eTextbook: Essentials of Meteorology - Chapter 1: Earth’s Atmosphere

Practice flashcards covering key concepts from Chapter 1 of Essentials of Meteorology, including atmosphere composition, structure, processes, measurement methods, and the relationship between weather, climate, and atmospheric phenomena.

What is the primary energy source for Earth\'s atmosphere?

The Sun’s energy drives the atmosphere and weather.

Define weather.

The state of the atmosphere at a particular time and place, described by the weather elements.

List the seven weather elements.

Air temperature, air pressure, humidity, clouds, precipitation, visibility, and wind.

Define climate.

The accumulation of daily and seasonal weather events, including extremes, over a long period.

What is meteorology and where does the term originate?

The study of the atmosphere and its phenomena; the word comes from Aristotle\'s Meteorologica.

What is the composition of Earth\'s atmosphere at the surface?

Mostly nitrogen and oxygen, with smaller amounts of water vapor and carbon dioxide, plus other trace gases.

Where is about 99 percent of the atmosphere found, and how thick is it?

Within about 30 km (19 miles) of Earth\'s surface; the atmosphere is very thin overall.

What keeps Earth warmer than it would be otherwise and what are the main greenhouse gases?

The greenhouse effect; water vapor and carbon dioxide are major greenhouse gases, along with methane and nitrous oxide.

Why is stratospheric ozone important?

It absorbs ultraviolet radiation, protecting living things from harmful UV.

What is the ozone hole and what causes it?

Seasonal depletion of stratospheric ozone, intensified by chlorofluorocarbons (CFCs).

What are aerosols?

Tiny solid or liquid particles suspended in the air, of natural or human origin.

What is photochemical smog and where does it occur?

Ozone near the surface formed by reactions involving NO2 and hydrocarbons, contributing to smog.

What is the standard atmospheric pressure at sea level?

1013.25 mb (hectopascals), equivalent to 29.92 inches of mercury.

What is air pressure and how is it measured?

The weight of the air above a point; it is measured in millibars, hPa, or inches of mercury.

How does air pressure change with height?

Pressure decreases with height; the decrease is rapid near the surface and slower at higher altitudes.

What is air density and how does it vary with height?

Air density is the number of air molecules in a given volume; it is greatest at the surface and decreases with height.

Explain the lapse rate and give the approximate value for the lower atmosphere.

The rate at which air temperature decreases with height; about 6.5°C per 1000 m (3.6°F per 1000 ft) on average in the lower atmosphere.

What is the isothermal zone in the atmosphere?

A region, around and above 11 km, where the air temperature remains roughly constant with height.

What marks the top of the troposphere and the start of the stratosphere?

The tropopause.

What causes the temperature increase with height in the stratosphere?

Absorption of UV energy by ozone, which heats the layer.

What is the mesosphere known for?

It is the coldest part of the atmosphere, with the top reaching very low temperatures.

What is the thermosphere and why does it feel not hot despite high temperatures?

A region with extremely low density; few molecules mean heat transfer is minimal, so it may not feel hot.

What is the exosphere?

The outermost region of the atmosphere where molecules can escape into space.

What is the ionosphere and what is its significance?

A region with high concentrations of ions and free electrons; it enables long-distance radio communication by reflecting certain radio waves.

Which instrument is used to obtain the vertical distribution of temperature, humidity, and pressure up to about 30 km?

A radiosonde attached to a weather balloon (rawinsonde when winds are included).

What is a sounding?

A plot of the vertical distribution of temperature, humidity, and wind.

What is a radiosonde launch typically used for, and how often are they released?

To obtain vertical atmospheric profiles; released twice daily at many sites.

What are the main layers of Earth\'s atmosphere by temperature profile?

Troposphere, stratosphere, mesosphere, thermosphere, exosphere (in increasing altitude).

Where is the highest concentration of ozone found?

In the stratosphere.

What causes the inversion in the stratosphere?

Ozone heating the air, leading to temperature increasing with height.

What is the tropopause and how does its height vary?

The boundary between the troposphere and stratosphere; its height is higher near the equator and lower toward the poles.

What are jet streams?

Narrow bands of strong winds in the upper troposphere, often associated with boundaries between air masses.

How do wind directions rotate around high and low pressure centers in the Northern Hemisphere?

Around highs, winds rotate clockwise and outward; around lows, counterclockwise and inward.

What is a mid-latitude cyclone?

A large, rotating storm system in the middle latitudes associated with fronts and variable weather.

What is a weather front, and how are cold, warm, and occluded fronts depicted on maps?

A boundary between air masses; cold fronts are blue with triangles, warm fronts are red with half circles, occluded fronts are purple with both symbols.

What are surface weather maps and what features do they show?

Maps showing pressure systems (Lows, Highs), fronts, wind, temperature, precipitation patterns, and wind barbs.

What is a Doppler radar used for in meteorology?

Measuring precipitation intensity and wind characteristics inside storms.

What role do satellites play in meteorology?

Provide data on clouds, storms, day/night, and water vapor distribution to improve forecasts.

What is the main energy source for weather and climate systems on Earth?

Solar radiation drives atmospheric heating and weather patterns.

What is the greenhouse effect and why is it important?

Water vapor and CO2 trap heat near the surface, keeping Earth warmer than it would be otherwise.

What is the Dobson unit (DU) used to measure?

Ozone thickness in the atmosphere; 500 DU equals about 5 mm if brought to the surface.

What is the difference between the homosphere and heterosphere?

Homosphere is the lower, well-mixed part of the atmosphere; heterosphere above contains heavier gases settled at lower altitudes and lighter gases at higher altitudes.

Why would you not survive in the upper stratosphere despite the 21 percent oxygen concentration?

Oxygen is present, but the partial pressure and the overall thin air make breathing impossible without equipment.

What is latent heat and why is it important for atmospheric energy?

Heat released or absorbed during phase changes of water; a major energy source for storms and atmospheric processes.

Name the four most abundant gases in today\'s atmosphere and indicate which varies most by location.

Nitrogen (N2), Oxygen (O2), Argon (Ar), Carbon dioxide (CO2); CO2 varies most by location due to sources and sinks.

What is meant by air mass energy transfer and what instruments help observe it?

Energy transfer in the atmosphere is monitored by models, observations from weather instruments, satellites, and radars.

What is the primary energy source for Earth's atmosphere?

The Sun’s energy drives the atmosphere and weather.

Define weather.

The state of the atmosphere at a particular time and place, described by the weather elements.

List the seven weather elements.

Air temperature, air pressure, humidity, clouds, precipitation, visibility, and wind.

Define climate.

The accumulation of daily and seasonal weather events, including extremes, over a long period.

What is meteorology and where does the term originate?

The study of the atmosphere and its phenomena; the word comes from Aristotle's Meteorologica.

What is the composition of Earth's atmosphere at the surface?

Mostly nitrogen and oxygen, with smaller amounts of water vapor and carbon dioxide, plus other trace gases.

Where is about 99 percent of the atmosphere found, and how thick is it?

Within about 30 km (19 miles) of Earth's surface; the atmosphere is very thin overall.

What are the main components of clean, dry air by percentage?

Nitrogen (N2) at approximately 78\%, Oxygen (O2) at approximately 21\%, and Argon (Ar) at approximately 0.93\%.

What keeps Earth warmer than it would be otherwise and what are the main greenhouse gases?

The greenhouse effect; water vapor and carbon dioxide are major greenhouse gases, along with methane and nitrous oxide.

Why is stratospheric ozone important?

It absorbs ultraviolet (UV) radiation, protecting living things from harmful UV rays.

What is the ozone hole and what causes it?

Seasonal depletion of stratospheric ozone, intensified by chlorofluorocarbons (CFCs).

What are aerosols?

Tiny solid or liquid particles suspended in the air, of natural or human origin.

What is photochemical smog and where does it occur?

Ozone near the surface formed by reactions involving NO2 and hydrocarbons, contributing to smog.

What is the standard atmospheric pressure at sea level?

1013.25 mb (hectopascals), equivalent to 29.92 inches of mercury.

What is air pressure and how is it measured?

The weight of the air above a point; it is measured in millibars, hPa, or inches of mercury.

How does air pressure change with height?

Pressure generally decreases with height; the decrease is rapid near the surface and slower at higher altitudes.

What is air density and how does it vary with height?

Air density is the number of air molecules in a given volume; it is greatest at the surface and decreases with height.

Explain the lapse rate and give its approximate value for the lower atmosphere.

The rate at which air temperature decreases with height; it is about 6.5°C per 1000 m (3.6°F per 1000 ft) on average in the lower atmosphere.

What is the isothermal zone in the atmosphere?

A region, around and above 11 km, where the air temperature remains roughly constant with height.

What marks the top of the troposphere and the start of the stratosphere?

The tropopause.

What causes the temperature increase with height in the stratosphere?

Absorption of UV energy by ozone, which heats the layer.

What is the mesosphere known for?

It is the coldest part of the atmosphere, with its top reaching very low temperatures.

What is the thermosphere and why does it feel not hot despite high temperatures?

A region with extremely low density; few molecules mean heat transfer is minimal, so it may not feel hot.

What is the exosphere?

The outermost region of the atmosphere where molecules can escape into space.

What is the ionosphere and what is its significance?

A region with high concentrations of ions and free electrons; it enables long-distance radio communication by reflecting certain radio waves.

Which instrument is used to obtain the vertical distribution of temperature, humidity, and pressure up to about 30 km?

A radiosonde attached to a weather balloon (rawinsonde when winds are also included).

What is a sounding?

A plot of the vertical distribution of temperature, humidity, and wind.

What is a radiosonde launch typically used for, and how often are they released?

It is used to obtain vertical atmospheric profiles and is released twice daily at many sites.

What are the main layers of Earth's atmosphere by temperature profile (from lowest to highest altitude)?

Troposphere, stratosphere, mesosphere, thermosphere, exosphere.

Where is the highest concentration of ozone found?

In the stratosphere.

What causes the temperature inversion in the stratosphere?

Ozone heating the air due to UV absorption, leading to temperature increasing with height.

What is the tropopause and how does its height vary?

The boundary between the troposphere and stratosphere; its height is higher near the equator and lower toward the poles.

What boundaries separate the main temperature layers of the atmosphere above the tropopause?

The stratopause (between the stratosphere and mesosphere) and the mesopause (between the mesosphere and thermosphere).

What are jet streams?

Narrow bands of strong winds in the upper troposphere, often associated with boundaries between air masses.

How do winds rotate around high and low pressure centers in the Northern Hemisphere?

Around high-pressure centers, winds rotate clockwise and outward; around low-pressure centers, counterclockwise and inward.

What is a mid-latitude cyclone?

A large, rotating storm system in the middle latitudes associated with fronts and variable weather.

What is a weather front, and how are cold, warm, and occluded fronts depicted on maps?

A boundary between air masses; cold fronts are blue lines with triangles, warm fronts are red lines with half circles, and occluded fronts are purple lines with both symbols.

What are surface weather maps and what features do they show?

Maps showing pressure systems (Lows, Highs), fronts, wind, temperature, precipitation patterns, and wind barbs.

What is a Doppler radar used for in meteorology?

It is used for measuring precipitation intensity and wind characteristics inside storms.

What role do satellites play in meteorology?

They provide data on clouds, storms, day/night, and water vapor distribution to improve forecasts.

What is the main energy source for weather and climate systems on Earth?

Solar radiation drives atmospheric heating and weather patterns.

What is the greenhouse effect and why is it important?

It occurs when water vapor and CO2 trap heat near the surface, keeping Earth warmer than it would be otherwise.

What is the Dobson unit (DU) used to measure?

Ozone thickness in the atmosphere; for example, 500 DU equals approximately 5 mm if compressed to the surface.

What is the difference between the homosphere and heterosphere?

The homosphere is the lower, well-mixed part of the atmosphere, while the heterosphere above it contains heavier gases at lower altitudes and lighter gases at higher altitudes due to gravitational separation.

Why would you not survive in the upper stratosphere despite the 21 percent oxygen concentration?

Although oxygen is present, the extremely low partial pressure and overall thin air make breathing impossible without specialized equipment.

What is latent heat and why is it important for atmospheric energy?

It is the heat released or absorbed during phase changes of water, serving as a major energy source for storms and atmospheric processes.

Name the four most abundant gases in today's atmosphere and indicate which varies most by location.

Nitrogen (N2), Oxygen (O2), Argon (Ar), and Carbon dioxide (CO2); CO2 varies most by location due to sources and sinks.

What is the significance of water vapor's concentration variability in the atmosphere?

As a potent greenhouse gas, its high variability (from nearly 0\% in deserts to 4\% in humid tropics) makes it crucial for cloud formation and precipitation.

What is a barometer used for?

An instrument designed to measure atmospheric pressure.

What is meant by air mass energy transfer and what instruments help observe it?

Energy transfer within the atmosphere is monitored by models and observations from various instruments like weather instruments, satellites, and radars.