Chapter 2

300,000

This is the speed of light in kilometers per second

September 22nd

When is the autumnal equinox?

terrestrial radiation

Are gases in the atmosphere more effective at abdsorbing solar radiation or terrestrial radiation?

cool

Because well developed low level clouds are effective at reflecting much incoming solar radiation (especially visible light), does cloud cover in the day tend to keep the surface warmer or cooler than it would be if there were clear skies?

59

Carbon dioxide and water vapor are especially important to the greenhouse effect on Earth. About how many degrees of temperature are thought to be due to the greenhouse effect on Earth?

Lower angle rays spread over a greater area & lower angle rays have to penetrate more atmosphere

Changes in the noon-time angle of the Sun above the horizon over the course of the seasons results in these two important factors regarding the incoming rays of the Sun. These two factors contribute greatly to the differences between the seasons.

enhance

Does volcanic ash in the atmoshpere (often found after a significant volcanic eruption) tend to enhance or reduce the effect of sunsets?

Poleward of 38 degrees N and 38 degrees S

In this latitudinal belt more heat is lost through longwave terrestrial radiation than is recieved from the Sun over the year.

Vernal Equinox, Autumnal equinox

On only these two days of the year the Sun's rays shine vertically upon the Equator and there are 12 hours of daylight and 12 hours of darkness everywhere on these two days. What are these two days called in the northern hemisphere?

Winter solstice

On or about December 21st, known as the first day of winter in the northern hemisphere, the Sun's rays shine vertically on the Tropic of Capricorn on this day, and points in the northern hemisphere recieve the least amount of sunlight in a 24-hour period on this day. On this day every point north of the Arctic circle experiences 24 hours of darkness and every point south of the Antarctic circle experiences 24 hours of daylight. What is this day called?

Summer solstice

On or about June 21st, known as the first day of summer in the northern hemisphere, the Sun's rays shine vertically on the Tropic of Cancer on this day, and points in the northern hemisphere recieve the greatest amount of sunlight in a 24-hour period on this day. On this day every point north of the Arctic circle experiences 24 hours of daylight and every point south of the Antarctic circle experiences 24 hours of darkness. What is this day called?

July 4th

On this date the Earth is at its aphelion in its orbit around the Sun. It is at its farthest point from the Sun on this date at about 94.5 million miles.

January 3rd

On this date the Earth is at perihelion in its orbit around the Sun. It is closesd to the Sun on this date at about 91.5 million miles.

Changes in the length of day

Ranging from less than 9 hours of daylight to nearly 16 hours of daylight over the course of a year for Mt. Pleasant, this is a critical change marking the different seasons on Earth.

warmer

Since water droplets in clouds are fairly effective at 'trapping' heat, does cloud cover at night tend to keep the surface warmer or cooler than it would be if there were clear skies?

infrared

The peak intensity of solar radiation falls in this portion of the electromagnetic spectrum.

visible

The peak intensity of terrestrial radiation falls in this portion of the electromagnetic spectrum.

insulators

These are poor conductors (i.e. plastic, foam, down, snow, etc.)

crepuscular

These bright often fan-shaped bands of light are seen when the Sun shines through a break in the clouds. They are visible due to scattering of light by haze, water droplets, or dust particles.

atmosphere

This absorbs about 20% of incoming solar radiation

land-sea surface

This absorbs about 50% of incoming solar radiation

23.5 degrees

This fundimental deviation of the Earth's rotational axis from vertical to the plane of the ecliptic is responsible for the seasons on Earth.

global warming

This generally refers to human contributions to the greenhouse effect.

blue skies

This happens in the daytime on Earth due to gases (esp. nitrogen) in the atmosphere more readily scattering the shorter wavelengths (blue and violet) of solar radiation.

red sunsets

This happens in the near sunrise or sunset because low angle sunlight has to travel through more atmosphere, most of the blues & violets get scattered out.

<10

This index refers to the minutes it takes the most sensitive skin types to burn when exposed to varying levels of ultraviolet radiation

temperature

This is a measure of the average kinetic energy of the atoms or molecules in a substance.

energy

This is the capacity to do work.

kinetic energy

This is the energy associated with an object by virtue of its motion (i.e. moving hammers, winds, moving molecules, etc.)

potential energy

This is the energy associated with an object with the potential to do work (i.e. suspended object, wood, gasoline, etc.)

Plane of the ecliptic

This is the name often used for the orbital plane of the Earth.

terrestrial radiation

This is the portion of the electromagnetic spectrum emitted by the Earth.

solar radiation

This is the portion of the electromagnetic spectrum emitted by the Sun.

electromagnetic spectrum

This is the spectrum of radiation ranging from very short to very long wavelengths

186,000

This is the speed of light in miles per second

heat

This is the transfer of energy into or out of an object beecause of temperature differences between that object and its surroundings. This transfer always flows from a region of higher temperature to one of lower temperature.

Between 38 degrees N and 38 degrees S

This latitudinal belt receieves more solar radiation than is lost to space over the year.

radiation

This mechanism of heat transfer does not require a medium of transport

convection

This mechanism of heat transfer involves the actual movement or circulation of a substance (i.e. air, water). The term often refers to mainly vertical movements of air

conduction

This mechanism of heat transfer involves the transmission of heat through electron and molecular collisions from one molecule to another

Earth's heat budget

This refers to the annual balance of incoming and out-going radiation on Earth.

diffused light

This results from light scattered by dust particles and gas molecules in atmosphere. It is the main reason why shadowns on Earth are not completely black, while shadows on an airless world like the Moon are essentially completely black.

solar day

This rotational period for Earth is based on the planet's rotation relative to the Sun and is 24 hours long

sidereal day

This rotational period for Earth is based on the planet's rotation relative to the stars and is only about 23 hours and 56 minutes long.

Analema

This simple device is used to calculate the angle of the noon Sun for any location on Earth and for any day of the year.

solar

This source of radiation accounts for more than 99% of the energy that heats the Earth's atmosphere

blackbody

This term refers to a perfect absorber or emitter of radiation

backscattered

This term refers to scattered light lost to space.

advection

This term refers to the horizontal component of convective flow.

revolution

This term refers to the process of the Earth moving around the Sun.

albedo

This term refers to the total reflectivity of a surface

thermals

This term refers to warm, less dense parcels of air that float upward (due to their greater buoyancy than the air around them).

March 20th

When is the vernal equinox?

scattering

With respect to the fate of incoming radiation, this consists of the dispersion of light in many directions, though more forward than backward.

reflection

With respect to the fate of incoming radiation, this is the process whereby light bounces back from an object at the same angle at which it encounters a surface with the same intensity