Geography Exam 2

Geography Exam 2 - Reale 1 Geography Exam 2 Chapters 5-7...

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Reale 1 Geography Exam 2 Chapters 5-7 Study Guide Chapter 5 Atmospheric Pressure - Weight of a column of air “above” surface (pressure is from all sides) - Force exerted by gases - Pressure is greatest at the surface due to gravity - At Sea Level o 14.7 lbs/ sq. in. o Changes with altitude--- pressure decrease and molecules spread farther apart due to adiabatic cooling o Harder to breathe at high altitudes/headaches/nosebleeds - Variations with Altitude o Density/Altitude Increases in density=increases in pressure and vice versa The lower the altitude, the higher the pressure o Lower altitudes Gas molecules are closer and higher pressure o Higher Altitudes Air is less dense Decrease in pressure o Pressure is proportional to air density at that level - Variations with Temperatures o When air is heated, molecules are more agitated which leads to higher pressure o Increases in temperature=increases in pressure and vice versa o Warm air=lower atmospheric pressure o Cold air=higher atmospheric pressure Explanation: warm air rises and as it rises, it spreads and cools. Cold air descends and the warm air molecules become colder What causes wind? - Horizontal Movement - Wind direction identification: direction it comes from o Westerlies blow west to east o Easterlies (Trade Winds) blow east to west - Caused by two pressure systems meeting or unequal pressures - Causes of wind o Unequal heating o Pressure gradients o Wind always blows from high to low pressure - To equalize differences in high and low pressures, wind is formed - Winds are the strongest when the difference is the greatest - High pressure causes isobars at a right angle Low Pressure Centers - Cyclones (rotate counter-clockwise) - Involves warm air - Air spirals inward and upward
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Reale 2 o Adiabatic process - Cloudy, rainy - Goes against coriolis effect High Pressure Centers - Anticyclones (clockwise) - Involves cold air - Air spirals downward and outward o Adiabatic process - Fair weather - Follows coriolis effect Pressure Circulation Patterns - Upper atmosphere: faster winds - Surface: slower winds due to friction - Geostrophic winds: winds are parallel to isobars (upper atmosphere) - Lower atmosphere: not much geostrophic winds because of friction from ground Wind Speed - Determined by pressure gradient o Steep gradient= fast o Gentle gradient= slower - Greater difference between high and low pressures= greater the winds - Atmosphere tries to equalize the pressure differences - On a map: lines are very close together signifying a steep (rapid) change - Wind speeds are higher in February vs. August Hadley Cells - Key to an understanding of the wind patterns on our ideal Earth - On or near the equator, where average solar radiation is greatest, air is warmed at the surface and rises - Creates a band of low pressure, centered on the equator - Air rises over the Equator and is drawn poleward by the pressure gradient. This air ascends to great heights, mostly in thunderstorm up-drafts. -
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Geography Exam 2 - Reale 1 Geography Exam 2 Chapters 5-7...

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