CHAPTER 2: HEATING AND THE EARTH'S ATMOSPHERE

Flashcards covering key vocabulary related to heating and Earth's atmosphere based on Dr. Bayron's lecture notes.

Sun's Diameter

109 times that of Earth.

Earths inside the Sun

About 1.31 million Earths could fit inside the Sun.

Sun-Earth Distance

About 93 million miles.

Time for Sunlight to Reach Earth

8 minutes and 20 seconds.

Sun's Corona Temperature

About 3.5 million degrees F.

Sun's Core Temperature

Over 27 million degrees F.

Solar Insolation (Solar Irradiance)

Energy per unit time per unit area.

Rotation

Spinning of Earth on its tilted axis (23.5-degree tilt).

Revolution

Movement of Earth around the Sun.

Perihelion

The point in Earth's orbit closest to the Sun (91.5 million miles).

Aphelion

The point in Earth's orbit farthest from the Sun (94.5 million miles).

Latitude

Imaginary lines on Earth which run east and west but measure a degree north or south from the Equator.

Longitude

Imaginary lines on Earth which run north and south but measure a degree east or west from the Prime Meridian.

Earth's Rotation Speed

360 degrees / 24 hours = 15 degrees per hour, which defines time zones.

Primary Cause of Earth's Seasons

Earth's 23.5-degree axial tilt, which changes the angle of the Sun's rays at Earth's surface.

Solstice

Occurs around June 21-22 (Summer Solstice) and December 21-22 (Winter Solstice), marking maximum/minimum daylight hours and when the sun is vertical at 23.5°N or 23.5°S latitude.

Equinox

Occurs around March 21-22 (Spring/Vernal Equinox) and September 22-23 (Fall/Autumnal Equinox), when Earth is not tilted toward or away from the sun, solar declination is 0°, and all locations on Earth have equal daylight hours.

Sun Angle (Solar Elevation Angle)

The angle between the surface and the sun's rays.

Zenith Angle (ZA)

The angle between the sun's rays and the vertical (line perpendicular to the surface); same as 90° - Sun Angle.

Solar Declination (Sub Solar Point)

The latitude at which the Sun's rays are perpendicular to Earth's surface (i.e., location receiving direct sunlight).

Summer Solstice (Northern Hemisphere)

NH tilted towards the sun, solar declination at 23.5°N, maximum daylight.

Winter Solstice (Northern Hemisphere)

NH tilted away from the sun, solar declination at 23.5°S, minimum daylight.

Spring/Vernal Equinox

Earth not tilted away or towards the sun, solar declination is 0°, equal daylight at every location.

Fall/Autumnal Equinox

Earth not tilted away or towards the sun, solar declination is 0°, equal daylight at every location.

Sidereal Day

The time it takes for Earth to rotate 360°, approximately 23 hours 56 minutes 4 seconds.

Solar Day

The time it takes for the sun to be overhead twice in a row, approximately 24 hours.

Circle of Illumination

At any given time, half of the Earth is illuminated by the Sun.

Temperature

The average kinetic energy of the atoms or molecules in a substance.

Heat (Thermal Energy)

Energy transferred into or out of an object because of temperature differences between that object and its surroundings.

Latent Heat

Heat released or absorbed due to phase changes.

Sensible Heat

Heat that we can feel and measure that does not result in a phase change.

Conduction

Heat transferred through collisions of molecules and electrons from one molecule to another.

Convection

Heat transferred via movement or circulation of a fluid substance due to changes in density.

Advection

Primarily describes the horizontal component of convective flow.

Radiation

The emission of energy as electromagnetic waves.

Wavelength

Describes the distance between the crest of one wave and the next.

Visible Light

Often referred to as 'white light,' describes the sensitivity of the human eye to a range of wavelengths.

Infrared Radiation

Cannot be seen by the human eye but is felt as heat.

Ultraviolet Radiation

Consists of wavelengths that may cause sunburns, on the opposite side of the visible spectrum from infrared.

Stefan-Boltzmann Law

States that the total amount of energy emitted by a body per unit area across all wavelengths per unit time is proportional to its temperature.

Wien's Displacement Law

Describes an inverse relationship between a body’s temperature and its peak (most common) emission wavelength; warmer temps emit shorter wavelengths.

Laws of Radiation

All objects continually radiate energy, hotter objects radiate more total energy (Stefan-Boltzmann Law), hotter objects radiate more shortwave radiation (Wien's Displacement Law), and good absorbers are also good emitters.

Transmission (Radiation)

The passing of energy through the atmosphere without interacting with gases or other particles.

Absorption (Radiation)

Light gets absorbed and reemitted at another lower wavelength.

Reflection (Radiation)

Light bounces back from an object at the same angle and intensity.

Scattering (Radiation)

Produces a large number of weaker rays traveling in different directions.

Albedo

The percent of light reflected from a surface due to its color, roughness, and incident ray angle. High albedo means mostly reflection, low albedo means mostly absorption.

Effect of Surface Roughness on Albedo

Smoother surfaces reflect more light, leading to higher albedo.

Effect of Cloud Cover on Radiation

More cloud cover blocks radiation from both leaving and entering the Earth system.

Effect of Sun Angle on Albedo

Decreased sun angle increases albedo, meaning more sunlight is reflected at sharp angles.

Why the Sky is Blue

Blue light is scattered most efficiently through our atmosphere.

Why Sunsets are Red

When the sun is setting, its light passes through a greater length of the atmosphere, filtering out shorter wavelengths and leaving red and orange behind.

Atmospheric Heating Gases

Ozone absorbs incoming shortwave UV radiation, while CO2 and H2O absorb outgoing longwave radiation from the Earth.

Greenhouse Gases

Gaseous molecules which absorb outgoing longwave radiation, most importantly CO2 and H2O.

Greenhouse Effect

Greenhouse gases absorb outgoing longwave radiation and re-emit it in all directions, trapping heat in our atmosphere and raising Earth's average temperature from 0°F to 59°F.

Annual Energy Budget

The tropics and subtropics have an energy surplus, while mid-latitudes and polar regions have an energy deficit, balanced by global wind systems, ocean currents, and storms.