Transcript 17.2 Heating the Atmosphere
17.2 Heating the Atmosphere
Energy Transfer as Heat
Heat is the energy transferred from one object to another due to the difference in their temperatures Electromagnetic Waves 3 mechanisms of energy transfer as heat: Conduction Convection Radiation
Transfer of heat through matter by molecular activity Energy is transferred by the molecules colliding into each other Ex) a hot metal spoon that was left in a hot pan Metals are good conductors of heat Air is a poor conductor of heat
Much of the heat transfer in the atmosphere Transfer of heat by mass movement or circulation within a substance Takes place in fluids (ocean and air) Takes place in solids (Earth’s mantle)
Travels out in all directions from it source Unlike conduction & convection, which need material to travel through, radiant energy can travel through the vacuum of space.
Solar energy reaches Earth by radiation
4 Laws Governing Radiation
1. all objects, at any temperature, emit radiant energy 2. Hotter objects radiate more total energy per unit area than colder objects do 3. The hottest radiating bodies produce the shortest wavelengths of maximum radiation 4. Objects that are good absorbers of radiation are good emitters as well.
What Happens to Solar Radiation?
When radiation hits an object 3 different things could happen: Some energy is absorbed by the object Substances such as water & air are transparent to certain wavelengths of radiation Some radiation may bounce off the object without being absorbed or transmitted
Reflection, Scattering, & Absorption Reflection: occurs when light bounces off an object. The reflected radiation has the same intensity as the incident radiation.
Scattering: produces a larger number of weaker rays that travel in different directions. Disperses light forward & backwards Absorption: without the absorbing gases in the atmosphere, we would not be able to live on Earth due to the Greenhouse Effect
17.3 Temperature Controls
Why Temperatures Vary
Factors other than latitude that exert a strong influence on temperature include heating of land & water, altitude, geographic position, cloud cover, & ocean currents Land heats more quickly & to higher temps. than water. And land cools quicker than water and to a lower temp. Geographic Position Altitude Cloud Cover & Albedo
World Distribution of Temperature Isotherms are lines that connect points that have the same temperature.
Study global temperature patterns & the effects of the controlling factors of temperature