Insolation. Objective TSWBAT: Explain the factors affecting insolation Explain the relationship...
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Transcript of Insolation. Objective TSWBAT: Explain the factors affecting insolation Explain the relationship...
Insolation
Objective TSWBAT: Explain the factors affecting insolation Explain the relationship between
temperature and insolation Describe evidence for Earth’s radiative
balance Define insolation, radiative balance Describe the four ways the atmosphere
is heated.
What could cause us to have different amounts of sunlight/insolation?
1. Angle 90o (direct rays) most intense insolation < 90o (less direct rays) least intense
insolation
Angle and Temperature 90o = higher temperature low angles = lower temperatures
2. Earth’s Shape If the Earth was flat, the angles would
all be 90o (high temperatures) The Earth is curved, so we get angles
from 0o to 90o (range of temperatures)
3. LatitudeFall/Spring – Equinox (March 21st and Sept
23rd) Perpendicular (90°) at the Equator (0°) Angle of incidence decreases as latitude
increases (lowest at the North Pole (90°N) and South Pole (90°S))
12 hours of daylight everywhere Altitude of noon sun: 47° Not tilted toward/away from sun Sunrise/set - E W
Fall/spring
Summer Solstice (June 21st)Perpendicular (90°) at the tropic of cancer (23
½ °N) 12 hours of daylight at equator (0°) 15 hours of daylight 43°N (Cambridge) 24 hours of daylight 90°N 9 hours of daylight at 40°S 0 hours of daylight at 90°S Altitude of noon sun: 70.5° Tilted toward the sun Sunrise/set - NE NW
Summer Solstice
Winter Solstice Dec 21st
Perpendicular (90°) at the tropic of Capricorn (23 ½ °S)
12 hours of daylight at equator (0°) 9 hours of daylight 43°N (Cambridge) 0hours of daylight 90°N 15 hours of daylight at 40°S 24 hours of daylight at 90°S Altitude of noon sun: 23 ½ ° Tilted away from the sun Sunrise/set - SE SW
Winter Solstice
4. Seasons Changes angles for latitudes NY: Summer 70o, Fall/Spring 47o, Winter
23 ½ o
5. Time of Day Sunrise and sunset have low angles
(lower temperatures) Noon has the highest angle We (NY) never get a 90o angle at noon
So, if you have a greater angle of insolation, what happens to intensity and temperature? Intensity will increase and temperature
will increase
6. Tilt of Axis If there was no tilt, there would be no
change in the seasons. The angles would stay the same, similar
to Fall/Spring.
7. Parallelism of Axis Helps to change the angles for the
latitudes It makes the axis tilt toward the sun or
away from the sun as it revolves around the sun
8. Revolution Same as Parallelism of Axis and Seasons Changes the angles for the latitudes
9. Rotation Causes the angles to change during the
day Refer to Time of Day
Duration of Insolation Means number of daylight hours If the angle of insolation is low, there is
a small duration of insolation (low temperatures)
Creates unequal distribution of heatWhy does this happen?Tilted axis of rotation – greater amounts
of insolation in the summer (northern hemisphere), less during the winter
Duration of insolation NY: Winter: 23 ½ o, 8 hours of daylight,
low temperatures, Dec 21st
Summer: 70o, 15 hours of daylight, high temperatures, high angle, high intensity
Fall/Spring - 47o 12 hours of daylight.
Radiative balance A condition in which a body gives off as much
heat as it receives. Insolation from Sun = infrared energy from
Earth
http://www.ieagreen.org.uk/tecres/tecim2.jpg
Evidence for radiative balance: daily
http://apollo.lsc.vsc.edu/classes/met130/notes/chapter3/graphics/t_diurnal3.free.gif
Evidence of Radiative balance 1. Hottest and coolest times of day
(4pm (maximum radiative energy) and 6am(minimum radiative energy))
2. Hottest and coolest times of year (July/Aug (maximum radiative energy) and Jan/Feb (minimum radiative energy))
Is Earth really in radiative balance? Radiative balance means insolation =
re-radiation. Over long periods of time, Earth is in
radiative balance. Temperatures taken year to year vary
though (short periods).
Heating the atmosphere1. Direct absorption of radiation from the
sun2. Re-radiation of long-wave radiation
from earth’s surface3. Conduction4. Latent heat of condensation
1. Direct absorption of radiation from the sun Gases absorb long-wave and short-wave
radiation Transferred into heat energy
2. Re-radiation of long-wave radiation from earth’s surface Short wave radiation is absorbed by
earth Reradiates long wave infrared radiation
also called terrestrial radiation Gases in the atmosphere absorb this
infrared reradiation and are heated
3. Conduction Transfer of heat by direct molecular
contact Not all heat energy in rocks reradiate
back Some is through direct contact of the
hot rocks with the atmosphere
4. Latent heat of condensation
Water vapor condenses to liquid water - Release (condensation) of latent heat
gain (evaporation) of latent heat – cooling effect
Ex) body sweat evaporates and draws heat away from your body. The heat is stored in water vapor and rises in the atmosphere.
When it condenses, heat is releases as latent heat.
Clouds form and massive storm systems Body sweat may help form a cloud!!