6
1 Introducing Sea Water
r::-- 1030
8
-- eo 1025
C
.g
CJl
1020
~
Qj
"0
....
~ 1015
~
1010
1005
1000
995
990
0
5
10
15
20
25
30
35
40
Temperature (C 0)
Fig. 1.2: The density of fresh and sea water as a function of temperature and salinity
to about 917 kg/m 3 . When sea water freezes, its salt is extruded and sea ice
floats like freshwater ice at the surface.
A difference of 1 ppm in salinity has an effect on the density of sea water
which is about five times greater than the change caused by a difference of
1°C in temperature. Large scale density structure of the ocean is dominated
by variations in temperature while salinity differences have very appreciable
effects on smaller scale motions. The densest waters are formed under the ice
of the Weddell Sea in the Antarctic, in the North Atlantic off Greenland and
in the Norwegian Sea.
The general dependence of the sea water density Pw(S, T, p) on the salinity,
S, temperature, T, and pressure, p, is called the equation of state for sea
water. There have been many attempts to establish the relationship Pw(S, T, p)
in the past (for more details see Dera, 1992) and the modern algorithm of
determination of density for given salinity, S, temperature, T, and pressure, p,
was developed by the international group of experts on standards (UNESCO,
1987). The expression for Pw(S, T,p) is rather complicated and it will not be
given here.
For convenience, in Appendix D a computer program, DIl, for calculating
density of water for arbitrary values of temperature, T, and salinity, S, is given.
Here, only some values of Pw (S, T, p), frequently used in the book, are given:
1 Introducing Sea Water
r::-- 1030
8
-- eo 1025
C
.g
CJl
1020
~
Qj
"0
....
~ 1015
~
1010
1005
1000
995
990
0
5
10
15
20
25
30
35
40
Temperature (C 0)
Fig. 1.2: The density of fresh and sea water as a function of temperature and salinity
to about 917 kg/m 3 . When sea water freezes, its salt is extruded and sea ice
floats like freshwater ice at the surface.
A difference of 1 ppm in salinity has an effect on the density of sea water
which is about five times greater than the change caused by a difference of
1°C in temperature. Large scale density structure of the ocean is dominated
by variations in temperature while salinity differences have very appreciable
effects on smaller scale motions. The densest waters are formed under the ice
of the Weddell Sea in the Antarctic, in the North Atlantic off Greenland and
in the Norwegian Sea.
The general dependence of the sea water density Pw(S, T, p) on the salinity,
S, temperature, T, and pressure, p, is called the equation of state for sea
water. There have been many attempts to establish the relationship Pw(S, T, p)
in the past (for more details see Dera, 1992) and the modern algorithm of
determination of density for given salinity, S, temperature, T, and pressure, p,
was developed by the international group of experts on standards (UNESCO,
1987). The expression for Pw(S, T,p) is rather complicated and it will not be
given here.
For convenience, in Appendix D a computer program, DIl, for calculating
density of water for arbitrary values of temperature, T, and salinity, S, is given.
Here, only some values of Pw (S, T, p), frequently used in the book, are given: