1. Aim: How can we explain insolation?

2. What’s different?
Sun’s Rays

3. Insolation INcoming SOLar radiATION
The sun’s energy that reaches Earth

4. Rays of light from the Sun that hit Earth are parallel
NOTE: NOT TO SCALE!!!!
Rays of light from the Sun that hit Earth are parallel

5. Factors Affecting the INTENSITY of insolation
Wavelength
Angle
Duration

6. 1. Wavelength
Infrared
Visible
Ultraviolet

7. Which wavelength is most intense?
Intensity of Insolation
VISIBLE
INFRARED UV
Visible
7% is UV
44% is visible
48% is infrared
Increasing Wavelength

8. 2. Angle The angle at which radiation strikes the Earth’s surface
The larger the angle, the higher the intensity

9. Rays less concentrated, more spread out Rays very concentrated
Flashlight Example
90o
30o
Rays less concentrated, more spread out
LOW intensity
Rays very concentrated
HIGH intensity

10. Angle affected by three factors:
a) Time of Day
b) Latitude (shape of Earth)
c) Season

11. a) Time of Day
The sun is the highest at NOON  rays most direct, angle of insolation is the highest
Sun’s rays most spread out at SUNRISE and SUNSET

12. Less concentrated, LOW intensity More concentrated, HIGHEST intensity
Sun at noon
Sun at sunrise E W
Less concentrated, LOW intensity
More concentrated, HIGHEST intensity

13. b) Latitude (shape of Earth)
Because of Earth’s shape, rays hit different latitudes at different angles
Hitting at 30o
8oC
Hitting at 90o
27oC

14. c) Season
The path of the sun in our sky changes during the year, resulting in changes in the angle of insolation

15. SUN’s rays at NOON for NYC
December 21st
March 21st and
Sept. 23rd
June 21st
Winter
Summer
Spring and Fall
48o
71.5o
24.5o
Low angle of insolation
Low intensity
Average angle of insolation
Average intensity
High angle of insolation
Highest intensity

16. 3. Duration
The length of time (sunrise to sunset) the sun is in the sky
For NYS:
Longest on June 21st
Shortest of December 21st
Long duration = HIGH intensity
As angle , temperature
As duration , temperature

18. The length of time that daylight is received at a location during one day is called the location’s
Angle of insolation
Intensity of insolation
Duration of insolation
Eccentricity of insolation

19. The diagram below represents a portion of Earth’s surface that is receiving insolation. Positions A, B, C, and D are located on Earth’s surface. At which position would the intensity of insolation be greatest? A B C D

20. As the altitude of the Sun increases, the length of the shadow cast by a vertical pole will
Decrease
Increase
Remain the same

21. The coldest climates on Earth are found at the polar regions because the polar regions
Absorb the most insolation
Are usually farthest from the Sun
Receive the shortest duration of insolation
Receive the lowest angle of insolation

22. What happens to the angle of insolation on June 21st between solar noon and 6 p.m. in New York State?
It decreases steadily
In increases steadily
It remains the same
If first increases and then decreases

23. In which diagram does the incoming solar radiation reaching the Earth’s surface have the greatest intensity?