Thermal Response of Climate System Weather Update Finish Seasons and Solar Elevation at Noon Heat Transfer Processes Latent Heat Transfer Heating Imbalances For Next Classs: Read Christopherson Ch. 4 (pp ) available on AsUlearn

© AMS2 Chapter 4: Driving Question What are the causes and consequences of heat transfer within Earth’s climate system? What are the causes and consequences of heat transfer within Earth’s climate system?

© AMS3 Heat Transfer Processes Radiation Radiation Both a form of energy and a means of energy transferBoth a form of energy and a means of energy transfer Radiational heating: object absorbs radiation at a greater rate than it emits radiationRadiational heating: object absorbs radiation at a greater rate than it emits radiation Internal energy increases, temperature rises Internal energy increases, temperature rises Radiational cooling: object emits radiation at a greater rate than it absorbs radiationRadiational cooling: object emits radiation at a greater rate than it absorbs radiation Internal energy decreases, temperature drops Internal energy decreases, temperature drops

© AMS4 Heat Transfer Processes Conduction and Convection Conduction and Convection Conduction: the transfer of kinetic energy of atoms or molecules via collisions between neighboring atoms or moleculesConduction: the transfer of kinetic energy of atoms or molecules via collisions between neighboring atoms or molecules Heat Conductivity: the ratio of the rate of heat transport across an area to the temperature gradientHeat Conductivity: the ratio of the rate of heat transport across an area to the temperature gradient Substances with a higher heat conductivity have greater rates of heat transport Substances with a higher heat conductivity have greater rates of heat transport Solids are better conductors than liquids, liquids are better conductors than gasesSolids are better conductors than liquids, liquids are better conductors than gases

© AMS5 Heat Transfer Processes Conduction and Convection Conduction and Convection Convection: the vertical transport of heat within a fluid via motions of the fluid itselfConvection: the vertical transport of heat within a fluid via motions of the fluid itself Generally only occurs in liquids or gases (fluids) Generally only occurs in liquids or gases (fluids) Convection in the atmosphere consequence of differences in air density Convection in the atmosphere consequence of differences in air density Advection is the horizontal transport of heat Advection is the horizontal transport of heat Sensible Heating: combination of conduction and convectionSensible Heating: combination of conduction and convection

© AMS6 Convection currents transport heat conducted from Earth’s surface into the troposphere A fresh layer of snow is a good heat insulator

© AMS7 Heat Transfer Processes Phase Changes of Water Phase Changes of Water Water occurs naturally in all three phases (solid, liquid, gas)Water occurs naturally in all three phases (solid, liquid, gas) Depending on phase changes, either absorbs or releases heat to or from environmentDepending on phase changes, either absorbs or releases heat to or from environment Latent heat: quantity of heat involved in phase changes of waterLatent heat: quantity of heat involved in phase changes of water Latent heating: the transport of heat from one location to another as a consequence of changes in the phase of waterLatent heating: the transport of heat from one location to another as a consequence of changes in the phase of water

© AMS8 Heat Imbalance: Atmosphere vs. Earth’s Surface Latent Heating Latent Heating Latent heat of fusion: amount of heat required to convert a solid at its melting point to a liquid without a change in temperatureLatent heat of fusion: amount of heat required to convert a solid at its melting point to a liquid without a change in temperature Latent heat of vaporization: amount of heat required to convert a liquid to a gas without a change in temperatureLatent heat of vaporization: amount of heat required to convert a liquid to a gas without a change in temperature

© AMS9 Heat Transfer Processes Phase Changes of Water Phase Changes of Water Heat absorbed from environment during changes to higher energy states melting, evaporation, sublimation Heat released to environment during changes to lower energy states freezing, condensation, deposition

© AMS11 Thermal Response and Specific Heat Specific Heat: amount of heat that will raise the temperature of 1 gram of a substance by 1 Celsius degree Specific Heat: amount of heat that will raise the temperature of 1 gram of a substance by 1 Celsius degree Measured relative to liquid waterMeasured relative to liquid water Water has the greatest specific heat of any naturally occurring substance Water has the greatest specific heat of any naturally occurring substance Variation in specific heat from one substance to another implies that different materials have different capacities for storing internal energyVariation in specific heat from one substance to another implies that different materials have different capacities for storing internal energy

© AMS12

© AMS13 Thermal Response and Specific Heat Maritime and Continental Climates Maritime and Continental Climates Maritime climates: immediately downwind of the ocean, and experience much less contrast between average winter and summer temperatureMaritime climates: immediately downwind of the ocean, and experience much less contrast between average winter and summer temperature Continental Climates: well inland, experience a much greater contrast between winter and summer temperatureContinental Climates: well inland, experience a much greater contrast between winter and summer temperature

© AMS14 Heat Imbalance: Atmosphere vs. Earth’s Surface Sensible Heating Sensible Heating The Bowen Ratio compares how heat at the Earth’s surface is divided between sensible heating and latent heatingThe Bowen Ratio compares how heat at the Earth’s surface is divided between sensible heating and latent heating Varies from one place to another Varies from one place to another Depends on amount of surface moisture Depends on amount of surface moisture Surface energy budget through the course of a year