Earth’s Energy Budget of Solar

Energy

Purpose• To understand how Earth is heated from it

major source the Sun.– Reflection, absorption, and scattering of the Sun’s

electromagnetic spectrum energy

http://www.sci.uidaho.edu/scripter/geog100/lect/02-energy-seasons-atmosphere/02-pt-1-solar-energy.htm

Part 1• What kinds of natural

substances on Earth reflect solar energy? – Reflect: Snow, Water, Clouds

• Data– Clouds vs. No Clouds in full

greenhouse and dark soil.• 30 units are reflected by

clouds• Where do the other 70

units go?

Part 2• Albedo: the percentage of solar

energy reflected back by a surface

• Which of the materials here (black soil, white sand, water) do you think are reflecting more radiation, and which are absorbing more?– Reflects: Water and white sand– Absorbs: Black soil and water

absorbs more, but takes longer.• 50 absorbed by ground• 20 absorbed by atmosphere and

clouds

• Data– Temperature in soil and water

Part 2 Continue• What happens to the solar energy

while it is in the natural materials?– Short wavelengths (that don’t get

absorbed by the atmosphere) make atoms vibrate (kinetic energy), which warms the ground.

– The atoms release the energy as heat (infrared radiation - IR).

• What happens to the energy after it is re-emitted from the ground as infrared radiation?– 12 units (longest waves) go into space

Part 3• Where does the rest of infrared

radiation(IR) go? – Greenhouse gasses

• H2Ov, CO2, Methane, Nitrous Oxide, and O3

– 8 units• Data• Greenhouse effect (Scattering)

– Energy is released as IR and then is constantly absorbed and released by greenhouse gases = heat

– Good thing– Greenhouse enhancement: adding to much

CO2

• What happens when the sun goes down?

Part 4

• Which material (water or soil) will release heat the fastest (and slowest)?– Soil will release it fast– Water absorbs more heat but releases it slowly

• Data– Water temperature air temperature vs. Soil air

temperature– Water temperature vs. soil temperature

Mountain and Valley Breezes• Valley Breeze (Day)– Valleys heat faster than

mountains = Warm air from valleys moves upslope.

• Mountain Breeze (Night)– Mountains cool faster

than valleys = cool air descend from mountains to valleys

Land and Sea breezes

• Sea Breezes (Day)– Water towards the land– Land heats up quicker

than water• Land Breezes(Night) – Land towards the Water– Land cools quicker than

water