Convection and Atmospheric Pressure

• Horse latitudes:

30 degrees N & S

• Trade winds, or passats:

NE winds in Northern hemisphere

SE winds in Southern hemisphere

• Air pressure differences

• Coriolis effect – wind deflections as the result of earth rotation

Compare latitudes:

Almaty – 43.25 N

Boston – 41.78 N

Hstory: sailors gave the region name "horse latitudes" because ships relying on wind power stalled; fearful of running out of food and water, sailors threw their horses and cattle overboard to save on provisions.

Blowing from horse latitudes toward the low pressure equator are TRADE WINDS. They quickly move (propel) trading ships across the ocean, the trade winds between about 30° latitude and the equator are steady and blow about 11-13 miles/ h. In the Northern Hemisphere, the trade winds blow from the northeast: NE Trade Winds; in the Southern Hemisphere they blow from the southeast: SE Trade Winds.

Movement of the atmosphere has a reproducible general pattern caused by earth spinning, and heating / cooling at the cooler N and S poles relative to the warmer equator. These conditions produce movement of air around the earth through convection: Hadley cells. Dominant winds: Trade Winds and Westerlies, occur within these convection cells. These forces dictate to a large extent the movement and dispersal of pollutants and other substances through the atmosphere.

Дата добавления: 2015-09-01