Energy Balance in the Atmosphere

Weather State of the atmosphere at any given time and place Components –Temp, wind, humidity, cloudiness, etc… Dynamic

Climate Characteristic weather of a region Temp and precipitation –Yearly, decade ave.

E.B. in the Atm Surface events driven by solar heating Weather and climate affected by complex variables –Ex. Solar radiation distribution Buffalo vs. McKinney

Of Waves and Packets We receive 1/2,000,000,000 th of Sun’s total output –Light behaves as both a packet of energy/particle (photon) and as a wave –Speed of light in a vacuum 3x10 8 m/sec

273 K = 0°C

Seeing things differently… The sun

It’s Such a Good Vibration Photons transmit energy causing: –Vibration of molecules (increased temperature) –Chemical/physical reactions in our skin

Such a Sweet Excitation Excitations of electrons –Subsequent release of energy

Emission of Radiation Everything omits radiation that is above -273ºC As Temp ↑ = Energy ↑ = Wavelength ↓

Absorption Sun (~6000ºC) emits high energy Earth absorbs it and then reemits it… but its temperature is lower –Emits low energy, long wavelength, invisible, infrared heat radiation

153 is energy released from Earth Of total energy released, 96 is trapped Clouds give off heat (internal plus re-emitted sunlight) 45 (new stuff) +19=64 Amount Earth loses to space is = 57

Colder on cloudy days Warmer on cloudy nights Albedo

Scattering Amount of scattering inversely proportional to wavelength of light –Blue scatters the most, so sky is blue Tank vs. me

Temperature, Heat, Conduction T: proportional to average speed of atoms Heat: Average energy * # of atoms Conduction: transport of heat by direct collisions

Convection Gases too mobile to be in contact –Radiant energy (waves) interact with gas molecules causing them to vibrate faster –Occupy greater volume, less density

Latent Heat Energy released or absorbed when a substance changes state Sweating keeps you cool Melting snow can cool the Earth

Heat Storage Specific Heat: Amount of energy needed to raise the T of 1 gram of water by 1ºC –Rocks = low specific heat –Water = high specific heat –Lakes in the summer time vs. winter time –Inlands vs. coast lines

Our Spherical Earth Earth = sphere Unequal distribution of sun’s rays

Seasons In addition to being spherical, the earth’s axis is tilted 23.5 degrees from vertical If not for tilt, there would be no seasons. Fall equinox Sept. 21st Summer Solstice June 21st Spring equinox March 21st Winter solstice Dec. 21st