Global Impacts, Essay Example

The differences of global patterns of atmospheric circulation happen for two reasons. The first is that the Earth’s surface is composed of many different materials. Water and land are the two main surface materials. The materials cause different effects of heating a cooling that cause latitudinal pressure zones to be less uniform (Pidwirny, 2011). The second cause is elevation. As altitude increases, pressure centers tend to become more intense.

The equator is considered the warmest place on Earth. This area is considered a zone of thermal lows or intertropical convergence zone (Pidwirny, 2011). This zone takes air from the subtropics, this air then moves into the upper atmosphere due to convergence and convection (Pidwirny, 2011). From here it flows horizontally to the North and South Poles (Pidwirny, 2011). The air is deflected in the upper atmosphere and then begins to move from east to west (Pidwirny, 2011). This is considered the subtropical jet stream (Pidwirny, 2011). This movement causes the air to accumulate. Due to this accumulation, some air is forced back to the Earth’s surface which creates the subtropical high pressure zone (Pidwirny, 2011).

From this zone the air begins to move again. Some of the air moves back toward the equator, completing the system known as the Hadley Cell (Pidwirny, 2011). The air is also deflected by the Coriolis Effect and creates the Northeast and Southeast Trades (Pidwirny, 2011). The air that moves toward the Poles from the high pressure zone is also deflected by the Coriolis Effect, which in turn creates the Westerlies (Pidwirny, 2011).

Upper air winds below generally toward the poles between the latitude of 30 to 60 degrees North and South (Pidwirny, 2011). Again, the Coriolis Effect deflects the winds so that they flow west to east and create the polar jet stream (Pidwirny, 2011). When the subtropical westerlies hit the cold air coming from the Poles the subpolar lows are created. A small portion of this air is lifted back to Ferrell Cell where it then moves down to create the polar high.

In question one we identified the intertropical convergence zone as the warmest place on Earth. This zone is defined as, “A broad area of low atmospheric pressure located in the equatorial area where the northeasterly and southeasterly trade winds converge, extending approximately 10 degrees north and south of the equator (Intertropicaal convergence zone, 2013).” As warm humid air moves in on this zone, it rises and cools forming clouds and causing heavy showers.

In January through July, this zone is found south of the equator (Pidwirny, 2011). At this time the southern hemisphere is tilted toward the sun. This would include areas such as Africa, South America, and Australia. These Biomes are found closest to the equator and when the zone is south of the equator, this area is the warmest, causing the most precipitation, which is in the months of January through July.

When there is more direct sunlight hitting these areas (land heats faster than water), more water evaporates into the air (Rainforest climate, 2001). The warmer the air, the more water vapor that it can hold. As this air rises, it cools causing condensation in the form of rain. This is why the rainy season in the tropical dry rainforest and tropical savanna biomes comes in the warmer months.

References

Intertropicaal convergence zone. (2013). Retrieved April 25, 2013, from The free dictionary: http://www.thefreedictionary.com

Pidwirny, M. (2011, October 1). Global-scale circulation of the atmosphere. Retrieved April 25, 2013, from The encyclopedia of earth: http://www.eoearth.org

Rainforest climate. (2001). Retrieved April 25, 2013, from Blue planet biomes: http://www.blueplanetbiomes.org