ES271_MacroClimate_II

ES271_MacroClimate_II - Similar Climate ­ Similar...

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Unformatted text preview: Similar Climate ­ Similar Vegetation Similar Climate ­ Similar Vegetation Temperature & Moisture at Equator Temperature & Moisture at Equator Heat Distribution N and S Heat Distribution N and S Air Movement ­ Equator Air Movement ­ Equator • As equatorial air is warmed, it rises, expands, and cools. (Adiabatic cooling) Heavy rains in the equatorial region ­ rainforests often found there. • Tropical Rainforest – Borneo Rainfall in ITCZ Rainfall in ITCZ Air Movement ­30º Latitudes Air Movement ­30º Latitudes • • • • • • Cooled air stops rising, moves poleward and drops. Reaches surface at about 30 degrees No. & So. High pressure area Subtropical Calms or Horse Latitudes. Air warms as it drops (pressure + reradiation) ­ picks up moisture. Major deserts of the earth are in this region. Climate & Biomes Climate & Biomes Coriolis Force Coriolis Force • • An object (or air mass) moving above a rotating disk tends to keep its speed of lateral motion. Surface of the rotating earth moves faster at the equator than toward the poles. – 25,000 miles/day or 1,042 miles/hour at equator – 12,500 miles/day or 521 miles/hour at 60º N or S Rotating Disk Coriolis Force Coriolis Force • • • • An air mass moving south from the pole tends to keep its speed of lateral motion. Slower than surface, so the mass “deflects” to the right in N. Hemisphere In the southern hemisphere it would deflect “left” Winds moving toward the equator therefore become the NE and SE trades Earth rotation Coriolis Force Coriolis Force Coriolis Force and Wind Direction Coriolis Force and Wind Direction • “doldrums” near the equator (5 deg. either side, or about 400 miles north and south). Air coming to replace rising air moves along surface from No. and So. forming the Trade Winds. • Prevailing Wind Prevailing Wind Patterns Annual Temperature Variation Annual Temperature Variation Wind pattern effects Wind pattern effects • Dust Transport West Africa ­­­> Canary Islands West Africa ­­­> Canary Islands Caribbean Caribbean Clear Day Wind from the East Annual World Rainfall Annual World Rainfall Ocean Currents Ocean Currents • • Solar energy, gravity, motion of the earth and winds along with continental masses cause the pattern. NE trade winds push water along and tend to “pile it up” at central America on the Atlantic Coast. Ocean Currents • • • “Piled up” water escapes in the form of the Gulf stream. Coriolis force causes it to deflect right Circular patterns or “gyres” are the result Upwelling Upwelling Ocean Conveyor Belt Ocean Conveyor Belt General Considerations General Considerations • Water tends to move poleward on the east sides of continents and towards the equator on the west sides. Water cools as it moves toward poles, but retains heat (or cold) longer than land masses do. • Deep Currents Deep Currents Air movement cells Air movement cells El Nino Global Climate Variation El Nino Global Climate Variation El Nino Global Impacts El Nino Global Impacts ...
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This note was uploaded on 10/06/2010 for the course ES ES271 taught by Professor Machaut during the Spring '10 term at Colby.

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