GEOS 212 1st Edition Lecture 18 Outline of Last Lecture LECTURE 17 OUTLINE El Nino La Nina Hurricanes Review of dynamic aspects of oceans keep oceans well mixed o Waves surface layer Surface currents surface layer o Longshore currents surf zone o Coastal upwelling downwelling deep shallow water on local scale o Density currents driven by temperature and salinity 1 up at the equator from sun heat down at high latitudes turns in 100 years 2 Seasonal up in summer hemisphere down in winter hemisphere Driven largely by formation of ice sheets in winter Produces upwelling in opposite hemisphere controls migration patterns Slow 100 year rate and never turns in complete circle 3 Conveyor Belt current mixes all oceans turns in 1000 years Mixing time of the oceans 1600 years Impact of mixing time on marine life and society El Nino o patterns causes and consequences These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute o history back thru time o connection to global warming Pattern of hurricanes in profile and map view where up down Conditions needed for hurricanes warm water warm unstable air upper level winds not on equator Hurricanes typhoons and cyclones same storm in different oceans Hazards storm surge to 30 feet heavy rains over 1 per hour strong winds 74 to 200 mph Hurricane tracks Relation to global warming Outline of Current Lecture LECTURE 18 OUTLINE Tsunami Tides Global Warming Hurricane Movie Time Patterns and hazards Hurricane intensity through time increasing related to global warming Connections to El Nino La Nina Tsunami caused by up down movement of water most commonly earthquakes in subduction zones 2004 Sumatra earthquake tsunami 2011 earthquake tsunami in Japan 1700 Tsunami along the coast of Oregon Washington and California Next One Hazardous aspects of tsunami o Travel Fast 500 mph in deep water o Hard to track in deep water Need Early Warning System most in Pacific o Height builds in shallow water o Many waves o First one commonly a low water recedes o Largest one can be any one o Earthquake that causes tsunami can be far away o Affects huge area or ocean margin o Rare so people forget about hazards Tsunami from space impacts volcanic eruptions Tsunami heights for 2004 Indonesian EQ Evidence for large EQ Tsunami in 1700 in Pacific NW of U S When will the next one happen TIDES another dynamic process actually a wave that affects all oceans Main force gravitational pull from the moon creates bulge in earth Smaller force gravitational pull from the sun Earth Moon Sun system creates 28 day cycle Big range spring tides full moon new moon Small range neap tides half moon Tide chart below for 28 days spring neap tides full new half moon phases 2 Hi 2 Lo tides per GLOBAL WARMING Basics of Greenhouse affect Carbon Dioxide in the atmosphere Climate change Sea Level Change Bleaching of Coral Reefs Energy use climate change global politics Current Lecture
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