Lectures week 5.

Tuesday:

Ocean currents are mostly driven by winds, although density changes due to temperature differences and salinity differences can also be important. The rotation of the earth influences the motions of both the atmosphere and the oceans through the Coriolis effect. Recall that the Coriolis force is to the right for an object (air mass or water mass, for example) in the northern hemisphere, and to the left in the southern hemisphere. Cold air formed at the poles is deflected to form polar easterly winds. Around Antarctica, these create an upwelling zone where the currents they cause meet the current caused by the Antarctic circumpolar current driven by the southern westerly winds. This upwelling accounts for the high biological productivity around Antarctica. Try to explain ocean current patterns to yourself.

Thursday:

Ocean waves are caused by earthquakes, storms, moving ships, or any other disturbance to a "flat" sea surface. They can travel great distances if they are very long, resulting in surf. Waves caused by the moon and sun are called tides. Waves caused by earthquakes that involve displacement of large sections of the sea floor are called Tsunamis.