2Objective TSWBAT: Explain the factors affecting insolation Explain the relationship between temperature and insolationDescribe evidence for Earth’s radiative balanceDefine insolation, radiative balanceDescribe the four ways the atmosphere is heated.
3What could cause us to have different amounts of sunlight/insolation?
41. Angle 90o (direct rays) most intense insolation < 90o (less direct rays) least intense insolation
103. Latitude Fall/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 everywhereAltitude of noon sun: 47°Not tilted toward/away from sunSunrise/set - E W
12Summer 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°N9 hours of daylight at 40°S0 hours of daylight at 90°SAltitude of noon sun: 70.5°Tilted toward the sunSunrise/set - NE NW
14Winter Solstice Dec 21stPerpendicular (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°N15 hours of daylight at 40°S24 hours of daylight at 90°SAltitude of noon sun: 23 ½ °Tilted away from the sunSunrise/set - SE SW
28Duration of Insolation Means number of daylight hoursIf 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
29Duration of insolation NY: Winter: 23 ½ o, 8 hours of daylight, low temperatures, Dec 21stSummer: 70o, 15 hours of daylight, high temperatures, high angle, high intensityFall/Spring - 47o hours of daylight.
30Radiative balanceA condition in which a body gives off as much heat as it receives.Insolation from Sun = infrared energy from Earth
34Evidence 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))
35Is 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).
36Heating the atmosphere Direct absorption of radiation from the sunRe-radiation of long-wave radiation from earth’s surfaceConductionLatent heat of condensation
371. Direct absorption of radiation from the sun Gases absorb long-wave and short-wave radiationTransferred into heat energy
382. Re-radiation of long-wave radiation from earth’s surface Short wave radiation is absorbed by earthReradiates long wave infrared radiation also called terrestrial radiationGases in the atmosphere absorb this infrared reradiation and are heated
403. Conduction Transfer of heat by direct molecular contact Not all heat energy in rocks reradiate backSome is through direct contact of the hot rocks with the atmosphere
414. Latent heat of condensation Water vapor condenses to liquid water - Release (condensation) of latent heatgain (evaporation) of latent heat – cooling effect
42Ex) body sweat evaporates and draws heat away from your body 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 systemsBody sweat may help form a cloud!!