3. INTRODUCTION
Water exists in all three physical states of
matter : solid, liquid and gas
Determine many important oceanographic
phenomena, including :
- global pattern of oceanic and atmospheric
circulation, the growth and distribution of
marine organism
5. TEMPERATURE
Very important characteristic of seawater
The temperature of seawater is fixed at the
sea surface by heat exchange with the
atmosphere
The average incoming energy from the sun at
the earth’s surface is about four times higher
than at the poles
6. TEMPERATURE
The main physical mechanism is turbulent
mixing water by wind and wave
Establish a mixed surface layer that can be as
thick 200-300 m
Temperature declines rapidly throughout the
water column is call thermocline
It is measured in (Celsius (˚C), Kelvin (K)
and Fahrenheit (F))
7. TEMPERATURE
• Tropical are
permanently layer
(warm, less dense
surface water from cold,
dense deep water by
thermocline)
• Temperate regions
have a seasonal
thermocline, and pole
regions have none
9. SALINITY
Seawater is mixed of 96.5% pure water and 3.5%
others materials, such as salts, dissolved gases,
organic substances and undissolved particles
The salinity of surface seawater is controlled by the
balance between evaporation and precipitation
Unit is part per thousand = ppt = ‰, psu (practical
salinity units)
11. • Salinity map showing areas of high salinity (36‰) in green
• Medium salinity in blue (35‰)
• Low salinity (34‰) in purple
• North Atlantic, South Atlantic, South Pacific, Indian Ocean and
Mediterranean Sea to be a little high (green)
• Areas near Antarctica, Arctic Ocean, Southeast Asia, West Coast of North
America tend to be a little low (purple)
http://www.biosbcc.net/ocean/marinesci/02ocean/swcomposition.htm
North Atlantic
South Atlantic
South Pacific
Antarctica
Arctic Ocean
Indian Ocean
Mediterranean Sea
Southeast Asia
13. Pressure
Pressure is the force per unit area
A function of gravity, density and depth
The SI unit for pressure is the K Pa = 103 Pascal
Ocean pressure is usually reported in decibars where 1 dbar
= 104 Pa
In the ocean, the downward force of gravity is mostly balance
by an upward pressure gradient force, the water is not
accelerating downward (hydrostatic balance)
20. CONCLUSION
There are many physical parameter in seawater
Temperature, salinity, pressure and pH the most
important parameter in seawater
Understand variations in temperature, salinity,
pressure and pH and how they alter the chemical
and physical properties of the ocean
Can make prediction for the future
