InSolAtion – INcoming SOLar radiATION,
electromagnetic energy from the Sun, sunlight
Angle of Insolation – the angle at which the
sun’s energy reaches the Earth.
 When insolation is perpendicular to a
surface its intensity is maximum (striking
the surface at 90˚ angle) IT WILL
NEVER BE 90˚ OVER N.Y.S.
 Therefore: higher angle of insolation =
higher intensity = higher temperature (it is
warmer)
Time of Day – angle of insolation is the
same as the altitude of the sun.
 Sun’s altitude varies from 0˚ at sunrise
(East), increase all day to maximum at
apparent solar noon (South)(when the
sun is highest in the sky), then decrease
back to 0˚ again at sunset (West).
Duration – the length of time that insolation
is received each day (# hours the sun is
visible)
 Duration varies with latitude and the
seasons (length of daylight changes)
Seasons – 4 divisions of the year
characterized by different types of weather
conditions – major difference in seasons is
the temperature
 Causes:
o tilt of the Earth (23.5˚)
o parallelism of axis
o revolution of the Earth around the
Sun
****From June 21st until December 21st
the days are continuously getting shorter!
****From December 21st until June 21st
the days are continuously getting longer!
June 21st – first day of Summer (solstice)
 the Sun is perpendicular (90˚) at
23.5˚ North (Tropic of Cancer)
 longest day of the year
 16 hours of daylight, 8 hours of
darkness
 Sun will rise North of East, move
across the Southern sky, and set
North of West
 Northern Hemisphere tilted
toward the Sun
September 23rd – first day of fall/ autumn,
 (equinox)
 the Sun is perpendicular at 0˚
(Equator)
 12 hours of daylight and
darkness
 Sun will rise due East, move
across the Southern sky, and
set due West
December 21st – first day of Winter
(solstice)
 Sun is perpendicular at 23.5˚
South, (Tropic of Capricorn)
 Shortest day of the year
 8 hours of daylight, 16 hours
of darkness
 Sun will rise South of East,
move across the Southern sky,
and sets South of West
 Northern Hemisphere tilted
away from the Sun
March 21st – first day of Spring, (Vernal
Equinox)
 Sun is perpendicular to 0˚
(Equator)
 12 hours of daylight and
darkness
 Sun will rise due East, move
across the Southern sky, and
set due West