Sarah RoseATOC 1060Midterm # 2 Ch 5- 11Chapter 5 Circulations of the oceans Ocean scale Atmosphere scale-ocean depth 5 km - tropopause 10 km-months to thousands of years - days to weeks (weather)-fast current, Gulf Stream 10 km/hr - fast winds, Jet Stream 100 km/hOcean is slower because water is heavier Atmosphere goes around whole globe, ocean confined by continents to ocean basins Ocean circulation-Wind driven surface flow, at surface, horizontal currents, wind powered-Thermohaline circulation, thermo(temperature) Haline(salt), density of sea water determined by temperature and salinity, driven by density, changes in density result in rising and sinking sea water, currents both horizontal and vertical Most incoming solar energy absorbs at surface (bottom of atmosphere/top of ocean)Top of ocean is heated, hot water rises (but it already at the top) no vertical motion, oceanis stratified meaning warm water near surface, cold water on bottomAtmosphere structure Troposphere (lowest) Stratosphere (2nd layer) Tropopause (boundary between them)Ocean is 2 layers- surface mixed layer (warm, thin) mixed by wind- deep ocean (cold, thick)Layers separated by thermoclineMoving ocean water = ocean current, Coriolis force turns thecurrent (all occurring with in top layer)Ocean Gyres, atmospheric circulation and Ekman spiral-large, planetary scale ocean circulations- main feature of wind driven surface circulation-not uniform-fast currents at western side of ocean basins (western boundary currents) ex Gulf Stream in N. Atlantic Thermohaline Circulation- less dense water on top, more dense bottom- warm = lighter, cold = more dense- fresh = lest dense, salt = more dense- no vertical motion - Near poles water gets cold and salty enough to sink to bottom (Bottom-water formation) only occurs near Antarctica- Sinking results in rising water somewhere else, overturning of ocean- Very slow timescale, 1000 years Circulations coexists - wind-driven surface circulation and thermohaline circulation both occur- a parcel of water is affected by bothOcean energy transport, ocean carries about 1/3 poleward heat transportChanges in Earth system’s equator to pole heat transport would affect the atmosphere AND ocean If polar ice caps melt- decrease salinity, seawater because less dense near poles- less dense water moves faster when pushed by winds, faster gyres- less dense water won’t sink, slows thermohaline circulation- small changes in thermohaline circulation can have large effects onclimateWind driven surface currents would be affected and:- stronger pressure systems, poles warms more then tropics weakenatmospheric circulation, stronger storms, faster winds/currentsEl Nino (warm event)-Regional to global scale, more climate then weather-coupled atmospheric-ocean phenomenon-tropical pacific region-affects weather around the globe-predictable-atmospheric component is call Southern Oscillation-El Nino Southern Oscillation ENSO (just el nino)Components of ENSO-East west tropical atmospheric circulation, Walkercirculation-Ocean surface temperatures, warm pool-Depth of thermoclineENSO stages-growth/shrink of Pacific Warm Pool (very large)-warm pool stores large amount of energy, water has highheat capacity-when El Nino ends, energy is released-Energy flow from Equator-Pole changes during ENSO event-affects global weatherLa Nina (cold event)-evaporations in tropical pacific would go downSUMMARY CH 5Vertical structure consists of warm shallow (500 m) mixed- layer atop cold deep ocean, separated by thermocline Two coexisting ocean circulations • Wind-driven surface circulation • Thermohaline (overturning) circulation Wind-drive circulation forms anti-cyclonic gyres in all ocean basins Western boundaries of basins have fast narrow currents Thermohaline circulation has sinking in N. Atlantic and near Antarcti• Return flow has rising water in Indian and Pacific oceans El-Niño is a climate phenomena with timescale 2-10 years, predictable months in advance- Coupled atmosphere-ocean phenomena: East-West winds,precipitation, sea surface temperatures, thermocline depthCentered in Tropical PacificChapter 6 The CryosphereCryosphere, the components of the Earth system composed of frozen waterClimate affects: Albedo, Methane (greenhouse gas) and permafrostComponents of cryosphere- Ice sheets, ice on land- Ice shelves, ice floating on waterMelting ice shelves does not change sea levelSnow cover-determined by snowfall and melt-affected by planetary albedoPermafrost-permanently frozen groundmelting permafrost affects local ecosystems, releases greenhouse gases -large reservoir of carbon (carbon in permafrost = two times currently in atmosphere)-releases carbon dioxide or methane-1/3 to 2/3 may melt by 2200 p, permafrost amountg, atmospheric greenhouse gas concentrationT, temperatureSGlaciers and ice sheets move-accumulate from snowfall, melt (ablation)-are shrinking, results in rise of sea levelSea Ice-seasonal cycle over months-shrinking on decadal time scale-fluctuations on annual time scaleSea ice and atmosphere-ocean heat flux-winter arctic air (below freezing)-Arctic sea water (near freezing warmer then air)-Sea ice insulates oceanComponents-s, sea ice concentration-T, air temperature-h, heat flux from ocean to atmosphere sea ice melts increasing heat flux from warmer ocean to colder atmosphereSUMMARY CH 6Cryosphere has significant climate impactsPermafrost: has carbon stored over thousands of years. melting will release this carbon to the atmosphere in decades to centuries, positive feedback Sea ice and land ice are shrinking: observed fact Two positive feedbacks• Ice-albedo• Atmosphere-ocean heat flux Large uncertainties about what will happen and how fast. Chapter 7 Circulation of the solid Earth: Plate TectonicGeography affects climate, size of continents, shape of ocean basins, land/sea contrastLong term cycling of chemicals, carbon cycle, volcanoes, erosion, uplift, burialSeismic waves, knowledge of Earth’s interior from seismic waves, can measure time for waves to travel from earthquake to seismograph, speed depends on material Earth’s Layers-Crust, continental and ocean-Mantle, upper and lower-Core, inner and outerSea floor spreading, ocean ridges, deeptranches, date sea floor by magneticreversal Continental drift, continents move on 10-100Myr timescaleStructural layers-Seismic wave-based layers, crust, mantle, core-Lithosphere, rigid (crust and top part of upper mantle) divided into about