4.7 - Solar Radiation and Earth's Seasons

Question 1

Solar intensity of insolation depends on what?

Answer 1

1. Angle - how directly rays strike earth’s surface
2. The amount of atmosphere sun’s rays pass through

Question 2

Does the equator have a higher or lower insolation than other latitudes?

Answer 2

higher because it is at a direct angle

Question 3

Explain the relationship between high latitudes and solar intensity

Answer 3

• at higher latitudes sunlight must pass through more atmosphere, losing most of its energy
• A given amount of solar energy is spread over a larger surface because of the angle

Question 4

What changes the angle of the sun’s rays?

Answer 4

• orbit of the earth
• tilt on the earth’s axis

Question 5

What is a result of the earth’s tilt and orbit?

Answer 5

varying isolation, length of day, and seasons

Question 6

T or F
The earth’s tilt changes during orbit?

Answer 6

False
The earth’s tilt stays the same during orbit

Question 7

What is the result of the earth’s tilt remaining the same during orbit?

Answer 7

Equinoxes and Solstices (seasons)

Question 8

Explain the earths equinoxes and solstices

Answer 8

• June Solstice: The northern hemisphere is maximally tilted towards the sun
  - Longest day in the N (summer)
  - Shortest day in the S (winter)
• December Solstice: The southern hemisphere is maximally tilted towards the sun
  - Shortest day in the N (winter)
  - Longest day in the S (summer)
• March Equinox: The north and south hemisphere are equally facing the sun
  - the Equator gets the most direct isolation
  - N & S hemispheres get 12 hours of sun
  - Spring in N/Fall in S
• September Equinox: The north and south hemisphere are equally facing the sun
  - The equator receives most direct isolation
  - N & S get 12 hours of sunlight
  - Fall in N/Spring in S

Question 9

The tilt of earth’s axis causes variation in

Answer 9

1. Seasons
2. Angle of Isolation - which changes intensity
3. Length of day

Question 10

What is Albedo?

Answer 10

the proportion of light that is reflected by a surface

Question 11

What is the relationship between surfaces and high/low albedo?

Answer 11

• Surfaces with higher albedo reflect more light and absorb less
  - absorb less heat
  - Ice/snow
• Surfaces with low albedo reflect less and absorb more
  - absorb more heat
  - water

Question 12

What is affected by albedo?

Answer 12

Surface temperature

Question 13

What happens when sunlight is absorbed by the surface?

Answer 13

• the surface gives of infrared radiation (heat)
  - areas with low albedo absorb more sunlight (heat)

Question 14

What is an urban heat island?

Answer 14

Urban areas are hotter than surrounding rural areas due to low albedo of blacktop

Question 15

Why are polar regions cooler?

Answer 15

They have a higher albedo so they do not absorb most of the heat