Atmospheric Pressure
is the force exerted by the weight of these gas molecules on a unit of area of Earth's surface or on any other body
Ideal gas law
The relationship between pressure, temperature, and density (P=pRT)
P is pressure, p is density, R is constant of proportionality, and T is temperature. Pressure will increase if density remains constant, but temperature increases and that pressure will i
Isobars
Lines connecting point of equal atmospheric pressure
Pressure gradient
Pressure change; force that acts at a right angle to the isobars in the direction of the lower pressure.
Coriolis Effect
Earth's surface appears to deflect to the right in the Northern Hemisphere and to the left in the Southern Hemisphere
Friction
The frictional drag of Earth's surface slows wind movement and so reduces affects of Coriolis effect and reduces wind speed
Wind speed
Wind speed is variable from one altitude to another and from time to time usually increasing with height. Winds tend to move faster above the friction layer.
Anticyclone
A high pressure center. Four patterns:
1. in the upper atmosphere of the Northern Hemisphere, the winds move clockwise in a geotropic manner parallel to the isobars
2. In the friction layer (lower altitudes) of the Northern Hemisphere, there is a divergen
Cyclone
Low pressure center. Four patterns:
1. in the upper atmosphere of the Northern Hemisphere, the winds move counterclockwise in a geotropic manner parallel to the isobars
2. In the friction layer (lower altitudes) of the Northern Hemisphere, there is a dive
Vertical movement of air
A prominent vertical component of air movement is also associated with cyclones and anticyclones. Air rises in cyclones and descends in anticyclones.
Hadley cells
one semi-permanent convective cell near the equator, per hemisphere
Subtropical Highs
high pressure near 30* N and S / result from descending air in Hadley cells
Trade Winds
diverge from subtropical highs, between 25* N or S and the Equator / Easterly winds / most reliable winds
Intertropical convergence zone
convergence of the Trade Winds at Equator, constant storminess / position seasonally shifts, shifts is more pronounces over land
Polar highs
thermal highs that develop over poles, winds are anticyclonic; strong subsidence, arctic desert
Polar Easterlies
regions north/south of 60* of latitude / winds blow easterly and are variable, cold and dry
Polar front
low pressure area between polar easterlies and westerlies at 60 degrees / air mass conflict between warm subtropics and cold polar air / creates polar jetstream
Monsoons
Seasonal reversal of winds, a general sea-to-land movement called onshore flow in the summer and in a general land-to-sea movement called offshore flow in the winter
Sea and Land breezes
Sea breezes during the day; sea breeze blows from sea to land
Land breezes during the night; land breeze blows from land to sea
Valley and Mountain Breeze
Valley breeze during the day; breeze comes from the valley upward to the mountain
mountain breeze at night; breeze come from the mountain, downward on the valley
Katabatic winds
These winds originate in cold upland areas and cascade toward lower elevations under the influence of gravity. Common in Greenland and Antarctica
Foehn and Chinook Winds
Another downward slope, Foehn in the Alps and Chinook in the Rocky Mountains.
The down flowing air on the leeward side is dry and relatively warm, as the wind blows down the leeward slope, it os further warmed adiabatically, and so it arrives at the base
Santa Ana Winds
develop when a cell of high pressure persists over the interior of the western United States for several days. The wind diverges clockwise out of the high, bring dry, warm northerly or easterly winds to the coast. Noted for high speed, temperature, and ex
El Ni�o
an episodic atmospheric and oceanic phenomenon of the equatorial Pacific Ocean, particularly prominent along the west coast of South America
Walker Circulation
circulation pattern causes by the pressure gradient force that results from a high pressure system over the eastern Pacific ocean. When the Walker Circulation weakens or reverses an El Nino results