Transcript Weather Instruments

Weather
What do we know about
weather?
How do people measure and predict
the weather?
Meteorologist
• A scientist who studies the weather
• What kind of tools do they use?
Thermometer
• Used to measure temperature
• measures the kinetic energy of air
molecules
• Fahrenheit & Celsius thermometers
Anemometer
• Measures wind speed
• a system of gears converts the number of
turns per minute into wind speed
Hygrometer
• Measures humidity
• the moisture in the air
Weather Vane
• Measures wind direction
• changes in wind usually lead to change in
weather
Barometer
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Measures air pressure
high pressure = clear cool skies
low pressure = cloudy skies, moist air
extreme low pressure = stormy weather
Cloud Conditions
• Observing clouds can tell a lot about the
weather
Cumulus
• White & puffy
• fair weather
Cirrus
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High in the sky
white
thin & wispy
fair weather
Stratus
• Low in the sky
• thick & gray
• usually bring rain
Cumulonimbus
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Tower high into the sky
gray to black
Thunderstorms, hail, tornadoes
anvil shaped
How can rising air pressure lead
to a prediction about weather?
Air Mass
• A large body of air that has the same
temperature and humidity throughout
• take on the characteristics of the region over
which they form
• 4 types in the the USA
Air Masses
– Categorized by moisture content and temperature
– Moisture categories: m = maritime (wet) and c =
continental (dry)
– Temperature categories: P (polar; cold), T
(Tropical; warm)
Continental Polar
• Cool dry weather
Continental Tropical
• Hot dry weather
Maritime polar
• Cool humid weather
Maritime Tropical
• Warm wet weather
Front
• Border where two air masses meet
• most weather changes occur along a front
• cold front = cold air mass moves under a
warm air mass creating cumulonimbus
clouds
• warm front = a warm air mass moves over a
cold air mass forming stratus clouds
What kind of air mass causes hot
humid weather?
Climate
• The regular weather pattern for a region
• precipitation & temperature determine
climate
• seasonal patterns
• all patterns are driven by the sun
• proximity to the equator determines
temperature patterns
?????
• What is the cause of the seasons?
• What are two major factors of climate?
• What kind of climate would you find near
the equator?
• What kind of climate would you find at the
poles?