Chapter 2 -- Notes Flashcards
Define Perihelion
When the earth is closest to the sun, around January 3
Define Temperature
The measure of the average kinetic energy of the atoms, or molecules, in a substance. (Note: temperature is not a measure of the total kinetic energy of the particles within a substance.)
Define Aphelion
When the earth is farthest away from the sun, around July 6.
Define Plane of the ecliptic.
The plane the Earth orbits around the sun.
Define Inclination of the axis
It means that the earth tilts at a 23 1/2° angle.
Define Tropic of Cancer.
A line of latitude 23 1/2° (equal to the axis tilt) north of the equator, it is here that on June 21 or 22 the suns vertical rays strike.
Where do the vertical rays from the sun strike during the autumn and spring equinoxes.
The equator
Define Tropic of Capricorn
A line of latitude 23 1/2° (equal to the axis tilt) south of the equator, it is here that on December 21 or 22 the suns vertical rays strike.
Define Circle of illumination
The boundary separating the dark half of the earth from the lighted half.
When is the longest day of the year in the Northern Hemisphere? When is the shortest? (Opposite for Southern Hemisphere)
Summer solstice. Winter solstice.
True or false: The farther north a location is from the equator, the longer the period of daylight until the Arctic Circle is reached, where the length of daylight becomes 24 hours long. (opposite for the Southern Hemisphere)
True
During an equinox the length of daylight is _____ everywhere on earth because the circle of illumination passes directly through the poles, thus dividing the latitudes in half.
12 hours
Name the three ways the flow of energy can occur, and define them.
Conduction, the transfer of heat through electron and molecular collisions from one molecule to another.
Convection, heat transfer that involves the actual movement or circulation of a substance
Radiation, the only mechanism of heat transfer that travels thru the vacuum of space
Define thermals.
Parcels of rising air due to convection.
What is the difference to convection and advection?
Convection, the part of the atmospheric circulation that involves upward and downward.
Advection the horizontal component of convective flow, more commonly known as wind.
List the waves in shortest wavelength to longest.
Gamma rays, x-rays, ultraviolet (responsible for sunburn), visible, infrared (heat), radio.
Surfaces that are good absorbers of all wavelengths of visible light appear _____ in color, whereas ______ colored surfaces have much lower absorptivity.
Black, Light
Name the laws of radiation
- All objects continually emit radiant energy over a range of wavelengths.
- Hotter objects radiate more total energy per unit area than do colder objects.
- Hotter objects radiate more energy in the form of short wavelength radiation than do cooler objects.
- Objects that are good absorbers of radiation are good emitters.
Go to page 49! (while you’re there look at figure 2–13)
The fraction of radiation that is reflected by an object.
Albedo
What is the earth’s albedo?
30% or 0.3
How much of solar radiation absorbed at the earth’s surface is scattered light?
Over one half.
What does it mean if there’s a red sunset
That there are numerous small particles in the atmosphere.
What does it mean when there’s a white sky?
That there are numerous large particles in the sky.
The bluer the sky the ______ the air.
Cleaner
