32
Chemical Oceanography, 4th Edition
in the Indian Ocean are shown in Figure 1.39. The equatorial waters have a salinity of 34.9 to
35.2 and are located north of 10° N at a depth of 100 to 2000 m. The central waters are similar to
South Atlantic central waters (800 to 1000 m). The Antarctic intermediate waters are characterized by the usual salinity minimum. They are formed at the Antarctic convergence as in the
Atlantic and Pacific. The deep waters in the Indian Ocean have temperatures of 1 to 3°C and
salinity of 34.6 to 34.8. This deep water has properties similar to the Pacific deep waters and
is the remnant of North Atlantic deep water. The Antarctic bottom water in the South Indian
Ocean has properties similar to the bottom waters formed in the Atlantic and Pacific.
In the northern and western Indian Ocean, a warm saline water mass flows out of the
Red Sea to a depth of 1000 to 1500 m. The sill depth of the Red Sea is about 125 m. Since
evaporation exceeds precipitation in the Red Sea and there is little river runoff, the salinity
becomes very high (42.5), as does the temperature. This salty water sinks and flows out of
the Red Sea across the sill. The water that leaves the Red Sea has different properties than
deep Red Sea waters. Inside the sill, the temperature is 24°C, and salinity is 39.8; outside
the sill, the temperature is 15°C, and salinity is 36. Surface inflow occurs similar to the
Mediterranean Sea.
1.4.5 arctic and adjacent Seas
The surface circulation in the Arctic and adjacent seas is shown in Figure 1.40. The
Norwegian Current is a continuation of the North Atlantic current that turns north and
flows into the Norwegian Sea. The East Greenland Current flows southwestward along
the Greenland coast. It is composed of waters from the Arctic Sea, with some mixing with
Norwegian Current waters. The speed of the current is about 30 cm s –1 . The ridge from
Greenland to Scotland is 1000 m and prevents deeper Atlantic water from entering the
Norwegian and Arctic Seas. The East Greenland Current carries ice from the Arctic into
the North Atlantic.
In the Norwegian and Greenland Seas, the surface waters consist of the Greenland
gyre (above 1500 m, t = –1.1 to –1.7°C and S = 34.86 to 34.90; below this depth, S = 34.92
and t <1.1°C). The deep waters of the Norwegian gyre have the same salinity, but the
20
34
35
Salinity
36
26
27
28
1000 m
100 m
R e d S e a
Ind.
3000 m
800 m
Ant. Bot.
A n t .
I n t e r .
S u b - A n t
Indian
Ocean
10
Temperature °C
0
I n d .
Eq ua t.
C e n t r a l
Figure 1.39
The T- S diagrams for the Indian Ocean.
Chemical Oceanography, 4th Edition
in the Indian Ocean are shown in Figure 1.39. The equatorial waters have a salinity of 34.9 to
35.2 and are located north of 10° N at a depth of 100 to 2000 m. The central waters are similar to
South Atlantic central waters (800 to 1000 m). The Antarctic intermediate waters are characterized by the usual salinity minimum. They are formed at the Antarctic convergence as in the
Atlantic and Pacific. The deep waters in the Indian Ocean have temperatures of 1 to 3°C and
salinity of 34.6 to 34.8. This deep water has properties similar to the Pacific deep waters and
is the remnant of North Atlantic deep water. The Antarctic bottom water in the South Indian
Ocean has properties similar to the bottom waters formed in the Atlantic and Pacific.
In the northern and western Indian Ocean, a warm saline water mass flows out of the
Red Sea to a depth of 1000 to 1500 m. The sill depth of the Red Sea is about 125 m. Since
evaporation exceeds precipitation in the Red Sea and there is little river runoff, the salinity
becomes very high (42.5), as does the temperature. This salty water sinks and flows out of
the Red Sea across the sill. The water that leaves the Red Sea has different properties than
deep Red Sea waters. Inside the sill, the temperature is 24°C, and salinity is 39.8; outside
the sill, the temperature is 15°C, and salinity is 36. Surface inflow occurs similar to the
Mediterranean Sea.
1.4.5 arctic and adjacent Seas
The surface circulation in the Arctic and adjacent seas is shown in Figure 1.40. The
Norwegian Current is a continuation of the North Atlantic current that turns north and
flows into the Norwegian Sea. The East Greenland Current flows southwestward along
the Greenland coast. It is composed of waters from the Arctic Sea, with some mixing with
Norwegian Current waters. The speed of the current is about 30 cm s –1 . The ridge from
Greenland to Scotland is 1000 m and prevents deeper Atlantic water from entering the
Norwegian and Arctic Seas. The East Greenland Current carries ice from the Arctic into
the North Atlantic.
In the Norwegian and Greenland Seas, the surface waters consist of the Greenland
gyre (above 1500 m, t = –1.1 to –1.7°C and S = 34.86 to 34.90; below this depth, S = 34.92
and t <1.1°C). The deep waters of the Norwegian gyre have the same salinity, but the
20
34
35
Salinity
36
26
27
28
1000 m
100 m
R e d S e a
Ind.
3000 m
800 m
Ant. Bot.
A n t .
I n t e r .
S u b - A n t
Indian
Ocean
10
Temperature °C
0
I n d .
Eq ua t.
C e n t r a l
Figure 1.39
The T- S diagrams for the Indian Ocean.