4B5 Earth's Atmosphere Flashcards
Explain how the atmosphere's structure influences weather and climate, with certain factors shaping meteorological and climatic conditions.
What is the Earth’s atmosphere?
A layer of gases surrounding the planet.
The atmosphere protects life on Earth by providing oxygen, regulating temperature, and blocking harmful solar radiation.
What are the four layers of Earth’s atmosphere?
- Troposphere
- Stratosphere
- Mesosphere
- Thermosphere
Each layer has unique properties and functions, such as weather in the troposphere and UV protection in the stratosphere.
Fill in the blank:
The atmosphere is primarily composed of _________ and oxygen.
nitrogen
Nitrogen makes up 78% of the atmosphere, while oxygen accounts for 21%. The remaining 1% consists of trace gases.
True or False:
The atmosphere is vital for supporting life on Earth.
True
It provides essential gases like oxygen, regulates Earth’s temperature, and shields the planet from harmful solar radiation.
What is the approximate percentage of argon in the Earth’s atmosphere?
About 0.93%.
Argon is a noble gas that contributes to the trace components of the atmosphere but has little effect on atmospheric processes.
What is the primary function of the ozone layer?
To block harmful ultraviolet (UV) radiation.
Ozone molecules (O₃) in the stratosphere absorb and prevent most UV-B and all UV-C radiation from reaching Earth’s surface.
Fill in the blank:
The layer of the atmosphere where most meteors burn up is the __________.
Mesosphere
The mesosphere lies above the stratosphere and below the thermosphere, reaching temperatures as low as -90°C.
True or False:
The thermosphere is the hottest layer of the atmosphere.
True
Temperatures in the thermosphere can reach up to 2,500°C due to the absorption of high-energy solar radiation, though it feels cold due to low air density.
What is the boundary between the troposphere and stratosphere called?
Tropopause
The tropopause acts as a barrier, preventing the mixing of air between the troposphere and stratosphere.
What is the uppermost layer of the atmosphere?
Exosphere
The exosphere extends from the thermosphere to outer space and is where molecules are sparse, gradually transitioning into space.
What gas in the stratosphere causes temperature to rise with altitude?
Ozone
(O₃)
Ozone absorbs UV radiation, causing temperatures to rise in the upper stratosphere.
True or False:
The stratosphere is the coldest layer of the atmosphere.
False
The mesosphere is the coldest layer, with temperatures dropping as low as -90°C.
Fill in the blank:
The chemical formula of ozone is ______.
O₃
Ozone molecules are composed of three oxygen atoms and are crucial for absorbing UV radiation in the stratosphere.
Which atmospheric layer is known for its weather-related activity?
Troposphere
The troposphere is the most dynamic layer, with storms, clouds, and precipitation driven by the Earth’s heat and water cycle.
What is absolute humidity?
The total amount of water vapor in the air.
Absolute humidity is measured in grams of water per cubic meter of air and represents the actual water vapor content in the air.
What is the percentage of water vapor in air?
Relative humidity
Relative humidity is affected by both water vapor content and air temperature.
True or False:
Warm air can hold more water vapor than cold air.
True
As temperature increases, the air’s capacity to hold water vapor also increases, which affects relative humidity.
Fill in the blank:
When air reaches 100% relative humidity, it is said to be _________.
saturated
At saturation, condensation occurs, leading to cloud formation or precipitation.
How is relative humidity measured?
Using a hygrometer.
Hygrometers measure the water vapor content in the air and calculate the relative humidity percentage.
What are the three main types of clouds?
- Cumulus
- Stratus
- Cirrus
Cumulus clouds are puffy, stratus clouds are layered, and cirrus clouds are wispy and high-altitude.
There are many more specific kinds of clouds, such as cirrocumulsu or nimbostratus, but these classifications are the most general.
Fill in the blank:
Clouds form when warm, moist air ________ and cools, causing condensation.
rises
As air rises and cools, the water vapor condenses into tiny droplets or ice crystals, forming clouds.
What type of cloud is associated with thunderstorms?
Cumulonimbus
Cumulonimbus clouds are tall and dense, capable of producing heavy rain, lightning, and severe weather.
Which clouds are the highest in the atmosphere?
Cirrus clouds
Cirrus clouds form in the upper troposphere and are made of ice crystals due to cold temperatures.
True or False:
Stratus clouds are often responsible for overcast skies.
True
Stratus clouds cover large areas of the sky and typically produce light rain or drizzle.
What are the four main types of precipitation?
- Rain
- Snow
- Sleet
- Hail
Precipitation forms when water droplets or ice crystals grow large enough to fall to the ground. The kind of precipitation that occurs depends on the temperature at different altitudes.
Fill in the blank:
________ forms when rain freezes while falling through cold air near the ground.
Sleet
Sleet starts as rain but freezes into ice pellets before reaching the surface.
How does hail form?
By repeated updrafts in a thunderstorm.
Hailstones grow as they are carried up and down by strong winds in cumulonimbus clouds. A cycle of freezing and collision with water droplets allows the hail to grow larger and larger. Eventually, it will become too heavy, and precipitate to the ground.
True or False
Snow forms when water vapor sublimates directly into ice crystals.
True
Snow forms in cold clouds where temperatures are below freezing, bypassing the liquid phase.
What is barometric pressure?
The force exerted by the weight of the air.
Barometric pressure is measured using a barometer and influences weather patterns.
What is a sea breeze?
Wind blowing from the sea to the land.
Sea breezes occur during the day when land heats faster than water, creating a pressure difference.
Fill in the blanks:
Wind moves from areas of ______ pressure to _____\__ pressure.
High; low
This movement is caused by pressure differences in the atmosphere, driving air circulation.
What is a land breeze?
Wind blowing from the land to the sea.
Land breezes occur at night when the land cools faster than the sea, reversing the pressure difference.
What is an air mass?
A large body of air with uniform temperature and humidity.
Air masses are classified based on their source regions, such as polar or tropical.
Fill in the blank:
A ______ front forms when warm air meets and rises over cold air.
warm
Warm fronts often bring light rain followed by warmer, clearer weather.
What does a blue line with triangles on a weather map indicate?
A cold front.
The triangles point in the direction the cold air is moving.
Fill in the blank:
H on a weather map represents ______ pressure, while L represents ______ pressure.
High; low
High pressure is associated with clear weather, while low pressure often brings storms.
True or False:
Radar is used to detect precipitation intensity and location.
True
Radar systems use radio waves to identify the size, location, and movement of precipitation.
How does latitude affect climate?
It determines the amount of solar energy received.
Regions near the equator receive more direct sunlight, leading to warmer climates, while higher latitudes receive less sunlight, resulting in cooler climates.
What is the rain shadow effect?
The dry area on the leeward side of a mountain.
Moist air loses moisture as it rises over a mountain, causing rain on the windward side. The dry air descending on the leeward side creates the rain shadow effect, often forming deserts like the Great Basin.
True or False:
Elevation decreases temperature.
True
As altitude increases, air pressure and temperature decrease, leading to cooler conditions at higher elevations.
What are global wind belts?
Large-scale patterns of wind movement.
These wind belts, including trade winds, westerlies, and polar easterlies, distribute heat and moisture globally, shaping weather and climate.
What is the deflection of winds due to Earth’s rotation called?
The Coriolis effect.
The Coriolis effect causes winds and ocean currents to curve due to Earth’s rotation, deflecting to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.
True or False:
Trade winds blow from east to west in the Tropics.
True
Trade winds result from atmospheric circulation and are critical for distributing heat and moisture globally.
What are the main climate zones on Earth?
- Tropical
- Temperate
- Polar
Climate zones are determined by latitude: tropical near the equator, temperate with moderate temperatures and seasons, and polar near the poles with cold temperatures and low precipitation.
Fill in the blanks:
The Arctic climate zone has _____ temperatures and _____ precipitation.
cold; low
The Arctic zone is dominated by ice and tundra landscapes, with extreme seasonal variations in daylight.
Which climate zone is located between 66.5°N and 90°N?
Polar
The polar climate zone experiences extreme cold and long periods of darkness or daylight due to its high latitude.
How do volcanic eruptions affect climate?
They release particles that cool the Earth.
Volcanic aerosols, like sulfur dioxide, reflect sunlight and temporarily lower global temperatures.
What is the impact of variations in solar radiation on climate?
They cause temperature fluctuations.
Changes in solar output, such as during solar cycles, can influence long-term climate patterns.
True or False:
El Niño events lead to warmer ocean temperatures in the Pacific.
True
El Niño disrupts global weather patterns, causing droughts in some areas and floods in others.
How do human activities amplify natural climate changes?
By increasing greenhouse gas emissions.
Burning fossil fuels and deforestation add carbon dioxide to the atmosphere, intensifying natural warming effects.
