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Study Guide- Weather and Climate
Vocabulary
Atmosphere- The layer of air that surrounds Earth.
Air pressure- The weight of the air.
Humidity- A measure of the amount of water in the air.
Precipitation- Any form of water that falls from the clouds, such as rain or snow.
Evaporation- The process by which a liquid changes into a gas.
Condensation- The process by which gas changes back to a liquid.
Local winds- Winds that depend upon local changes in temperature.
Prevailing Winds- The global winds that blow constantly from the same direction.
Air mass- A large body of air that has roughly the same temperature and humidity throughout.
Front- The boundary between air masses.
Climate- The average of all weather conditions for all seasons over a period of time.
Microclimate- The climate of a very small area.
El Nino- A short-term climate change that occurs every two to ten years.
Greenhouse effect- Process by which Earth’s atmosphere absorbs heat.
Global warming- The hypothesized rise in Earth’s average temperature from excess carbon
dioxide.
Know the following Concepts:
Atmosphere:
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The atmosphere is made up of 5 layers, but all weather occurs in only two: troposphere
and stratosphere.
Troposphere- Lowest layer where the majority of weather occurs.
Stratosphere- The second layer. Contains the Ozone layer protects life on Earth by
absorbing some of the sun’s harmful rays.
Measuring Atmospheric Conditions:
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Barometer: Measures air pressure, which is the weight of the air.
Thermometer: Measures the temperature of the air.
Rain Guage: Measures the amount of precipitation.
Hygrometer: Measures relative humidity, which is the amount of water in the air.
Anemometer: Measures wind speed
Weather Vane/Wind Vane: Shows the direction from which the wind is blowing.
Air Pressure:
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Air has different weight.
Warm air is a low pressure air mass. It weighs less than colder air.
Cold air is a high pressure air mass. It weighs more than warmer air.
Water Cycle:
Cloud Types:
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Cirrus clouds are high clouds that look thin and wispy. They are usually associated with
fair weather.
Cumulous clouds look piled up and puffy. They also are associated with fair weather,
though can sometimes produce light rain.
Stratus clouds form as a layer of clouds and are low. They often times produce rain.
Cumulonimbus clouds and very tall and bring severe weather such as thunderstorms
and hail.
Weather is caused due to the uneven heating of Earth’s surface.
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Due to the uneven heating, cold air sinks and pushes warmer air up into the
atmosphere.
This causes our air to be in motion.
Local Winds occur because the air over some land or water heats up faster than
over others.
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Sea Breeze: During the day, land heats faster than the sea. Cool sea air moves toward
the land.
Land Breeze: At night, land loses heat faster than the sea. Cooler air moves toward the
sea.
Prevailing winds occur because the earth as a whole heats unevenly.
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The poles are colder than the equator.
Prevailing winds move weather patterns in certain directions.
Weather Fronts
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The boundary between two different air masses are called fronts
Weather usually forms at fronts
Warm Fronts- Warm air slides up and over colder air. Stratus clouds form and can brin
steady precipitation.
Cold fronts- Cold air pushes underneath warm air, forcing it up and forming
cumulonimbus clouds. Severe storms usually form on cold fronts.
Weather fronts traditional move from west to east across the United States.
Climates
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Climate is the average of all weather conditions over time.
The most important thing determining an area’s climate is latitude. (location on Earth)
Areas closer to the equator tend to have warmer climates, while areas close to the poles
have colder climates.