Transcript Wind Patterns - Bentworth School District

Wind Patterns
&
Ocean Currents
Wind
• Air moving across land or water.
• Wind occurs when temperature creates
differences in air pressure.
• Near sea level gravity pulls the gasses in
the air closer together increasing air
pressure.
• The air/atmosphere in the mountains is
thinner.
Prevailing Winds
– Winds that blow in a consistent pattern
– These constant winds are divided based on
the latitude in which they occur.
Trade Winds
• Winds that blow
toward the equator
from about 30
degrees N and 30
degrees S latitude.
Westerly Winds
• Winds that blow
between 30
degrees N and 60
degrees N as well
as 30 degrees S
and 60 degrees S.
• They generally
blow in a west to
east direction.
Polar Easterly Winds
• These winds lie
between the North
Pole and 60 degrees
N as well as the
South Pole and 60
degrees S.
• These winds blow
mostly from east to
west and push cold
air down towards the
middle latitudes.
Doldrums
• The area surrounding
the equator (right next
to it)
• There is not much
wind activity here.
• Does not mean
absolutely no wind,
just very little and
non-predictable
Ocean Currents
Ocean Currents
Ocean Currents
• Sea water that flows in the ocean is called
a current. (like a river in the ocean)
• Ocean currents generally move clockwise
in the Northern Hemisphere and
counterclockwise in the Southern
Hemisphere.
Warm Ocean Currents
• Warm water moves from the equator slowly
toward the poles. As it does it gets cooler.
(forming a cold current)
Effects of Ocean Currents
• Because land climate is effected by the water
around it the warm or cold currents help
determine the climate. (Warm or cooler climate)
North Atlantic Drift
• North Atlantic Drift is
a warm current that
flows far north.
• It creates a mild
climate for Northern
Europe.
Labrador Current
• Labrador Current is at
relatively the same
latitude as the N.
Atlantic Drift yet it
makes areas of
Canada and Maine
colder than Europe.
• Ocean Currents that primarily affect the
climates of the USA:
– Gulf Stream—(Warm)
– Labrador Current—(Cold)
– California Current—(Cold)
Landforms affected by Water
• Land cools and heats faster than water.
• Water will retain its heat or coolness for a
much longer time period.
– Example:
• The desert in the Midwest gets extremely hot
during the day and very cold at night.
Landforms affected by Water
• Because water holds it’s heat longer the
area near beaches tends to have warmer
climates.
• Areas near beaches do not have drastic
seasonal changes.
– Example:
– Southern Virginia doesn’t receive much snow
compared to Southern parts of Indiana yet
they are along the same line of latitude.
Mountain Anomalies
Mountain Anomalies
• Wind blowing off the
ocean that hits a
mountain will cause
the air to rise resulting
in precipitation to fall
on the “windward
side” meaning side
that faces the wind.
Mountain Anomalies
• The “leeward side”
is the other side of the
mountain which does
not receive the cool
air or precipitation.
• The leeward side
which receives the
warm dry air causes
this area to have a
“rain shadow”