MIDTERM 1 STUDY GUIDELECTURE 2Weather (day to day description of the atmosphere for a specific place, time, and date) VS.Climate (how atmosphere usually behaves in that region)Fronts•Active areas where air masses of different temps meet•Types:•Cold: cold air moves in and forces warm air to rise (clouds, heavy rain, storms)•Warm: warm air moves in and gently rises over cold air (fair weather, some clouds, light rain)•Stationary: •Occluded: Atmospheric Composition and Evolution•Composition:•78% nitrogen (N2)•20% Oxygen (O2)•2% Argon (Ar & other trace gases CO2, CH4, O3 that are highly reactive)•Evolution: •Early atmosphere (hydrogen (H), Helium (He), methane (CH4), & ammonia (NH3))•Volcanic Eruptions (released H20, CO2, & NH2)•H2O combined with CO2 through photosynthesis (created O2)•Molecular Oxygen (O2) combines with single oxygen (O) (creates O3-filters out harmful UV rays, allowing growth of plants and sustains animals)•Plants decay under water (creates Methane (CH4))•Greenhouse gas (traps radiation)•Breaks down in stratosphere to form water•Cloroflurocarbons (CFC) •Greenhouse gas •Breaks down in stratosphere to form CL (destroys O3)•Ocean salt particles, volcanos, fires, human activity (creates Aerosols, small particles in the atmosphere)•Scatters radiationback to space,cooling earths sur-face•Sometimes trapsradiation, warmingatmosphereCarbon Dioxide Cycle•Exchange of CO2 be-tween land, atmosphere andoceansHydrologic Cycle•Continuous exchange of water between land, atmosphere and oceans•Sun is the main energy source•Water is present in oceans, lakes, rivers, glaciers, clouds, etc.Atmospheric PressureAtmospheric Layers•Troposphere•Lowest layer, temp decreases as height increases, most weather occurs here•Stratosphere •Temp increases with height, high concentrations of ozone, little mixing of air•Mesosphere •Temp decreases with height•Thermosphere •Very low atmospheric mass, lots of radiation, not many particles to absorb itLECTURE 3Specific Heat & Energy Transfer•Specific Heat is the amount of heat required to raise the temp of 1g of a substance by 1°C•Energy Transfer •Conduction: transfer of heat through matter contact•Mainly earths surface•Air is a poor conductor•Convection: transfer of heat through vertical mass movements•Only in liquid (including atmosphere)•Energy at surface is transferred to upper levels•Results in vertical atmospheric circulation patters•Advection: horizontal movement of air•Includes fronts•Radiation: energy from sun to earth through electro-magnetic waves•Latent heat: heat is released & absorbed during phasechanges (melting/evap-latent heat taken in, and freezing/condensation-latent heat is released)The weight of air above a certain pointFunction of temperature and densityDecreases with height (changes with altitude)Measured with a barometerAvg sea level pressure = 1013 mbWeather tends to move along constant pressure linesTemperature ScalesFarenheit, Celcius, KelvinDefined by upper & lower calibration (fixed) points-273 K = lowest possible temp0°C=melting (freezing) point of H20100°C = boiling point of H20Radiation LawsBlack body absorbs and emits radiation at all wavelengthsWein’s Displacement Law: wavelength of max emission from a black body is indirectly proportional to temperatureStephan Boltzmann Law: total energy radiated by a black body is proportional to the 4th power of temperatureRadiation vs. Earth•Earth has a 23 ½ degree tilt•Northern Hemisphere •NH points away from the sun in the winter (less radiation at the surface per unit area)•NH points towards the sun in the summer (more radiation at the surface per unit area)•Reason for season has nothing to do with the suns distance from the earthPoles are Cold and Equator is Hot•Solar zenith angle at the poles is greater than the solar zenith angle at the equator•Angle between the Zenith (point on the surface) and the sun•Larger angle = more atmosphere to travel through•Poles receive less direct sunlight (less radiation per unit area)•High Sun is in the summer months (heat up quicker), Low Sun is in the winter monthsDaylight is longer during the summer and shorter during the Winter•Because of earth’s 23 ½ degree tilt & zenith angle differences•Summer Solstice (June): north pole is towards sun (full sunlight all day)•Winter Solstice (December) : north pole is away from sun (full darkness all day)•Summer > winter = NH days get shorter and shorterIncoming Solar Radiation•51% radiation reaches the surface•(25% is direct, 26% is scattered by the atmosphere before reaching surface•31% is reflected back to space•19% is absorbed by gases, aerosols, and clouds•(increased temperatures, absorbing gases include O2, O3, & water vapor)•Absorption is when the atmosphere absorbs radiant energy, molecules move quicker, temp riese•Scattering produces light, shorter waves (blue/violet) scatter better than (orange/red) skyis blue!•@ sunset, light goes through more atmosphere, shorter waves scattered away, only see long•Reflection is when a fraction of energy is reflected by surface, brighter surface, more it reflects•Albedo = % of radiation a surface reflects (snow has high, asphalt has low)•Darker surface = absorption > reflection = lower albedo•Average earth albedo = ~30%Global Energy Balance•Average net energy balance = energy in vs. Energy out•Global average: incoming radiation = outgoing radiation (thermal equilibrium)•@ Equator there is a surplus of energy (more incoming radiation than outgoing)•@ Poles there is a deficit of energy (more outgoing radiation than incoming)•B/c of convection, heat is transported from the equator towards the poles (so poles don’t get colder and equator doesn’t get warmer)LECTURE 4Greenhouse Effect•Carbon dioxide, water, & methane•Absorbs outgoing radiation emitted from the earths surface•Take radiation and reflect it or redirect it through scattering back to space•When its reflected back to surface, it heats the earthAir Temperature•Daily Measurements•Mean Temps = avg of hourly (24) measurements & avg of max and min temps for the day•Daily Range = max - min•Monthly•Mean = avg of daily means for the month•Annual•Mean = avg of monthly means for a year•Range = max monthly mean - min monthly meanWhat Controls Daily