GEOG 131 Chapters 3 and 4 Concise Study Guide

Comprehensive question-and-answer flashcards based on GEOG 131 Chapters 3 and 4 Concise Study Guide, covering solar energy, Earth-Sun geometry, atmospheric composition/layers, radiation transfer, temperature controls, and unit conversions.

What holds Earth and the other planets in orbit around the Sun?

Gravity keeps Earth and the other planets in orbit around the Sun.

What is the definition of the habitable zone?

The orbital range where solar input may permit liquid surface water.

When is Earth at perihelion and aphelion, and does distance cause the seasons?

Earth is closest to the Sun (perihelion) in early January and farthest (aphelion) in early July; distance does not cause the seasons.

How is solar energy produced in the core of the Sun?

Fusion in the Sun's core converts hydrogen to helium and releases energy.

What is the solar constant and what is its value given in the study guide?

The average solar input at the top of the atmosphere on a perpendicular surface, which is about $1370\,\text{W/m}^2$.

What is insolation?

Incoming solar radiation received by Earth.

How do wavelength, frequency, and energy relate in electromagnetic radiation?

Shorter wavelengths have higher frequency and higher energy; longer wavelengths have lower frequency and lower energy.

How does the radiation emitted by the Sun compare to that emitted by Earth?

The hot Sun emits mainly shortwave radiation, while the cooler Earth emits mainly longwave thermal infrared radiation.

What range of wavelengths does visible light span, and what atmospheric gas absorbs most harmful ultraviolet radiation?

Visible light spans about $0.4\text{--}0.7\,\mu\text{m}$, and ozone absorbs most harmful ultraviolet radiation.

What is the difference between direct rays and oblique rays?

Direct rays concentrate energy over a smaller area and travel a shorter path through the atmosphere; oblique rays spread energy over a larger area and travel a longer path through the atmosphere.

What is the subsolar point?

The location where the Sun is directly overhead at solar noon.

What is solar declination?

The latitude of the subsolar point on a given date.

What is the circle of illumination?

The boundary between Earth's day and night sides.

Where is the subsolar point located on the March and September equinoxes, and what are the conditions in the Northern Hemisphere?

The subsolar point is at the Equator; the Northern Hemisphere experiences about $12\,\text{hours}$ of day and night, with spring beginning in March and autumn beginning in September.

Where is the subsolar point located on the June solstice, and what are the conditions in the Northern Hemisphere?

The subsolar point is at $23.5^\circ\,\text{N}$; the Northern Hemisphere experiences its highest Sun and longest day, marking the start of summer.

Where is the subsolar point located on the December solstice, and what are the conditions in the Northern Hemisphere?

The subsolar point is at $23.5^\circ\,\text{S}$; the Northern Hemisphere experiences its lowest Sun and shortest day, marking the start of winter.

What concept keeps Earth's axis pointed toward Polaris during its revolution around the Sun?

Axial parallelism.

What are the percentages of Nitrogen, Oxygen, and Argon in dry air?

Nitrogen accounts for $78.08\%$ of dry air, Oxygen accounts for $20.95\%$, and Argon accounts for $0.93\%$.

What is the atmospheric range and role of water vapor?

Water vapor varies from $0\text{--}4\%$ of the atmosphere; it is central to humidity, clouds, precipitation, latent heat, and warming.

What are aerosols and what is their role in the atmosphere?

Aerosols are particles or droplets that scatter or absorb energy and support cloud formation.

What is the temperature trend and key features of the troposphere?

Temperature decreases upward; it contains weather, water vapor, and most atmospheric mass.

What is the normal lapse rate in the troposphere?

An average temperature decline of about $6.4\text{--}6.5\,^\circ\text{C}$ per kilometer.

What is the temperature trend and key feature of the stratosphere?

Temperature increases upward because ozone absorbs ultraviolet radiation.

What is the temperature trend and key feature of the mesosphere?

Temperature decreases upward; it is the coldest layer near the top, where most meteors vaporize.

What is the temperature trend and key feature of the thermosphere?

Temperature increases upward as sparse gases absorb high-energy radiation; it overlaps much of the ionosphere.

What causes ozone depletion, and is it the same process as global warming?

Ozone depletion results mainly from chlorine and bromine released by ozone-depleting substances; it is not the same process as global warming.

How do Rayleigh scattering, Mie scattering, and nonselective scattering differ?

Rayleigh scattering involves air molecules scattering short wavelengths most strongly (e.g., blue sky); Mie scattering involves larger aerosols scattering light strongly forward (e.g., haze and glare); nonselective scattering involves cloud droplets scattering visible wavelengths nearly equally (e.g., white/gray clouds and fog).

What is refraction and what are two examples of its effects?

Refraction is light changing speed and direction through materials of different density; examples include mirages and apparent early sunrise.

How do radiation, conduction, convection, and advection differ as modes of heat transfer?

Radiation transfers energy via electromagnetic waves without a required medium; conduction transfers heat through direct contact; convection is vertical heat transfer by buoyant fluid movement; advection is horizontal transport by wind or currents.

What is latent heat?

Energy absorbed or released during a phase change (such as evaporation and condensation).

What is the difference between the natural greenhouse effect and the enhanced greenhouse effect?

The natural greenhouse effect warms Earth as greenhouse gases absorb and re-emit outgoing longwave radiation; the enhanced greenhouse effect is additional warming caused by human increases in greenhouse gases.

What is the difference between heat and temperature?

Heat is transferred energy; temperature measures average molecular kinetic energy.

What are daily lag and seasonal lag?

Daily lag is when the minimum temperature occurs shortly after sunrise and the maximum in midafternoon; seasonal lag is when the warmest and coldest periods occur weeks after the solstices because Earth stores heat.

What is a temperature inversion?

A condition in which temperature increases with height through a layer.

What is albedo?

The percentage of incoming solar radiation reflected by a surface.

What is an isotherm?

A line connecting places of equal temperature.

What are the six geographic temperature controls listed in the study guide?

Latitude, land and water, ocean currents, elevation, landforms, and human activity.

How do clouds affect diurnal temperature range?

Clouds generally reduce the diurnal range by cooling days and warming nights.

Why are isotherms more regular and east-west south of about $40^\circ\,\text{S}$?

Ocean dominance south of about $40^\circ\,\text{S}$ makes isotherms more regular and east-west than in the Northern Hemisphere.

What is the formula for converting Fahrenheit to Celsius?

$$(\text{degrees F} - 32) \times \frac{5}{9} = \text{degrees C}$$

What is the formula for converting Celsius to Fahrenheit?

$$(\text{degrees C} \times 1.8) + 32 = \text{degrees F}$$

What is the formula for converting Celsius to Kelvin?

$$\text{degrees C} + 273.15 = \text{K}$$

What is absolute zero?

The lowest possible thermodynamic temperature: $0\,\text{K}$ or $-273.15\,^\circ\text{C}$.

What is counterradiation?

Longwave energy emitted downward by the atmosphere.

What is specific heat?

Energy required to raise a unit mass by one degree.

What is the distinction between weather and climate?

Weather refers to atmospheric conditions at a specific time and place; climate refers to long-term statistics of weather, commonly based on $30\,\text{years}$.