Heating of the EarthHeating of the Earth• Energy Transfers

–Conduction: transfer of heat from one object to another through touch. •A spatula warms up after sitting in a hot pan.

•Metals are the best conductors of heat, whereas air is the worst conductor of heat.

Heating of the EarthHeating of the Earth• Energy Transfers

–Convection: transfer of heat from one place to another through circulation.•In the ocean, warm currents move heat from the equator to higher latitudes.

Heating of the EarthHeating of the Earth• Energy Transfers

–Radiation: radiant energy that is emitted by an object.

Heating of the EarthHeating of the Earth• The atmosphere is

heated by radiation.• There are 4 laws

regarding radiation.

1. All objects, at any temperature, emit radiant energy.

2. Hotter objects radiate more total energy per unit area than colder objects do.

Heating of the EarthHeating of the Earth• The atmosphere is heated by

radiation.• There are 4 laws regarding

radiation.

3. The hottest radiating bodies produce the shortest wavelengths with maximum radiation.

4. Objects that are good absorbers of radiation are also good emitters.

Heating of the EarthHeating of the Earth• Solar Radiation

– There are 3 different results when radiation strikes an object.

1. Some energy is absorbed by the object.

2. Substances such as water and air are transparent to certain wavelengths of radiation.

3. Some radiation may bounce off the object without being absorbed or transmitted.

Heating of the EarthHeating of the Earth• Solar Radiation

– Reflecting: light bounces off an object in 1 direction.

– Scattering: light bounces off an object in several directions; the total amount of energy is divided up into the various rays.

– Absorption: an object takes in the heat and energy received by radiation.

Solar RadiationSolar Radiation

Temperature DifferencesTemperature Differences• Land and Water

Differences– Land heats and cools more

quickly than water.– The temperature range is

greater for land than water.• The land heats up to a higher

temperature than water can and will cool lower than water can.

• In the Northern Hemisphere, there is 39% land; whereas the Southern Hemisphere has 19% land.

– What does this indicate?

Temperature DifferencesTemperature Differences• Geographic

Differences– In California, the

wind blows mainly from the water to the land and the temperatures stay relatively consistent.

– In New York, the wind blows mainly from the land and the temperatures change frequently.

Temperature Differences Temperature Differences (cont’d)(cont’d)

• Seattle, WA and Spokane, WA are a couple hundred miles away from each other, but because there is a mountain range between them, they have different climates.– Seattle is on the western side

of the mountains and receives winds from the ocean resulting in little temperature changes.

– Spokane is on the eastern side of the mountains where there is no wind from the ocean has bigger temperature changes.

Temperature DifferencesTemperature Differences

• Altitude Differences– Two cities in Ecuador,

Quito and Guayaquil, are close to each other, but have different average temperatures.

• Quito is high in the mountains and has a lower average temperature.

• Guavaquil is close to the sea level and has a higher average temperature.

Temperature DifferencesTemperature Differences• Cloud Cover and

Albedo– Albedo is the amount of

radiation that is reflected back to space.

• Clouds have a high albedo, leading to less solar radiation reaching Earth, causing lower temperatures during the day.

• At night, clouds trap heat in the atmosphere and keep the temperature higher.

World Distribution of World Distribution of TemperatureTemperature• Isotherms are lines that show

differences in temperature (similar to contour lines on a topographic map) on an isothermal map.– The temperatures on these

maps are taken at the same elevation in order to eliminate any differences in altitude.

– The higher latitudes have cooler average temperatures and have greater temperature changes.

– Latitudes close to the Equator have higher average temperatures and very little temperature changes.