Energy Balance & the Greenhouse Effect

Question 1

describe inverse square law

Answer 1

-total flux of energy transferred from one object (the sun) to another (the Earth) varies by 1/d^2

Question 2

why does solar flux vary with angle of earth

Answer 2

• more oblique angle gives a greater area over which the energy is absorbed, so less energy per unit area
• why the poles receive less energy than the equator

Question 3

define albedo

Answer 3

• ratio of reflected to incident radiation

- measure of reflectivity

Question 4

net solar radiation

Answer 4

incoming minus reflected radiation

Question 5

describe the net solar flux distribution

Answer 5

• higher at the equator/tropics/subtropics
• poles receive less overall
• varies depending on season & hemisphere

Question 6

describe the outgoing terrestrial flux distribution

Answer 6

• largest over the subtropics and deserts
• smallest over the poles in wintertime & deep tropics
• never zero
• seasonal variation follows the seasonal temperature
• more uniformly distributed than net solar fluxes

Question 7

what are the main components of earth’s atmosphere

Answer 7

nitrogen, oxygen, argon, water vapor, carbon dioxide

Question 8

which gases in the atmosphere interact with radiation

Answer 8

water vapor & carbon dioxide

Question 9

define greenhouse gas

Answer 9

gas that absorbs significantly the terrestrial radiation (infrared) emitted by the earth and its atmosphere

Question 10

criteria for a gas to interact with radiation

Answer 10

3 molecules

Question 11

define absorptivity

Answer 11

fraction of radiation that can be absorbed at that wavelength

Question 12

which type of radiation is mostly absorbed in the atmospehre

Answer 12

terrestrial

Question 13

describe greenhouse effect

Answer 13

energy absorbed by the surface is re-emitted as terrestrial radiation –> can’t make it’s way directly to space bc its absorbed by the atmosphere –> heats the surface