GEOG 1114 1st Edition Lecture 8 Outline of Last Lecture Atmospheric Composition based on gas distribution Human Induced Atmospheric change Weather and Climate Solar energy Insolation and temperature Electromagnetic Radiation EMR Electromagnetic Spectrum Outline of Current Lecture Solar Energy Insolation and Temperature continued Review of last lecture Processes of heating and cooling Spatial and Seasonal Variations in the Heat Budget Latitudinal Differences Current Lecture Review Sun Major source of energy for planet EMR spectrum 50 visible Balance between incoming shortwave insolation and outgoing longwave Some shortwave radiation reflected by atmosphere or surface Albedo the reflectivity of an object These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Basic Processes of Heating and Cooling Radiation processes by which heat is emitted by a body Warmer objects radiate more effectively hotter Warmer objects emit shorter wavelengths Sun ultimate hot body How Radiation Energy Interacts with an Object Absorption Body absorbs radiation Good radiator good absorber water sand Reflection Objects repel EMR reflect back Size material condition portion of spectrum play a role Good absorbers reflect little Snow on a warm day reflect a lot of energy Scattering Deflection of light waves by molecules and particles dust water Wavelength dependent Blue portion most scattered hence blue sky Sun sets dust Electromagnetic radiation EMR travels a longer distance reduced anglemore scattering of orange and red Transmission Electromagnetic waves pass completely through a medium Water good transmitter Atmosphere Transmits shortwave radiation well Transmission of energy and the greenhouse effect Greenhouse Effect Some atmospheric gases transmit shortwave radiation but not earth s longwave radiation Earth radiation held in by the atmosphere Atmospheric blanket Same effect in happens in cars How Energy is moved Conduction Movement of heat from one molecule to another Results from molecular collision Air is a poor conductor metal is good Allows heat to be transferred from one abject to another Convection Heat transfer by vertical circulation Molecules move in tandem Convection cell Advection Horizontal transfer of heat In the atmosphere wind may transfer warm or cool air horizontally Adiabatic Cooling Warming vertical changes in temperature Adiabatic Cooling Air rises and expands due to pressure changes molecular collisions decrease so temperature decreases Heat is dispersed air pressure decreases This rate can be accelerated with storm activity Adiabatic Warming Air sinks descends and compresses collisions increase so temperatures increase Increased pressure Changes in the storage and release of energy Evaporation Liquid water is converted to a gaseous water vapor Rates depend on temp Location pressure Cooling process energy is stored Condensation Water vapor changes to liquid Warming process Energy is released sensible heat latent heat Latent Heat Heat is released or absorbed during a phase change Latent since heat is not felt Most common phase changes Evaporation and Condensation The global heat budget is being interrupted by human activity Spatial and Seasonal Variations in the Heat Budget The Heat Budget of the earth is a broad generalization on heat transfer and movement through the atmosphere There are considerable imbalances both vertically through the atmosphere and horizontally over the earth s surface It s these differences that cause weather and climate variations Latitudinal Differences Angle of incidence latitude angle at which rays strike the earth Yearly poles receive fewer amounts Variable heating sets up unstable conditions Most of the evaporation happens at the equator Day Length latitude and tilt tied to seasons and latitude we tilt longer days more insolation evaporation absorption etc Atmospheric Obstruction clouds water vapor gas dust reduce intensity Migration of the Sun The direct rays of the sun shift northward and southward across the equator during the course of the year This belt of maximum energy swings through the tropics 213 5 N to 23 5 S Within this tropical belt there is an energy surplus In latitudes N S of tropics there is a deficit increasing pole ward