Geoscience Reference
In-Depth Information
whereas the deep ocean remains motionless, the pressure forces there
are null.
Figure 2.9.
Theoretical configuration of the two-layers of ocean
This two-layer model (Figure 2.9) enables us to calculate the
expression of the pressure forces in the deep layer and if we apply
the hypothesis that the gradient of pressure forces cancels itself out
there by equaling the pressure between PA and PB, we find:
PA =
ρ
1
g
(
δ
s
+
h
1
+
δ
h
) +
ρ
2
g h
2
= PB =
ρ
1
g h
1
+
ρ
2
g
(
h
2
+
δ
h
)
where
ρ
1
is the volumic mass of the surface layer,
ρ
2
that of the deep
layer,
δ
s
is the surface elevation of the ocean and
δ
h
the elevation of
the thermocline.
Thus:
ρ
1
(
δ
s
+
δ
h
) + =
ρ
2
δ
h
From whence
δ
h
is expressed:
δ
h
= -
ρ
1/
(
ρ
ρ
2
)
δ
s
1 -
This expression shows that the surface slope and the thermocline
slope are in opposition and in a ratio
ρ
1/
(
ρ
ρ
2
), which is in general
1 -
