Download Atmospheric and Ocean Circulation

Atmospheric Circulation
GPH 111
Volcanic debris
from Mt. Pinatubo
spreads worldwide
- covering 42% of
the globe in 60
days
Atmospheric Pressure
and Wind
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Atmospheric Processes
The Nature of Wind
General Circulation of the Atmosphere
Modifications of General Circulation
Localized Wind Systems
Atmospheric Processes
 Pressure, Density, and Temperature
 Mapping Pressure with Isobars
Pressure
and
Density
More Air
Pressure…
What is HIGH pressure, what is
LOW pressure?
What’s an Isobar?
Global Patterns of Pressure…
Sample Pressures…
How does wind work?
 Direction of Movement
 Pressure Gradient
- Wind speed
- Cyclones and Anticyclones
 Coriolis Effect
- Geostrophic Winds (Pressure and Coriolis)
 Friction
Pressure
Gradient
Pressure Gradient:
High to Low Pressure
Pressure Gradient: (again)
High to Low Pressure
High Pressure = Anticyclone
Low Pressure = Cyclone
Coriolis Effect…
This will bend your brain…
Geostrophic Winds
Combined result of pressure gradient
and coriolis effect!
The effect of surface friction…
The effect of surface friction…
Show
movies
Overcomes the balance of pressure gradient
and coriolis by slowing the wind down.
Just the Pressure
Gradient Force
Pressure Gradient and
Coriolis Forces generate
High Altitude
Geostrophic Wind
Friction Force
Extends to a height
of about 1,650ft
General Circulation
of the Atmosphere
 Hadley Cells
 Components of General Circulation
 Jet Streams
- Rossby waves
Hadley Cell…
The most dominant wind patterns on the planet!!!
General Worldwide Circulation…
Components
 Subtropical Highs
 Trade Winds
 Intertropical
Convergence
Zone
 The Westerlies
 Polar Highs
 Polar Easterlies
 Subpolar Lows
Wind Circulation in Profile…
High
Low
High
Low
What are Jet Streams?
Jet streams form along the upper
boundaries of large warm and
cold air masses
Speeds range
between
50 and 300 mph
Consider two side-by-side columns of
air, one warm and one cold. If you rise
1,000 meters in cold air, you would rise
above more air molecules than you
would in warm air. Translated: pressure
falls faster in colder air.
Eventually, this change in pressure
makes a big difference. At the high
altitudes of the jet stream, pressure is
much higher in warm air and the
warmer, “denser” air pushes toward the
cold “thinner” air. The result is wind.
This wind is geostrophic at high
elevations and parallels the isobars,
thus whipping around the planet in the
jet streams
Jet stream
and Pressure
Polar Jet Stream affected by
Rossby Waves
Important for when
we get into Cold
and Warm Fronts,
show movie
Let’s
review
this
stuff
again!
Modifications of
General Circulation
 Seasonal Variations in Latitude
 Monsoons
Seasonal variations in Latitude
Show movie!
The Asian Monsoon…
Localized Wind Systems
 Sea and Land Breezes
Local Winds:
Daytime Sea-Breeze and
Night and Land-Breeze Conditions
Things to Know:
 Define and describe Air Pressure
 World wind patterns, including Hadley Cells,
Westerlies, Trade Winds, etc.
(DIAGRAM)
 Driving forces in the atmosphere including
pressure gradient, coriolis, and friction
 What a geostrophic wind is and where you
find them?
 Cyclones and Anticyclones
 Jet Streams and Rossby Waves
 Local winds: sea-breeze, land breeze
 Seasonal circulation variations due to latitude
and how this generates the Asian Monsoon
Help – Chapter AC