Atmosphere & Ocean Flashcards
Wind
motion of air
-named from direction of origin
Prevailing Winds
prominent wind speed/direction in a particular area
Atmospheric Pressure
-force per unit area that is exerted against a surface by air
with altitude, density and pressure….
DECREASE
Low Pressure, Low density air is…
warm and moist
High pressure high density air is…
cool and dry
1 atmosphere =
1013.25 hPa =1013.25 mb = 14.7 psi
What does wind result from?
differences in pressure and density!
Only true vertical force
Gravity
Pressure Gradient Force
-air flows form high pressure area to low pressure area
Coriolis Deflection
- due to Earth being a rotating sphere
- sets objects in straight path in curved line
Friction
- affects surface flow
- opposes direction of motion
- depends on velocity and viscosity
Higher PGF means
Stronger wind
Isobar
a line of equal pressure
-closer spacing, higher PGF, stronger winds
Diverging, Descending
-high pressure area
Ascending Converging
-low pressure area
for ONLY PGF
- wind would move at right angle from isobars
- direction high -> low pressure areas
Cyclone
-ascending and converging
counter clock wise (NH)
Anticyclone
descending and diverging clock wise (NH)
PGF + Coriolis Force creates
- geostrophic winds
- upper tropospher
Primary Circulation is..
general global circulation
Secondary Circulation is…
migrating high and low pressure systems
Tertiary Circulation
- local winds
- temporal weather
Meridian Circulation Flows
-move north or south along meridians
Zonal Circulation Flows
-move east or west along parallels
PGF + Coriolis + Friction force =
Surface winds
- spiral OUT of high pressure areas
- spiral INTO low pressure areas
warmer air is carried towards..
the poles, and cooler air towards the equator
How many East-West cells per hemisphere?
3!
Equatorial Cell (Pressure, location, weather, winds)
- LOW pressure trough
- heavy rainfall
- trade winds (easterlies)
Subtropical Cell (Pressure, location, weather, winds)
- HIGH pressure
- dry and hot
- strong summer, weak winter
- westerlies and trade winds
Subpolar Cell (Pressure, location, weather, winds)
- Low pressure
- cool and moist
- weak summer, strong winter
Polar Cell (Pressure, location, weather, winds)
- High pressure
- dry and frigid
- Antarctic»_space; arctic
Jetstreams
- concentrated bands of westerly air currents
- upper troposphere, 10-15 km up
- many km wide
- speeds of 400 km/h
Polar Jet stream vs Subtropical Jet stream?
-polar jet stream stronger
Rossby Waves
- jet streams weak in summer
- strong in winter
