Atmosphere, Oceans & Earth’s ClimateQuestions to ponderClimate controlsPowerPoint PresentationMilankovitch CyclesSlide 6Slide 7Slide 8The AtmosphereGreenhouse gases: CO2, Methane, Water Vapor and other compoundsSlide 11Slide 12Slide 13AlbedoSlide 15Atmospheric layersSlide 17But earth’s hydrosphere is critical in influencing climateOcean-atmosphere interactionRelationship of ocean-land-atmosphereOcean circulationEquatorial regions receive more sunSlide 23Why is the circulation as it is?Slide 25Thermohaline circulationSlide 27Slide 28Present circulation patternsAtmosphere Convection cells of heatSlide 31Earth spins = The Coriolis effectGeneral Global climate trendsSlide 34Slide 35Slide 36Slide 37Slide 38Slide 39Slide 40Slide 41Slide 42Atmosphere, Oceans &Earth’s ClimateLecture 25Questions to ponder•What are the controls of climate?•How does the ocean-atmosphere system interact?•What is the influence of plate tectonics upon climate?Climate controls•Solar luminosity•Orbital parameters (affecting angle of sun and distance)•Atmospheric composition (Greenhouse)•Physical materials of planet•Oceans•Other variables: biota; tectonicsMilankovitch Cycles•Variations ins earths orbital parameters•Eccentricity of Orbit around sun–100,00 year cycles•Axial Tilt–41,000 year cycles•Precession–23,000 year cyclesThe AtmosphereGreenhouse gases:CO2, Methane, Water Vapor and other compoundsAtmospheric Basics: review•The greenhouse effect •Radiant energy that is absorbed heats Earth and eventually is reradiated skyward.–Radiation is in the form of longwave infrared radiation.–Atmospheric gases, primarily H2O and CO2, are more efficient absorbers of longwave radiation.–This selective absorption, called the greenhouse effect, results in warming of the atmosphere.AlbedoClouds, vegetation, rocks, water and ice all contributeto albedoAtmospheric chemistryalso plays a roleAtmospheric layersBut earth’s hydrospherehydrosphere is critical in influencing climate•The ocean-atmosphere are coupled•Oceans = 77% of surface area•Water has high specific heat– Therefore retains heat•Ocean circulation influences atmosphere•Climate influences evaporation–Water vapor Greenhouse gas–Positive feedbackBUT, Clouds increase Albedo???Ocean-atmosphere interactionRelationship of ocean-land-atmosphereOcean circulation•Influenced by surface winds, but, also•Deeper cooler water v. warmer shallow water•Thermohaline circulation–Dense, salt water v. Less dense, less salty water–Dense cooler water v Less dense Warm waterEquatorial regions receive more sun•Due to earth’s “Tilt” on axis•Orbit around sun gives us seasonsOcean circulationWhy is the circulation as it is?•Continental placement•Coriolis effects•Atmosphere•Gradient between Cooler poles and warm equatorThermohaline circulationThermohaline Ocean CurrentsPresent circulation patternsAtmosphereConvection cells of heatSimple convection, but…..Earth spins= The Coriolis effect•Atmosphere develops circulation “cells” and preferred patternsGeneral Global climate trendsTropical Climates•High average T > 20oC•High precipitation - up to 2 m/yr•Development of rain forests•Large river systems•Deeply weathered soil profilesDesert Climates•Precipitation < evaporation–Total precipitation < 25 cm/yr•T varies from very hot to very cold•Slow rates of weathering•Erosion by wind•Evaporite depositsTemperate Climates•Range between 35o and 60o N & S of the equator•T ranges throughout the year•Precipitation may fall at any time•Large rivers may form•Moderate weathering & rich soilsPolar Climates•Regions N & S of 60o latitude•Average T < 10oC, below 0o most of the year•Low precipitation, often classified as deserts•Low rates of
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