HEATING THE ATMOSPHERE
Earth and Sun 99.9% of Earth s heat comes from Sun But <.0000001% of energy given by Sun
The Solar System 3 rd Planet from Sun
Earth Movements Rotation on Axis Revolution around Sun
Rotation on Axis Rotation Direction Towards the East Counterclockwise viewed from N Pole
Revolution Around Sun 365¼ Days Counterclockwise Direction
Revolution Around Sun Orbit NOT circular Varies during year
Revolution Around Sun Perihelion Closest 91.5 mln. mi. Jan. 3 Aphelion Farthest 94.5 mln. mi. July 4 Effect on Seasons?
Plane of the Ecliptic Orbital Plane of Earth relative to Sun
Inclination of Axis Earth Rotates on Axis Connects Poles Inclined 23½ from Vertical Causes Seasons
Annual Seasons Solstices Equinoxes
Annual Seasons
Seasonal Changes Hrs. of Daylight Sun Angle
June Solstice June 21 North Axis Tilted towards Sun No. Hemisphere Summer Solstice 1 st Day of Summer Longest Hours of Daylight
December Solstice December 21 North Axis Tilted away from Sun No. Hemisphere Winter Solstice 1 st Day of Winter Shortest Hours of Daylight
Equinoxes N-S Axis Tilt Sideways to Sun No. Hemisphere March 21 = Vernal Equinox 1 st Day of Spring September 22 = Autumnal Equinox 1 st Day of Fall Hrs. of Daylight?
Equinoxes Daylight Equal Nights 12 hours Daylight Everywhere Circle of Illumination ½ in Sunlight ½in Darkness
Hours of Daylight June 21 At Equator? Daylight = Night Farther North? Longer Daylight Farther South? Shorter Daylight
Max/Min Daylight June 21 66½ N to 90 N Arctic Circle North Pole 24 hours Daylight 66½ S to 90 S Antarctic Circle South Pole 24 hours Dark
Greenland July, 10 pm
Hours of Daylight Dec. 21 At Equator? Daylight = Night Farther North? Shorter Daylight Farther South? Longer Daylight
Max/Min Daylight Dec. 21 66½ N to 90 N Arctic Circle North Pole 24 hours Dark 66½ S to 90 S Antarctic Circle South Pole 24 hours Daylight
So. Chile January, 10 pm
Latitude & Daylight June 21 Solstice North of Equator > 12 hours (Summer) South of Equator < 12 hours (Winter) December 21 Solstice North of Equator < 12 hours (Winter) South of Equator > 12 hours (Summer)
Land of the Midnight Sun 24-hour Daylight in High Latitudes Sun skirts Horizon and doesn t set
Sun Angle Affects Sunlight Amount Intensity Most Intense Sunlight? Sun Directly Overhead 90 Sun Angle Equinoxes Sun directly over Equator
Sun Angle June 21 Tilt? No. Hemisphere Sun directly over Tropic of Cancer Summer Solstice No. Hemisphere Winter Solstice So. Hemisphere
Sun Angle December 21 Tilt? So. Hemisphere Sun directly over Tropic of Capricorn Summer Solstice So. Hemisphere Winter Solstice No. Hemisphere
Latitude Sun Overhead June 21 Tropic of Cancer 23½ N December 21 Tropic of Capricorn 23½ S
Latitude Midnight Sun June 21 Arctic Circle & North 66½ N December 21 Antarctic Circle & South 66½ S
Noon Sun Angle
Sun Angle & Energy Angle varies Energy Earth s surface 90 Sun Angle (Overhead) = Most Energy Small Sun Angle = Less Energy (larger area)
Sun Angle & Atmosphere Low Angles Sun Rays Go thru more Atmosphere Sun rays depleted
Latitude & Temperature Average Monthly Temperature Low Latitudes Little variation High Latitudes Greater variation between Winter & Summer
Calculating Sun Angle Difference from where overhead
Analemma Used for calculating Sun Angle Latitude for Date Sun overhead (90 ) at Noon Locations between Tropic of Cancer Tropic of Capricorn
Energy & Temperature Energy = Capacity to do work Kinetic = Energy in motion Potential = Capability to do work Temperature How warm or cold
Heat Heat Transfer of Energy in or out of object How is something Heated? By absorbing Energy Molecular movement speeds up Heat = Lots of molecular motion
Heat Transfer Mechanisms Conduction Convection Radiation Transmission Absorption Redirection Reflection Scattering
Conduction Heat Energy transfers between Molecules without movement Solids
Convection Heat Energy moves Molecules Circular motion Fluids = Liquid or Gas
Radiation Heat Energy transfers without a substance Solar Radiation thru space to Earth Electromagnetic Radiation
Electromagnetic Radiation Travels at different wavelengths
Electromagnetic Spectrum Solar Radiation is mostly Ultraviolet (UV) Visible Light Sunburn Infrared
Laws of Radiation All objects emit radiant energy Hot objects radiate more energy than Cold objects Sun Hotter objects radiate more short wavelength energy Sun = Short wavelength radiation Earth = Long wavelength radiation Objects that are good absorbers are good emitters Blackbody
Transmission Energy passes through Transparent like glass Air = Good Transmission Ocean = Good Transmission Earth = Poor Transmission Closed Car More Energy Transmitted in then out
Absorption vs. Reflection Object Heats by Absorption of Energy Reflection Object Repels Energy
Absorption vs. Reflection Absorption or Reflection dependent on Albedo Reflectivity of object Radiation NOT absorbed
Albedo of Surfaces Light High Albedo Dark Low Albedo
Scattering Energy deflected & redirected by Aerosols & Gas molecules Clouds Haze Diffused Light Shade & Indoors
Scattering Blue light scatters (shorter wavelengths) Why sky is Blue at mid-day Sunset on Horizon scatters more Only Red & Orange light is left
Incoming Solar Radiation 70% Absorbed 50% by Land Sea 20% by Atmosphere Clouds
Incoming Solar Radiation 30% Reflected back to Space Clouds = 20% Land-Sea = 5% Backscattered by Atmosphere 5%
Heating the Atmosphere Solar Radiation is Short Wavelength Air = Poor Absorption Transparent to Solar Radiation Does not heat air Earth s surface = Good Absorption
Heating the Atmosphere Earth Radiation is Long Wavelength Thermal Infrared Absorbed by Greenhouse Gases H 2 O vapor Clouds CO 2 Heats from ground up
Heating the Atmosphere Greenhouse Gases Reradiate Energy back to Earth Trap Heat in Atmosphere Increased CO 2 by Humans Increases Global Temperatures
Earth s Heat Budget Incoming = Outgoing
Latitudinal Heat Balance 38 S 38 N
Latitude Differences Poles colder Low Sun Angle High Albedo ICE
Incoming Solar Radiation JUNE Northward Latitudinal shift
Incoming Solar Radiation DECEMBER Southward Latitudinal shift