Download Factors that Affect Air Pressure

Pressure Changes
with Altitude
State the relationship
between height
(altitude) and pressure
Pressure reduces in half for
each ______
5 km
1% of the atmosphere
10% of atmosphere
Air Pressure Is Proportional to Density
(density is how “packed” the molecules are per unit area)
At HIGH altitudes,
the air is “thin”,
Pressure is less
At LOW altitudes, near
the surface, there are
more air molecules, so
pressure is greater.
Factors that Affect Air Pressure
Density
Temperature
(altitude or elevation)
Weatherbug graph activity
Humidity
(water vapor))
Pressure Changes with Temperature
Cold air contains slow
moving molecules that are
packed closely together
(very dense) and exert HIGH
pressure.
Warm air molecules
have a lot of energy,
are widely spaced
apart – less dense,
and exert less, LOW
pressure.
Air Pressure and Aviation
Altimeter: measures altitude by detecting change in
air pressure
Temperatures vary due to UNequal
heating of earth’s surface
Earth’s
seasonal
orbit
around the
Sun
Thickness of Earth’s
atmosphere
Angle of the sun
23.5 degree tilt on axis
Temperature changes with
Humidity (water vapor in the air)
Increase in water vapor (humidity) causes…
14 x 2 and O2 _______
16 x 2
Air: N2 _____
Water vapor: H2O
1 x 2 Oxygen ______
16
2 Hydrogen ____
air to be LESS dense = less, LOW pressure
= 60
= 18
Relative Humidity and air Pressure
Upper atmosphere winds
(Jet Stream)
Upper Air-flow patterns cause
Surface High and Low pressure
https://www.youtube.com/watch?v=aiYyCurh_SU
WGN explains
Convergence and Divergence
Air converges, piles-up and
is forced upward.
More air in a taller column
Causes vertical clouds and precipitation
Cold air sinks, and is forced to spreadout at the surface.
No clouds form – clear, fair weather
http://darktimeschronicle.wordpress.com/what-are-high-and-low-pressure-systems/
Cyclone
Anticyclone
What direction is this cyclone rotating?
Cyclonic Circulation
in the Northern and Southern Hemispheres