Transcript Climate Factors

Part I
Climate Concepts
WEATHER:
Temporary state of atmosphere
CLIMATE:
Average weather conditions in an area over
a long period of time
PRECIPITATION:
Moisture received as rain, snow,
sleet and hail
What Makes
Some Areas So
Hot?
And Others So
Cold?
Why Are Some
Areas So Dry?
While Others
Extremely Wet?
What Creates Our Climate?
What Creates Earth’s
Climates?
•
•
•
•
•
•
Latitude
Ocean Currents
Wind Patterns
Mountain Barriers
Altitude (elevation)
Proximity to Oceans
Part II
Earth’s Relationship with the Sun
The angle of the sun's rays and the surface of the earth
varies with latitude
Sunlight that strikes a surface at an angle is spread over a
larger area than sunlight that strikes the surface directly
Sun’s Angle Varies by Season
TROPIC OF CANCER (23½oN)
TROPIC OF CAPRICORN (23½oS)
The northern most and southern most points on which
the direct rays of the sun fall on the earth
Tropics
Regions that lie between the Tropics of Cancer and
Capricorn that are generally warm and wet
ARCTIC CIRCLE (66½oN)
ANTARCTIC CIRCLE (66½oS)
North of the Arctic Circle and south of the
Antarctic Circle where there is 24-hour sunshine in
summer and 24-hour darkness in winter
Solstice
• Twice a year when Earth’s poles point at
their greatest angle towards or away
from the Sun (around June 21 and
December 21)
Equinox
• Twice a year when Earth’s poles are
equal distance from the Sun (around
March 21 and September 23). A time
of equal light and darkness on Earth.
Part III
Climate Factors
L ATITUDE
O
W
M
A
P
Climate Factors
L ATITUDE
O
W
M
A
P
Sun's rays strike earth most directly over
the tropics, so temps are warmer near the
equator and cooler towards the poles
Part III
Ocean Currents
Climate Factors
L ATITUDE
O CURRENTS
W
CEAN
M
A
P
Sun's rays strike earth most directly over the tropics,
so temps are warmer near the equator and cooler
towards the poles
Prevailing Ocean Currents
Bring warmer or cooler temperatures than normally expected
Ocean Currents Effect Climate
Winds blow off them warming or cooling nearby
areas as well as bringing precipitation
Warm Ocean Currents
Southern Alaska experiences long, mild summer days
because of latitude and warm ocean currents
Infrared
aerial satellite
photo shows
variation in
ocean
temperatures
Climate Factors
L ATITUDE
O CURRENTS
W
CEAN
M
A
P
Sun's rays strike earth most directly over the tropics,
so temps are warmer near the equator and cooler
towards the poles
Climate Factors
L ATITUDE
O CURRENTS
W
CEAN
M
A
P
Sun's rays strike earth most directly over the tropics,
so temps are warmer near the equator and cooler
towards the poles
Winds blowing off ocean currents affect
temperatures by making places warmer or
cooler than normally expected
Part IV
Wind
Patterns
Climate Factors
L ATITUDE
O CURRENTS
IND
W PATTERNS
CEAN
M
A
P
Sun's rays strike earth most directly over the tropics,
so temps are warmer near the equator and cooler
towards the poles
Winds blowing off ocean currents affect temperatures
by making places warmer or cooler than normally
expected
Why Does Wind Blow?
What Direction Does Wind Blow?
• Unequal heating on Earth’s surface creates
“high” and “low” pressure
• Cold air is heavy and sinks creating high
pressure
• Heated air rises creating less downward force
(low pressure)
• Winds from high pressure blow in to take the
place of rising air (like a vacuum)
• So wind blows from high to low pressure
High Pressure
• Air pressure is “high” when cool, heavy
air is descending (often too slowly to
feel)
• High pressure is usually associated with
pleasant, dry weather
• Earth’s polar areas consistently have
high pressure because of the sun’s
indirect rays
Low Pressure
• When air is heated it rises creating “low”
pressure
• Low pressure is often associated with
bad weather
• Because it gets more direct sunlight,
Earth’s tropical regions are often
associated with low pressure
• Hurricanes are low-pressure storms that
move towards high pressure
Wind
Patterns
• Water changes
temperatures slower
than air
• As a result, wind
brings cool breezes
from oceans during
the day
• At night winds usually
blows off the land
towards the cooler
ocean
Wind Belts
Wind Direction
• Air does not always flow directly from
high to low
• Since the Earth rotates the winds are
deflected to the right in the Northern
Hemisphere (and to the left in the
Southern Hemisphere)
Coriolis Effect
Prevailing Wind Patterns
Global Prevailing Winds
Polar Easterlies
60oN
Westerlies
o
30 N
Northeast Trade Winds
0
o
Southeast Trade Winds
30oS
Westerlies
Polar Easterlies
60oS
Infrared
satellite photo
showing
moisture
being
delivered by
prevailing
winds
Climate Factors
L ATITUDE
O CURRENTS
W IND
PATTERNS
CEAN
M
A
P
Sun's rays strike earth most directly over the tropics,
so temps are warmer near the equator and cooler
towards the poles
Winds blowing off ocean currents affect temperatures
by making places warmer or cooler than normally
expected
Unequal heating of the earth creates
prevailing winds which bring precipitation
and warm or cool air
Part V
Climate Factors
L ATITUDE
O CURRENTS
W IND
PATTERNS
CEAN
M
A LTITUDE
P
Sun's rays strike earth most directly over the tropics,
so temps are warmer near the equator and cooler
towards the poles
Winds blowing off ocean currents affect temperatures
by making places warmer or cooler than normally
expected
Unequal heating of the earth creates prevailing winds
which brings precipitation and warm or cool air
Altitude
Altitude
• Altitude (or elevation) is the height of
the land above sea level
• Highest: Mt. Everest (29,029’)
• Lowest: Dead Sea (-1369’)
Altitude =
Temps
• Gravity creates a downward pull on
Earth’s atmosphere
• Fewer gases in the air holds less heat
o
• Temperatures decline 1 F for every 300’
increase in altitude (or elevation)
• So high elevations often
cold
Climate Change Based on Altitude
La Paz,
Bolivia
Climate Factors
L ATITUDE
O CURRENTS
W IND
PATTERNS
CEAN
M
A LTITUDE
P
Sun's rays strike earth most directly over the tropics,
so temps are warmer near the equator and cooler
towards the poles
Winds blowing off ocean currents affect temperatures
by making places warmer or cooler than normally
expected
Unequal heating of the earth creates prevailing winds
which brings precipitation and warm or cool air
Temperatures decrease 1oF for every 300'
increase in altitude (elevation). Thinner
air has less ability to hold heat
Part VI
Climate Factors
L ATITUDE
O CURRENTS
W IND
PATTERNS
CEAN
M BARRIERS
A LTITUDE
Sun's rays strike earth most directly over the tropics,
so temps are warmer near the equator and cooler
towards the poles
Winds blowing off ocean currents affect temperatures
by making places warmer or cooler than normally
expected
Unequal heating of the earth creates prevailing winds
which brings precipitation and warm or cool air
OUNTAIN
P
Temperatures decrease 1oF for every 300' increase in
altitude (elevation). Thinner air has less ability to hold
heat
Mountain Barriers
Orographic Effect
Sierra Nevada Mountains
Western Side:
Eastern Side:
WINDWARD
LEEWARD
Sierra Nevada Mountains
Blocks Moisture Coming Off Pacific Ocean
Death Valley
Climate Factors
L ATITUDE
CEAN
O CURRENTS
W IND
PATTERNS
Sun's rays strike earth most directly over the tropics, so
temps are warmer near the equator and cooler towards
the poles
Winds blowing off ocean currents affect temperatures
by making places warmer or cooler than normally
expected
Unequal heating of the earth creates prevailing winds
which brings precipitation and warm or cool air
M OUNTAIN
BARRIERS
The orographic effect of mountains causes
precipitation to fall on one side (windward)
leaving the other side dry (leeward)
A LTITUDE
P
Temperatures decrease 1oF for every 300' increase in
altitude (elevation). Thinner air has less ability to hold
heat
Part VII
Climate Factors
L ATITUDE
O CURRENTS
W IND
PATTERNS
CEAN
M BARRIERS
A LTITUDE
OUNTAIN
P ROXIMITY
TO OCEANS
Sun's rays strike earth most directly over the tropics,
so temps are warmer near the equator and cooler
towards the poles
Winds blowing off ocean currents affect temperatures
by making places warmer or cooler than normally
expected
Unequal heating of the earth creates prevailing winds
which brings precipitation and warm or cool air
The orographic effect of mountains causes
precipitation to fall on one side (windward) leaving the
other side dry (leeward)
Temperatures decrease 1oF for every 300' increase in
altitude (elevation). Thinner air has less ability to hold
heat
Proximity to Oceans
• Ocean temperatures change little during
the year
• Winds blowing off oceans are rarely
extremely hot or cold
• Places near oceans often experience
moderate temperatures (whether
there’s ocean currents or not)
Proximity to Oceans
Geographic Center of No. America
Continentality
Continentality
Continentality = 4 Seasons
Continentality in Minnesota
Climate Factors
L ATITUDE
O CURRENTS
W IND
PATTERNS
CEAN
M BARRIERS
A LTITUDE
OUNTAIN
P ROXIMITY
TO OCEANS
Sun's rays strike earth most directly over the tropics, so
temps are warmer near the equator and cooler towards
the poles
Winds blowing off ocean currents affect temperatures
by making places warmer or cooler than normally
expected
Unequal heating of the earth creates prevailing winds
which brings precipitation and warm or cool air
The orographic effect of mountains causes precipitation
to fall on one side (windward) leaving the other side dry
(leeward)
Temperatures decrease 1oF for every 300' increase in
altitude (elevation). Thinner air has less ability to hold
heat
Distance from oceans causes greater
seasonal range in temperatures known as
continentality. Nearness moderates temps
Wind Belts