| A | B |
|---|
| pressure | the more molecules pushing down; the greater the density |
| mercury | 13.6 times heavier than water |
| air pressure | 29.92 in |
| wind | air in horizontal motion |
| 3 characteristics of wind | air pressure, direction, speed |
| pressure variance with altitude | higher you go - less pressure |
| pressure variance with latitude | high at 90 degrees N or S, and alternates ever 30 degrees. |
| atmospheric air pressure | force of weight pushing down on something; weight of the air pushing down on us. |
| area | force per unit area; weight of air |
| how is pressure measured | force divided by the area (in2 or m2) = Atmospheric Pressure |
| Normal sea-level pressure | 29.92 inches |
| higher altitudes = | less air pressure |
| Isobars | Line that connects the same air pressure of the same value |
| wind direction | where the wind is coming from |
| pressure always moves from | high to low |
| gravity pulls air | down |
| describe the motion of atmospheric pressure | moving high to low |
| Driving 4 driving forces that determine wind, speed and direction | Gravitational Force, Pressure Gradient Force, Coriolis Force, Frictional Force |
| Gravitational Force | Gravitational pull controls direction High to Low |
| Pressure Gradient Force | determines how fast the wind will blow |
| The steeper the pressure | strong winds |
| Coriolis Effect | controls direction of wind; caused by rotation of the earth |
| Frictional Force | controls speed; wind comes into contact with water, land-->high to low latitudes |
| Higher Latitudinal Winds 90-60-30-0 | Move west/deflect |
| Lower to Higher winds 0-30-60-90 | Deflect East |
| 4 hemispheric pressure areas | Polar, Subpolar, Subtropical, Equatorial |
| Polar Pressure Area | High-pressure cells; air temp-cold/dry; |
| Subpolar Pressure Areas | Low-pressure cells; Cool/Wet |
| Subtropical Pressure Area | High-Pressure cells; hot/dry |
| Equatorial Pressure areas | Low-Pressure cells; warm/ wet |
| Hadley Cell | vertical circulation stream up off the equator |
| Jet Stream | fast winds flowing east |
| Local Winds | Land to Water or Water to Land; pressure determines direction |
| Pressure moves | high to low |
| Polar Easterlies | deflect west; pressure moves counter clockwise around lows |
| WesterLies | Clockwise around High Pressure systems |
| NE/SE Tradewinds | Around equator |
| Jet Streams | Polar Jet Stream, Sub Tropical Jet Stream; |
| Wind moves | high to low |
| Types of Local Wind | Land/Water; Mountain-Valley; ITCZ; Catabatic Winds |
| ITCZ | shifts as it follows the sub-solar point; winds converge and winds are lifted up; near equatorial low |
| Monsoon | Summer: India/SE Asia; Winter: Australia |
| Ocean Currents occur | because of differences in air pressure |
| frictional force | wind moving over water; if we know where winds are moving we know where the currents are moving |
| Gyres | general circulation |
| Friction occurs between | air and water |
| if you know the wind systems | you know the wave currents. |
