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Weather and Climate
Weather: The day to day characteristics of atmospheric conditions
over a short period of time, in a local area. Otherwise, what you
get.
Factors meteorologist use to determine the
Weather:
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Air temperature
Air pressure (decreases with elevation)
Wind (moving air)
Humidity (moisture in air)
Precipitation (rain, snow, hail, etc…)
Cloud Cover
Use this information to describe today’s weather
Factors that Affect Climate
Climate: The pattern of atmospheric conditions that
takes place over a large area and over a long period of
time. Otherwise, what you expect.
Factors:
Jet Stream
Bodies of Water
Latitude
Ocean Currents
Wind and Air Pressure
Elevation
Relief
Jet Stream
• In Canada and the United
States the wind travels from
west to east.
• Boundary between the cold
dry polar air and warm
moist tropical air is called
the jet stream
• Where this boundary air
meets often causes storms
Bodies of Water
• Water changes temperature
much slower than land.
• In the summer, water acts as
an air conditioner to keep
temperatures cool.
• In the winter, water acts as a
heater to keep temperatures
warm.
• Therefore, water acts as a
moderator.
Latitude
• As distance from the equator
(latitude) increases, the suns
rays travel farther and hit the
earth surface at an angle which
spreads the suns energy over a
greater area.
• Therefore, polar regions are
much cooler than tropical
equatorial regions.
Ocean Currents
• Warm currents heat the air
above causing a milder wetter
climate
• Cold currents cool the air above
causing cold dry climates, due to
the fact that cold air cannot
evaporate as much water as
warm air.
• Wind blows over ocean currents
on to land
• Therefore, the warm Alaskan
current causes warm wet climate
and the cold Labrador current
causes cool dry climate.
Wind and Air Pressure
• The weight of air is called
pressure
• Wind is caused by the
differences in pressure
• Warm less dense air rises,
cool more dense air falls
• Therefore, the greater the
differences in pressure, the
stronger the wind blows.
Elevation
• As altitude increases, the
corresponding temperature
of air decreases.
• As warm air rises, its
temperature cools causing
condensation (clouds).
• Therefore, that’s why you
get snow on the top of
mountains.
Relief
• Mountains form a natural
barrier that causes air masses
to rise.
• As air is forced to rise it
expands, it becomes less
dense and cools, leading to
condensation
• Therefore, very wet on the
windward side of mountains
and dry on the leeward side.