17.2 Heating the Atmosphere

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

Energy Transfer as Heat

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

Conduction

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)

Convection

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

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.

4 Laws Governing 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

What Happens to Solar Radiation?

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

Reflection, Scattering, & Absorption

17.3 Temperature Controls

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

Why Temperatures Vary

Isotherms are lines that connect points that have the same temperature.

Study global temperature patterns & the effects of the controlling factors of temperature

World Distribution of Temperature