

*

es the surface, intermediate, deep, and bottom waters as well as the currents
topography on every horizon. The simulation models of the World Ocean circu-
lation widely vary in the scienti c literature, therefore the development of this part

of the global model unit is not dif

cult.
Following Nitu et al. (2000b), by the depth z the ocean can be divided into four
basic layers: photic to well-heated depths ( ʩ U =U[z i ,z i+1 ], z 0 =0;i =0,1, … ,

m 1); intermediate ( ʩ P =U[z i ,z i+1 ], i = m, ,m+ n 1); deep ( ʩ L =U[z i ,z i+1 ],

- … -

i = m + n, … , m + n + l 1), and bottom ʩ F . By the hydro-physical-ecological

-

characteristics the layer ʩ U as a function of latitude φ , longitude ʻ , and season t can

be attributed to warm or cold waters, the layer ʩ P is photic but always with low

water temperatures, in the layer ʩ L the phytoplankton is not produced. Finally, the

layer ʩ F plays the role of a boundary layer.

On the average, the layer 10 12 m 2 and depth z m ≅ ʩ U has the area 360 × 75 m,

10 12 m 2 . The layer

the warm waters covering area 240 × ʩ P is located at depths