Marine Physics

Chapters 8, 9, 10

JUST COPY WHAT IS UNDERLINED!!!!!!

Influence of Currents on Climate

Pgs 9-20 to 9-21

 Currents play a critical role in how oceans affect weather and climate by transporting heat from warm areas to cool areas.



Currents moderate climates-

without the currents moving heat, the world’s climates would be more extreme.

Gulf Stream



One of the deepest surface currents carries heat

 Powerful, warm, swift  Starts at the Gulf of Mexico, crosses the Atlantic Ocean  Influences the east coast of N. America and the west coast of Europe  Moves warm air from over the Gulf Stream inland  Florida and N. Europe milder winters

California Current



S. California- mild climate due to the moderating effects of the Pacific Ocean

 The southerly current along the Calif. coast brings cool water from the north, keeping it cooler than it normally would be in the summer

Factors that Affect Direction and Patterns of Major Ocean Surface Currents

Pgs 9-3 to 9-5

#1 Wind

    Transfers energy to the water it blows across by the force of friction on the water’s surface Causes both surface currents and waves Ekman Transport/Spiral= Current moves to the right of the Wind at a 45 degree angle Major wind belts:  Trade winds  Westerlies  Polar Easterlies

#2 Land Masses



interrupt the flow of ocean currents creating closed circular current systems called gyres.

 Forces currents to turn

#3 Coriolis Effect

 influences the wind by giving it a circular flow pattern   the air deflects toward the right in the Northern Hemisphere and toward the left in the Southern Hemisphere- same with currents Christopher Columbus reached the new world thanks to the Coriolis effect  Note: If the Earth did not rotate and remained stationary, the atmosphere would circulate between the poles (high pressure areas) and the equator (a low pressure area) in a simple back-and-forth pattern. But because the Earth rotates, circulating air is deflected.

#4 Temperature

 Convection currents  Vertical movement of currents caused by temperature differences  Temperature divides layers of water  Deep sea vs. surface currents

Cause of the Coriolis Effect

 Earth’s rotation adds an apparent sideways motion to objects moving over the Earth’s surface.

Pilots need to correct their flight path based on the earth rotating under the airplane, which is the Coriolis effect.

In the inertial frame of reference (upper part of the picture), the black object moves in a straight line. However, the observer (red dot) who is standing in the rotating frame of reference (lower part of the picture) sees the object as following a curved path.

Tides

Pgs 10-3 to 10-24

What are Tides?

 Daily variations in the ocean’s level    The mean average tide occurs later each day by 50 min High  Low =6 hours 13 min.

High  High=12 hours 25 min.

 most noticeable at the shore, but affect the entire ocean.

Cause of Tides

      Result from the gravitational pull of the moon , and, to a lesser degree, the sun Earth is not a perfect sphere Time of the month Shape of the ocean basin  Large, wide basins have smaller tidal ranges  Narrow, shallow basins have larger tidal ranges Season Coriolis effect

Spring and Neap Tides

    Spring tides : occur during the full moon and new moon (they do not have anything to do with the season Spring) occur when the

Earth, the Sun, and the Moon are in a line

- every 2 weeks high tides are very high and the low tides are very low especially strong tides Spring Tide

    Neap tides occur during quarter moon phases occur when the gravitational forces of the Moon and the Sun are perpendicular to one another (with respect to the Earth). results in a smaller difference between high and low tides especially weak tides Neap Tide

Tidal Patterns & Currents

pgs 10-21 to 10-24

Tidal Pattern

 Diurnal tide   Single high and low tide daily Location: Gulf of Mexico  Semidiurnal Tide  Two “equal” high and low tides  Location: east coast of U.S.

 Mixed Tide  Two unequal high and low tides  Location: Pacific coast of U.S.

Waves

Parts of a Wave (draw figure)

Movement of Water in a Wave

 A wave is the transmission of energy through matter. •As the wave approaches, individual particles of water move in circular patterns as the wave’s energy moves through the water •Orbital motion

Tsunamis

 Sometimes reaching heights of 40 meters (120 ft.) or more,

tsunamis

are the most dramatic and destructive of waves.

Cause of Tsunamis

 A tsunami results from sudden water displacement caused by:   Landslide Iceberg falling into the sea from a glacier     Undersea volcanoes Earthquake Also called tidal waves Shallow water waves, fast moving