Chapter 6 Outline

Chapter 6 Outline - Chapter 6: Atmospheric and Oceanic...

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Chapter 6: Atmospheric and Oceanic Circulations Wind Essentials Earth’s atmos circulation transfers energy/mass on lg scale; in process, imbalance btwn equatorial energy surpluses/polar energy deficits partly resolved, Earth’s weather process formed, ocean currents produced; air pollutants spread; atmos circ categorized at 3 lvls: primary circulation : General worldwide circ; secondary circulation of migratory high-pressure/low-pressure sys’s; tertiary circulation - incl local winds, temporal weather patterns; meridional flows - winds that move mainly N/S along meridians; zonal flows - winds moving E/W along parallels of lat Air Pressure and Its Measurement Molcs that constitute air create air pressure thru thr motion, size, #- the factors tht determine the temp/ density of air; air pressure product of temp/density of a mass of air; pressure exerted on all surfaces in contact w/air; standard of normal sea-level pressure= 1013.2 millibar - force/sq m of surface area: =29.92 in Hg/101.32 kPa (1 kPa = 10 mb); instrument that measures air pressure= barometer ; Evangelista Torricelli developed mercury barometer ; more compact= aneroid barometer - has sml chamber, sealed, connected to a mechanism attached to a needle on a dial… As air pressure incr/decr, it presses on/relieves pressure fr chamber, moving needle; aircraft altimeter a type of aneroid barometer; normal range of Earth’s atmos pressure ~980-1050 mb Wind: Description and Measurement Wind - horizontal motion of air across Earth’s surface; turbulence adds wind updrafts/downdrafts + vertical component; diffs in air pressure (density) btwn two locations=>wind; 2 main properties - speed, direction; anemometer measures wind speed in kmph/mph/mps/knots; knot = nautical mi/hr: Covers 1 min of Earth’s arc in an hr= 1.85 kmph; wind vane determines wind direction; winds named for direction fr which they originate - wind fr W= westerly wind (blows Eward); Beaufort wind scale - descriptive scale useful in visually estimating wind speed Global Winds Atmos flows of global winds redistribute much energy btwn tropics/polar regs; atmos dominant medium 35°lat-poles in each Hem; ocean currents redistribute heat in zone btwn equator/17 th parallels Driving Forces Within the Atmosphere 4 forces determine speed, direction of winds, working on moving air/ocean currents at Earth’s surface, influencing global wind circ patterns: o Earth’s gravitational force on atmos ~uniform; density decr’s as alt incr’s; w/o gravity, no atmos’ic pressure or atmos o Pressure gradient force drives air fr areas of higher barometric pressure (denser air) lower bar pressure (less dense air), causing winds; w/o pressure grad force= no wind o Coriolis force - makes wind traveling in straight path look as if deflected in relation to Earth’s rotating surface; w/o it, winds would move on straight paths btwn high-/low-pressure areas o Friction force drags on wind as it moves across surfaces- decr w/height above the surface; w/
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This note was uploaded on 06/24/2008 for the course GEOG 1 taught by Professor Okin during the Fall '06 term at UCLA.

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Chapter 6 Outline - Chapter 6: Atmospheric and Oceanic...

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