11
Descriptive Oceanography
in the oceans over 50 yr indicated that this water cycle has increased by 4%, apparently
due to surface warming of 0.5°C. This 8% increase/ degree of warming is the expected rate
on the amount of moisture the atmosphere can hold (Durack et al., 2012). The expected
increase in temperature of 2 to 3°C will probably continue the process in the oceans and
on land.
The typical vertical distributions of salinity in the Atlantic, Pacific, and tropics are shown
in Figure 1.13. There is a marked salinity minimum at 600 to 1000 m in the Atlantic.
This is due to the movement of subantarctic intermediate water to the north. The maximum near 100 to 200 m in the tropics is close to the top of the thermocline. It results
from water sinking at the tropical salinity maximum and flowing toward the equator. In
high latitudes, the surface salinity values are low owing to the melting of ice. The salinity generally increases with depth to 2000 m with no subsurface maximum. In low and
midlatitudes, the surface salinities are higher because evaporation is greater than rainfall.
In coastal waters with river runoff, there is a strong, rapid increase in salinity (halocline)
between the fresh river water and deep saline water. The salinity of deep water below
4000 m is quite uniform (34.6 to 34.9), while the temperature ranges from –1 to 2°C.
Sections of salinity for the Atlantic, Pacific, and Indian Oceans are shown in Figure 1.14
to Figure 1.16, respectively. The sections are in the intermediate waters (400 to 1500 m).
The Atlantic waters show the southern movement of North Atlantic deep water and the
remaining core of high- salt water between 20° N and 30° N that may be caused by the input
of Mediterranean waters. The North Pacific waters show the southern movement of subarctic intermediate water but no formation of deep water. In the Indian Ocean, no cold, deep
waters are formed in the north because of the Asian land mass. Salty intermediate waters,
however, are formed from the high- salinity waters coming from the Red Sea. A summary
of the temperature and salinity of the world ocean waters is shown in Figure 1.17.
33
35
37
0
1000
2000
3000
4000
High
Lat.
Low and
Mid Lat.
Atlantic
33
35
Depth (m)
Salinity
High
Lat.
Low and
Mid Lat.
Pacific
34
36
0
500
Tropics
Figure 1.13
Typical salinity profiles in the ocean.
Descriptive Oceanography
in the oceans over 50 yr indicated that this water cycle has increased by 4%, apparently
due to surface warming of 0.5°C. This 8% increase/ degree of warming is the expected rate
on the amount of moisture the atmosphere can hold (Durack et al., 2012). The expected
increase in temperature of 2 to 3°C will probably continue the process in the oceans and
on land.
The typical vertical distributions of salinity in the Atlantic, Pacific, and tropics are shown
in Figure 1.13. There is a marked salinity minimum at 600 to 1000 m in the Atlantic.
This is due to the movement of subantarctic intermediate water to the north. The maximum near 100 to 200 m in the tropics is close to the top of the thermocline. It results
from water sinking at the tropical salinity maximum and flowing toward the equator. In
high latitudes, the surface salinity values are low owing to the melting of ice. The salinity generally increases with depth to 2000 m with no subsurface maximum. In low and
midlatitudes, the surface salinities are higher because evaporation is greater than rainfall.
In coastal waters with river runoff, there is a strong, rapid increase in salinity (halocline)
between the fresh river water and deep saline water. The salinity of deep water below
4000 m is quite uniform (34.6 to 34.9), while the temperature ranges from –1 to 2°C.
Sections of salinity for the Atlantic, Pacific, and Indian Oceans are shown in Figure 1.14
to Figure 1.16, respectively. The sections are in the intermediate waters (400 to 1500 m).
The Atlantic waters show the southern movement of North Atlantic deep water and the
remaining core of high- salt water between 20° N and 30° N that may be caused by the input
of Mediterranean waters. The North Pacific waters show the southern movement of subarctic intermediate water but no formation of deep water. In the Indian Ocean, no cold, deep
waters are formed in the north because of the Asian land mass. Salty intermediate waters,
however, are formed from the high- salinity waters coming from the Red Sea. A summary
of the temperature and salinity of the world ocean waters is shown in Figure 1.17.
33
35
37
0
1000
2000
3000
4000
High
Lat.
Low and
Mid Lat.
Atlantic
33
35
Depth (m)
Salinity
High
Lat.
Low and
Mid Lat.
Pacific
34
36
0
500
Tropics
Figure 1.13
Typical salinity profiles in the ocean.