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Oceans and the Climate

Oceans and the Climate. By Chris Santomassi and Jake Coughlin. El Niño-Southern Oscillation . El Niño is a period of changes in pressure between Tahiti and Darwin and the warming of the central and East Pacific ocean

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Oceans and the Climate

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  1. Oceans and the Climate By Chris Santomassi and Jake Coughlin

  2. El Niño-Southern Oscillation • El Niño is a period of changes in pressure between Tahiti and Darwin and the warming of the central and East Pacific ocean • There is no clear cut cycle for when this happens but its general cycle has been noticed to occur every 3 to 8 years • What exactly causes the change in temperature are still unknown but are being researched • El Niño is believed to indirectly cause droughts and floods and drastically affect the fishing and agriculture industries

  3. La Niña • La Niña is the name for the cold phase of ENSO (El Niño-Southern Oscillation) when the water in the Eastern Pacific ocean cools and the trade winds get stronger. It is regarded as the opposite of El Niño and causes cooling rather than warming • During La Niña cyclone occurrences become more frequent and precipitation usually rises in the mid-west North America and in Asia • The mid-west and Canada are especially affected and during La Niña longer winters are recorded albeit, with more snow

  4. The ocean conveyor belt (Thermohaline circulation) • THC is the circulation of ocean currents on a very large scale caused by global density gradients • THC can alter climate because it circulates heat which is a form of energy and many different dissolved substances to different regions that would not normally contain them

  5. THC cont. • This system of fluctuating ocean waters is heavily affected by climate because cooler temperatures would make the water move slower and possibly cause it to become stagnant and stop circulating • A warmer climate, however would reduce how dense the water becomes and force it to circulate faster

  6. THC cont. • Water gains salinity when the rate of evaporation is high and salts become more diluted in water when there is an influx of freshwater which usually comes from melting ice or a river, lake pouring into the ocean • Water gains density when it loses heat, usually by traveling to higher altitudes and water loses density by gaining heat usually by moving to lower altitudes because more sun hits lower altitudes than higher ones due to the Earth’s axis • However, dense water masses are not always in this condition and need water masses of different densities to flow so that they can become stably stratified

  7. THC cont. • Water that is less salty floats over water that contains dissolved salts because the high salinity content has more mass because it fills “interstices” between water molecules, this floating is called stable stratification • However, dense water masses are not always in this condition and need water masses of different densities to flow so that they can become stably stratified

  8. THC cont. • The thermohaline circulation is instigated in the North Atlantic and Southern oceans where differences in temperature and salinity shift water masses. • Salinity also plays a role in thermohaline circulation because water that has a higher salinity content is more dense than fresh water • Salinity and temperature are the predominant driving force of deep water circulation

  9. THC cont. • The water moves due to heat because when it’s at the poles water is very cold and dense at which point it sinks and slowly travels to the poles • At the poles the water becomes less dense due to the heat and moves above the cold water to the poles • Thermohaline circulation moves water very slow, rarely moving faster than 10cm per second, it does transport massive amounts of water, having to move all the water in all of the oceans

  10. Coriolis effect • Caused by the movement of air while the Earth is rotating, and as a result the masses of air curve clockwise in the northern hemisphere and counterclockwise in the southern hemisphere • The circulating wind has a large effect on the surface of the oceans and can alter its course, deeper ocean currents are largely unaffected by wind and caused many early oceanographers to think that deep water remained static • Coriolis effect

  11. Coriolis effect cont. • As air moves from a high pressure system to a low pressure system in the Northern hemisphere the air masses are deflected to the right by the Coriolis effect, the Coriolis effect has the opposite effect in the Southern hemisphere where air is deflected to the left • The strength of the winds play a big role, as winds that are strong get deflected a lot while weaker winds are only slightly deflected.

  12. Coriolis effect cont. • The winds correlation to the poles is also especially relevant since winds that are closer to the poles will be deflected more than winds traveling at the same speed at the equator • The force of the Coriolis effect is zero at the equator • The Coriolis effect is linked to prevailing winds and the rotations of storms and in the hydrosphere where it affects the rotation of ocean currents

  13. Works Cited • "Consequences of rotation for weather." Csep10.phys.utk.edu. Web. 19 Oct. 2009. <http://csep10.phys.utk.edu/astr161/lect/earth/coriolis.html>. • "The Coriolis Effect: A (Fairly) Simple Explanation." Polar Satellite Meteorology at CIMSS. Web. 19 Oct. 2009. <http://stratus.ssec.wisc.edu/courses/gg101/coriolis/coriolis.html>. • "Coriolis Effect." Abyss.uoregon.edu Web Server. Web. 19 Oct. 2009. <http://abyss.uoregon.edu/~js/glossary/coriolis_effect.html>. • "Coriolis Force: an artifact of the earth's rotation." WW2010 (the weather world 2010 project):. Web. 19 Oct. 2009. <http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/fw/crls.rxml>. • "Coriolis Home Page." Physics at Oregon State University | Department of Physics. Web. 19 Oct. 2009. <http://www.physics.orst.edu/~mcintyre/coriolis/>. • "Global Warming and the Thermohaline Circulation: A negative feedback mechanism." San Jos&eacute; State University - Powering Silicon Valley. Web. 19 Oct. 2009. <http://www.sjsu.edu/faculty/watkins/thermohaline.htm>. • "Thermohaline circulation." Methane catastrophe. Web. 19 Oct. 2009. http://www.killerinourmidst.com/THC.html • . "Thermohaline Circulation: The Global Ocean Conveyor." Windows to the Universe. Web. 19 Oct. 2009. <http://www.windows.ucar.edu/tour/link=/earth/Water/circulation1.html>.

  14. Works Cited cont. • http://www.seisdeagosto.com/indica/wp-content/uploads/2006/05/Coriolis_effect14.png • http://www.windows.ucar.edu/earth/Water/images/thermohaline_circulation_conveyor_belt_big.gif • http://www.windows.ucar.edu/earth/images/currents1.jpg • http://www.windows.ucar.edu/earth/images/currents1.jpg • http://people.uncw.edu/tobiasc/GLY%20150/Abrupt%20Climate%20Change%20FAQ_files/conveyor-belt.gif • http://www.mbl.edu/news/press_releases/images/thermohaline_circulation.jpg • http://oceanography.earthednet.org/Mini_Studies/Deep_Ocean_Circulation/Deep_Ocean_Circulation_files/image009.jpg • http://www.liv.ac.uk/physocean/schematics/thc.gif • http://www.geology.um.maine.edu/ges121/lectures/19-ocean-conveyor/conveyor.jpg

  15. Recommended sites • Windows.ucar.edu • Encyclopedia Britannica • Atmos.uiuc.edu

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