The Atmosphere 01 30 2014 Structure of the Atmosphere Atmospheric Pressure Atmospheric Composition CO2 CH4 H20 CFC s Aerosols o Temperature Anomaly change in temp relative to mean temp If climate is changing how will this affect weather Land Weather and Climate 70 of earths surface is water oceans help regulate global temperatures oceans not distributed equally over surface northern hemisphere will have most variation in weather not only affects surface but atmosphere land surface will create instabilities in wind flow land ocean bound will as well Weather Maps Front boundary b n two differing air masses o Cold cold air replacing warm o Warm warm air replacing cold o Stationary border b n to different fronts neither front strong enough to move the other o Occluded cold front overtakes warm front Atmospheric Temperature Profile Temperature decrease as go higher up in atmosphere Not as close to surface Air is thinner Air decreases to a point than warms up again Troposphere colder as increase MOVE AWAY FROM SURFACE o Tropopause point at which stop decreasing Stratosphere warmer as increase OZONE o Stratopause point at which stop increasing Mesosphere colder as decrease LEAVE OZONE o Mesopause point at which stop decreasing Thermosphere warmer as increase SUN Pressure Inches of mercury Multiply inches of mercury by 33 865 to convert to mb As pressure drops the barometer is said to be falling Generally means severe some sort of weather is coming Ideal Gas Law Pressure X volume constant X temperature Pressure density X temperature X constant Density pressure temperature X constant Atmospheric Composition Major nonpermanent gas Nitrogen Oxygen Argon Variable Gas Water vapor CO2 Methane Nitrous oxide Ozone CFCs Carbon dioxide cycle CO2 decrease Methane Water Cycle More sources than sinks CO2 has a variety of natural and anthropogenic sources As plants grow they absorb CO2 from the air Levels of atmospheric Methane is lost mainly by chemical reactions in the atmosphere TPW total precipitable water Difficult to say if there is a trend in atmospheric water Held pretty steady since the 1990s The water cycle plays a major role in drving weather and climate Powered by solar energy more sunlight more evaportation Clouds reflect incoming solar energy cool surface CFCs Chlorofluorocarbon Increase in levels since 1940 Great Acceleration No natural sources of CFC s represent a family of gases Chemically engineered Ozone deterriates 1970s US bans decrease in CFC levels 1990 Montreal Protocol extreme decrease ozone repairs itself Very tiny particles measured in microns Smog smoke from fires viruses cloud particles bacteria human Aerosols hair beach sand Aerosol Observations satellite o Cloud Aerosol Lidar and Infrared Pathfinder Satellite Observation CALIPSO o Can capture cloud formations volcanic explosions etc April 17 2012 CALIPSO captured image of the Eyjafjallaj kull ash cloud after eruption 01 30 2014 The Energy Cycle Temperature Scales Celsius Centigrade scale Melting point of water is 0 degrees C Boiling point is 100 degrees C Melting point of water is 32 degrees F Boiling point is 212 degrees F Fahrenheit Scale Kelvin Similar to Celsius Add 273 15 to Celsius to determine Kelvin Coldest temperature ABSOLUTE ZERO is 0 K Never goes negative Specific Heat The specific heat of a substance is the amount of heat required to increase the temperature of 1 gram of the substance 1 degree C Energy Transfer Common Energy Terms o Energy needed to raise the temperature of 1 gram of water 1 Calorie degree C o Dietary calorie 1000 calories Joule o 0 2389 calories o conversion purposes Watt o Amount of energy transferred over time o 1 watt 1 joule second o 100 watt light bulb 100 J s 5 major energy transfer processes conduction molecule o Air is not a good conductor o Metals are excellent conductors o Most important at Earth s surface Convection o requires contact energy transferred from molecule to o Energy transferred by movement of fluids in science air is considered a fluid o Surface energy transferred upward by convection Advection Hot air rises o Horizontal movement of air Latent Heating o Amount of heat absorbed or released during a phase change o Solid liquid or gas describes phase of material o Does not always mean change in temperature o WATER CYCLE Endothermic exothermic reactions Ice vapor energy taken from environment Vapor ice energy released from environment Radiative processes o Radiative Heat heating due to electromagnetic radiation o Different from nuclear radiation Light Energy Electromagnetic Spectrum o Length of one wave lambda Wavelength Amplitude Frequency Radiation Laws Stefan Boltzmann Law o Height of the wave 1 2 distance from peak to trough o The number of times the wave peaks in 1 second Total amount of energy emitted by a blackbody o E emitted radiation o e emissivity E eoT4 o o 5 67X10 8 o T temperature K EMISSIVITY tells us how well an object absorbs and reemits energy o 1 everything gets absorbed and reemitted o 0 nothing is absorbed Weins Displacement Law The wavelength at which the energy spectrum reaches maximum o WLmax um 2900 um K T K o T K 2900 um K WLmax um If you know the temperature you can find out the wavelength and vice versa Electromagnetic Spectrum The energy from the sun peaks at 0 5 um visible portion of the spectrum shortwave radiation The energy from the earth Peaks at 10 um Longwave radiation Infrared thermal portion of the spectrum Explains why we can see the sun and the earth for us doesn t emit visible light Albedo the percentage of radiation that is reflected off of a surface 100 means everything is reflected snow has an abledo of 90 Earth s albedo appx 30 Plays a vital role in determining the energy balance of the land atmosphere Seasons and Surfaces affect on surface heating Solar zenith angle The angle between the sun and the point directly over head The intensity of light reaching the surface decreases as the sun lowers in the sky o As SZA increases INTENSITY decreases Why does it change o Latitude round Radiative Forcing Higher latitudes experience shorter days in winter o Colder less solar energy hits directly o Tilt of earth away Higher latitudes experience longer days in summer o Warmer more solar energy hits directly o Tilt of the earth towards Equator experiences relativily constant temperature climate year Temperatures 01 30 2014 Annual Mean temperature Temperature cycles 30 year average surface air temperature Air temperature data Daily mean