Lecture6_2011.keyr

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Unformatted text preview: http://scrippseducation.ucsd.edu/faculty/driscoll/water Water Cycle Evaporation, Precipitation, and Atmospheric circulation Tectonics and Orographic Effects Hydrologic Cycle - is responsible for the largest movement of a chemical substance on our planet. Water movement determines climatic patterns, plant growth, heat energy transfer, erosion rates, and rates of rock weathering • evaporation (latent heat input) about 500,000 km3 enough to cover the earth’s entire surface to a depth of about 1 m • transportation (water vapor and liquid - transports sensible heat) • precipitation (latent heat relase) • infiltration (recharge groundwater) • transpiration (plants release into atmosphere) El Nino Southern Oscillation (ENSO) El Nino conditions are only one end member of a system oscillating between two extremes. When the pressure differential is low (low SOI) the trade winds slacken and the West Pacific Warm Pool runs “downhill” towards the east. This results in warmer waters and a deeper thermocline in the east, as well as eastward movement of the region of precipitation. The opposite conditions (La Nina) result from an increased pressure differential (high SOI). Note thermocline position along S. America Eureka, CA http://www.youtube.com/watch?v=AEoHz56jWGY Atmospheric Circulation Cells also explain variations in precipitation with latitude: (Hadley, Ferrel) 0 degrees warm air rises, condenses- rain (low pressure) 30 degrees dry air descending and warms- deserts (high pressure) 60 degrees rain (low pressure) 90 degrees desert (high pressure) Then Add continents 1. physical barriers- deflect the winds 2. thermal effects 1. Effect of continentsLocation of high and low pressure systems varies with season as land heats and cools more than the sea • sea breezes • monsoons Southern hemisphere more zonal circulation due to less land Orographic effects- rain shadow Arid Region (desert) down stream of mountains 1. Effect of continentsLocation of high and low pressure systems varies with season as land heats and cools more than the sea • sea breezes • monsoons Southern hemisphere more zonal circulation due to less land Orographic effects- rain shadows Plate Tectonics Tectonic Signatures on Continental Margins Scripps Institution of Oceanography Plate Tectonics Scripps Institution of Oceanography Atmospheric and Ocean Circulation: The Role of Plate Tectonics Isthmus of Panama • Global Circulation •~4.6 Ma Landscape and seascape evolution record the complex interplay between tectonics, climate, and sediment supply. Control Gateways for circulation Plate Tectonic Theory Divergent Ridges and Rifts Convergent trenches and mountain belts Translational Strike slip faults and transform faults • The outer shell of the earth, the lithosphere, is made up of 12 large, rigid plates. • The rigid plates predominantly deform along their edges • Three major types of plate boundaries http://videos.howstuffworks.com/hsw/26561-earth-scienceplate-tectonics-video.htm R idges Fast Slow http://www.whoi.edu/oceanus/viewArticle.do?id=27286 Translational Boundaries Development and Evolution of the San Andreas Fault 1906 Earthquake in San Fran left 250,000 homeless Folding caused by movement along the San Andreas at Avenue S on the SR-14 Freeway. Strata is the Pliocene Anaverde Formation, which is mostly comprised of weak shales and siltstones. San Luis Obispo County California Convergent Boundaries Ring of Fire Earthquakes Earthquakes Tsunamis, though rare, occur mostly in the Pacific Ocean. The huge waves of the tsunamis moves across the ocean vary rapidly and are capable of destroying any coastal town or village. Tsunami is a Japanese word meaning harbour wave. Most tsunamis start around the 'Ring of Fire' that is a chain of eruptive volcanoes. Tsunamis sometimes start on land after an earthquake. Convergent Boundaries ...
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