Unit 3 Lesson 4: The Atmosphere

Air pressure

The force produced by air pushing on Earth

Altitude

The height of a point or object in relation to sea level or ground level

Convection cell

A zone of air in which warmer air moves upward in the center and cooler air moves downward at the edge

Coriolis effect

A change in the path of an air or water current due to Earth's rotation

exosphere

The outermost layer of Earth's atmosphere

Greenhouse gas

An atmospheric gas such as methane, nitrous oxide, carbon dioxide, ozone, or water vapor that traps energy from the sun

ionosphere

The part of the thermosphere that causes auroras and reflects radio waves

Jet stream

A river of fast-moving air high above Earth's surface

Land breeze

A wind that blows out to the ocean during the night

Mesosphere

The third layer of the atmosphere (moving away from Earth), and the coldest of the layers

Mountain breeze

A breeze that moves down the sides of a slope at night

Ozone layer

The part of Earth's stratosphere that absorbs most of the sun's ultraviolet (UV) Radiation

Polar easterlies

The winds that blow from the polar regions to the subpolar lows

Sea breeze

A wind that blows in from the ocean during the day

Stratosphere

The second layer of the atmosphere (moving away from Earth), which blocks most of the harmful radiation of the sun

Subpolar low

A zone of low pressure at 60 degrees latitude

Subtropical high

A zone of high pressure located over the oceans between 20 degrees and 40 degrees latitude

thermosphere

The fourth layer of the atmosphere (moving away from Earth)

Trade winds

The winds that blow from the subtropical high toward the equator

troposphere

The layer of the atmosphere closest to Earth, where all the weather occurs

Valley breeze

A breeze that moves up the sides of a slope during the day

Westerlies

The winds that blow from the subtropical high to the subpolar lows

Air mass

A body of air with uniform temperature and humidity conditions extending and traveling for miles in the atmosphere

Cephalopod

Any of a class of mollusks that includes squid, octopuses, and cuttlefish

Climate

The average temperature and precipitation for a particular region

Climate zones

Divisions of Earth's climates into general zones based on average temperatures and average rainfall. Earth's three major climate zones are the polar, temperate, and tropical zones

Clouds

Visible collections of particles of water or ice suspended in the air. Clouds are usually found at an elevation above Earth's surface

Continental Arctic air mass

A body of air with uniform temperature and humidity conditions that originates over land at latitudes near the North Pole

Continental polar air mass

A body of air with uniform temperatures and humidity conditions that originates over land at high latitudes

Continental tropical air mass

A body of air with uniform temperatures and humidity conditions that originates over land at low latitudes

Cyclone

A system of winds rotating inward to an area of low atmospheric pressure

Dew point

The temperature at which condensation begins for an air sample

El Nino

A shift in the wind-driven movement of warm water in the Pacific Ocean that causes extreme disruptions to weather systems all over Earth

ENSO

El Nino Southern Oscillation; the cycle of climatic events that includes both El Nino and La Nina

Equator

The imaginary line drawn through points at equal distances from the North and South poles, dividing Earth into two halves (the northern and southern hemispheres)

Front

A boundary between air masses

Gyre

Circular currents in the world's major oceans

Humidity

The amount of water vapor in the air

Hydrosphere

All of Earth's water, including oceans, surface bodies of freshwater, groundwater, clouds, and the water vapor in the atmosphere

La Nina

A lowering of the sea surface temperature by 3 degrees Celsius to 5 degrees Celsius across the equatorial Pacific Ocean that has extensive effects on the weather in North America

Latitude

Distance north or south of the equator, measured in degrees. The latitude of the equator is 0 degrees, while Earth's North Pole is located at 90 degrees north latitude

Maritime polar air mass

A body of air with uniform temperature and humidity conditions that originates over the ocean at high latitudes

Maritime tropical air mass

A body of air with uniform temperature and humidity conditions that originates over the ocean at low latitudes

Meteorologist

A scientist who studies the atmosphere in order to predict the weather and learn about global climate change

Trade winds

The steady winds that blow in a westerly direction toward the equator in belts located in the tropics, between the equator and 30 degrees north and south latitude

weather

The state of the atmosphere at a given time and place

Weather maps

Maps or charts showing weather conditions over a wide area at a particular time. Data on the maps are gathered from observations at different places at that time

Westerlies

Winds that blow from west to east in belts between 30 and 60 degrees north and south of the equator