Download Weather and Climate

GCM’s
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Uneven Solar Energy
Inputs:Earth is heated unevenly
by the sun due to different angles
of incidence between the horizon
and Sun
This angle of incidence (Angle
the Sun’s rays hit Earth’s surface
Latitude:
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Along the Equator = direct
sunlight; small angle =
amount of sunlight is
concentrated = Hotter
temperatures
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Poles = Large angle =
amount of sunlight is spread
out over a large area =
Colder temperatures
Earth’s tilt on it’s axis causes
the Seasons
Heating of the Earth
Vernal equinox
March 22nd
Winter solstice
Dec 22nd
Autumnal equinox
Sept 22nd
Summer solstice
June 22nd
Solar Radiation and Heating of
the Earth’s surface
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Areas between 0⁰ and
38⁰N/S produce warmer
climates
Areas between 38⁰N/S and
90⁰N/S produce colder
climates
What does this unbalance
of heating create on the
EARTH?
• WIND!
• Wind moves cold air
from the poles towards
the equator and warm
air at the equator
towards the poles
What happens to the
radiation once it hits
the Earth’s atmosphere
and surfaces.
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Solar constant = constant
amount of energy being
received from the Sun by the
Earth = 100%
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Out of the 100% of solar
radiation
47% of incoming is absorbed by
Earth’s surface
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50% of this is transferred to
atmosphere through
evaporation
30% is transferred back into
space
23% is absorbed by
atmospheric
Convection Currents in
the Atmosphere
Solar Radiation is received by the EARTH
Earth’s surfaced is heated through
RADIATION.
CONDUCTION: Air molecule touch
the ground causing the air to heat
up
CONVECTION: Warm air rises,
begins to cool and sink back down
WARM AIR RISES –
COLD AIR SINKS
Pressure
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Convection currents in the troposphere create areas of low pressure
and high pressure.
Low pressure = sucks air in and rises
High pressure = air sinks and is pushed out
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WIND is created because of difference between pressure
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Moves from HIGH pressure to LOW pressure
HADLEY CELL
Discovered in 1735 by
George Hadley – formalized
the wind pattern associated
with trade winds.
- Equator is very HOT due
to direct sunlight all year
- Warm air rises at the
equator (area of low
pressure)
- Reaches the
Tropospause
- Air moves towards the
poles
- Cools and sinks at 30⁰N/S
(area of high pressure)
- Air moves back towards the
equator
- Warming up and continues
Ferrel & Polar
Ferrel
• The in-between convection
cell created in an ideal
model between HADLEY
and POLAR.
• 30-60^N/S
• Between 30⁰ N/S (high
pressure) and 60 ⁰N/S (low
pressure.)
• Mixing of the northern air
mass (cold) and southern
air mass (warm)
• Creation of the
WESTERLIES
Polar cell:
• Between 60 ⁰N/S and 90 ⁰N/S (poles)
• Low pressure at 60 ⁰N/S = air rises
• High Pressure 00 ⁰N/S = air sinks
• Creates Easterlies
Ferrel & Polar Cells
The Atmospheric
Circulation System
Global Winds
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Trade Winds
 0⁰ to 30⁰N/S
 winds move from Equator (low pressure) to 30⁰N/S
(High Pressure)
 Move from EAST to WEST
Westerlies=
 30 ⁰N/S (high) to 60 ⁰ N/S (low)
 Move from WEST to EAST
Easterlies =
 60 ⁰N/S (low) to 90 ⁰N/S (high)
 Move from EAST to WEST
Other Names for the Equator
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Tropics
Doldrums (little to no wind; DULL)
ITCZ (Intertropical Convergence Zone)
Pressure Belts
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ITCZ (Equator) =
LOW Pressure
Horse Latitudes =
30⁰N/S = HIGH pressure
Sub Polar Low= 60⁰N/S
= LOW pressure
JET STREAMS – Rivers of AIR
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Fast flowing, narrow air
currents found in the
atmosphere between 712km
Planes fly in it when
going west to the east
Impacts weather
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Polar Vortex= Jet Stream
dropped low to bring down
cold air from the Polar Cell