Physical Oceanography The Oceans Sea Water Ocean Movements Chap. 15 Objectives The Oceans – 15.1 identify methods used by scientists to study Earth’s oceans discuss the origin and composition of the oceans. describe the distribution of oceans and major seas Introduction
What are some useful features of oceans?
Measured depth, water temperature, fauna, current, and other data. First measured Mariana trench (26,890 ft.)
Used sonar to map undersea topography
A sonar signal travels about 1500 m/s in ocean water. If it takes 6 seconds for a signal to return to the ship after it is emitted what is the distance to the ocean floor?
NASA satellite that measures ocean data
This is also called the hydrosphere
Where is the Earth’s water found?
Due to melting of glaciers and tectonic forces altering sea floor.
A measure of the dissolved salts in water.
Density of fresh water is 1.00 g/cm3
Can be as low as -2ºC
The ocean is completely dark at depths > 100 m
Periodic movement that carries energy from one place to another.
The peak of a wave
Lowest part of a wave
Distance between successive wave crests (or troughs)
Depends on wind speed, wind duration, and fetch.
More friction with ocean bottom causes waves to slow.
The tops of the waves collapse forward because the bottoms are being slowed
Periodic rise and fall of sea level.
Highest level to which water rises (a bulge of water)
Lowest level water rises (caused by lack of water)
Caused by topography and latitude
Characterized by __ high tides each day
Have one pronounced high tide and one _____ high tide
Characterized by one ____ ____ each day
This is because of the greater distance between Earth and the sun (compared to Earth and the moon)
Move bottom water according to temperature and salinity differences
Driven by surface wind.
Trade winds, prevailing westerlies, polar easterly winds. Coriolis effect alters directions
Circular surface ocean currents
Movement of cold water upward as surface water is blown by offshore winds