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

Conduction

    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

Convection

    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)

Radiation

  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