Slide 1Slide 2Slide 3Two main points in this figureSlide 5MethaneSlide 7Slide 8Slide 9Slide 10Slide 11Slide 12Energy Balance VideoEnergy BalanceSlide 15UnitsUnit ReviewSlide 18Slide 19Slide 20Slide 21Slide 22Slide 23Group DiscussionSlide 25Slide 26Slide 27Slide 28Slide 29Slide 30Slide 31Video Global Energy Balance -AlbedoVideo Global Energy BalanceSlide 34Slide 35Slide 36Slide 37Slide 38Slide 39Slide 40Slide 41Slide 42Slide 43Conclusion from NASA MODIS Albedo (namely, the last few slides)METR112 Global Climate Change -- Lecture 2 Energy BalanceProf. Menglin JinSan Jose State UniversityReview Lecture 11. Two critical increases – global mean surface temperature and greenhouse gases2. One key concept – greenhouse effectChange in surface temperature in 20th centuryTwo main points in this figure•Global mean surface temperatures have increased 0.5-1.0°C since the late 19th century •The 20th century's 10 warmest years all occurred in the last 15 years of the centuryNote: 1. why is global mean? 2. what is surface air temperature? (see next few slides)The “Keeling curve,” a long-term record of atmospheric CO2 concentration measured at the Mauna Loa Observatory (Keeling et al.). Although the annual oscillations represent natural, seasonal variations, the long-term increase means that concentrations are higher than they have been in 400,000 years. Graphic courtesy of NASA’s Earth Observatory.MethaneGreenhouse gases (important!)CO2 CH4N2O (Nitrous Oxiode, so called “laughing gas”)CFCO3H2Oby the early 21st century, N2O had become nearly as important a greenhouse gas as methane. Their best guess was 0.7°C for N2O, and 0.3°C for methane. Wang et al. (1976).The Greenhouse Effect (Important concept)Energy of EarthBALANCEDBALANCEDBALANCEDBALANCEDhttp://earthguide.ucsd.edu/earthguide/diagrams/energybalance/index.htmlUseful link on energy balance:Energy Balance Videohttp://www.met.sjsu.edu/metr112-videos/MET%20112%20Video%20Library-wmv/energy%20balance/Earth’s Energy Budget.WMVEnergy Balance•Assume that the Earth’s surface is in thermodynamic equilibrium:•Thermodynamic Equilibrium: –The flow of energy away the surface equals the flow of energy toward the surface SurfaceAverage surface temperature = 15°C100% of the incoming energy from the sun is balanced by 100% percent total energy outgoing from the earth. incoming energy from the Sun = outgoing energy from the Earth.UnitsUnits•Our class will use both English and Metric unit systems.•Most important:–Distance (kilometres and miles) –Temperature (ºC and ºF)•Conversions:1.6 km = 1 mile; 1 km = 0.61 miles(9/5 x ºC) + 32 = ºF(ºF – 32) x 5/9 = ºCUnit ReviewUnit Review•What is the current temperature in ºC? (current temp = 90F)•California is about 800 miles long (from Oregon to Mexico). How many kilometers is that?•If you were told that the average high temperature in Sydney Australia at this time of year is 26ºC, what temperature is that in ºF?Class participationThree temperature scales:Three temperature scales:•KelvinKelvin•CelsiusCelsius•FahrenheitFahrenheit•What does temperature What does temperature mean physically?mean physically?•What does 0What does 0°° K mean? K mean?°K= °C+273°K= °C+273Answer: statistical averaged speed of air moleculesTemperaturethe degree of hotness or coldness of a body or environment (corresponding to its molecular activity) Temperature is one of the principal parameters of thermodynamics. On the microscopic scale, temperature is defined as the average energy of microscopic motions of a single particle in the system per degree of freedom. On the macroscopic scale, temperature is the unique physical property that determines the direction of heat flow between two objects placed in thermal contact. Cold temperatureWarm temperatureJust an example, could be higher or lowerhttp://en.wikipedia.org/wiki/Solar_radiation#Climate_effect_of_solar_radiationsince the Earth is much cooler than the Sun, its radiating energy is much weaker (long wavelength) infrared energy. energy radiation into the atmosphere as heat, rising from a hot road, creating shimmers on hot sunny days. The earth-atmosphere energy balance is achieved as the energy received from the Sun balances the energy lost by the Earth back into space. So, the Earth maintains a stable average temperature and therefore a stable climate. http://www.srh.noaa.gov/jetstream//atmos/energy.htmGroup DiscussionIf you go camping with friends. The first day and night are clear and the 2nd day and night are cloudy.• Which day is cold?•Which night is cold?•Why?The Transfer Of Heat: 3 waysThe heat source for our planet is the Energy from the sun is transferred through space and through the earth's atmosphere to the earth's surface. Since this energy warms the earth's surface and atmosphere, some of it is or becomes heat energy. There are three ways heat is transferred into and through the atmosphere:radiation conductionconvectionsunRadiation is the transfer of heat energy through space by electromagnetic radiation.All cell phones, once powered on, emit certain amounts of electromagnetic radiation in the microwave radio frequency range.eport that associated prolonged mobile phone use and exposure to differing amounts of cellular phone radiation to brain tumors, cancer, stress, headaches, cognitive problems, and sleep disordershttp://heatexchanger-design.com/2011/03/17/radiation-2/The flow of heat by conduction occurs via collisions between atoms and molecules in the substance and the subsequent transfer of kinetic energy.Take a look: http://www.nationmaster.com/encyclopedia/Image:Translational-motion.gifFig. 2-2, p. 30Convection is the transfer of heat energy in a fluid. Cumulus clouds indicates where upward convection currents areOther example: In kitchen liquid boilingWhat forms you see here to transfer heat?Video Global Energy Balance -AlbedoSee video below to help your understandinghttp://www.met.sjsu.edu/metr112-videos/MET%20112%20Video%20Library-wmv/energy%20balance-albedo/a. Ice Albedo .wmvb. Clouds albedo.wmv -observe cloud and surface albedo, also observe shortwave radiation and lonwave radiationc. Globe Ice Albedo.wmvVideo Global Energy BalanceWhat is the source of global energy? What is the difference between icesheet and ocean in terms of their reflections on incoming solar radiation?Arctic sea ice coverage, 1979 and 2003, all students need to read NASA