GEO Exam 1 Chapter 5

The pressure gradient force moves air from higher toward lower pressure, with wind speeding depending on the steepness of the pressure gradient, indicated by the spacing of isobars, closely spaced isobars produce faster winds, widely spaced isobars produce slower winds. The Coriolis effect, caused by Earth’s rotation, deflects air to the right in the Northern Hemisphere and to the left in the Southern Hemisphere, affecting direction but not speed. Near the surface, friction slows wind, and makes it cross the isobars at an angle, moving out of high pressure areas and into low pressure areas. 

Describe the three main components of atmospheric wind: the pressure gradient force, the Coriolis effect, and friction. Discuss how each of these influences the direction and speed of movement.

The Hadley cells are large tropical convection systems where warm air rises at the equator in the intertropical convergence zone, creating a band of low pressure. The air moves toward the poles at high latitudes, cools, and then descends around 30 degrees North and 30 degrees South, forming subtropical highs. From these highs, some air flows back toward the equator as trade winds, while the rest moves toward higher latitudes. This continuous rising, poleward, and returning air circulates heat and shapes the pattern of tropical surface winds and pressure zones. 

Describe and explain the pattern of air movement within the Hadley Cells.

Under normal Pacific circulation, strong trade winds blow warm surface waters westward, piling them near Indonesia and Australia. This movement allows cold, nutrient-rich water to rise to the surface along the coast of South America through a process called upwelling. The warm waters in the west create low pressure and heavy rainfall, while the eastern Pacific remains cooler and drier under high pressure. During an El Niño event, this pattern shifts dramatically. The trade winds weaken or even reverse, pushing warm water back toward South America and suppressing upwelling. This change brings flooding and storms to the eastern Pacific and widespread drought to the western Pacific.

Describe and explain the interrelated factors that make up the El Nino Southern Oscillation

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