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Air Masses. What is an Air Mass?. A huge section of the lower troposphere Contains air of same temperature and humidity Forms in regions of light wind Maintains composition for days Named for source region. If Ground is colder:. Bottom of air mass cooled Causing:
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What is an Air Mass? • A huge section of the lower troposphere • Contains air of same temperature and humidity • Forms in regions of light wind • Maintains composition for days • Named for source region
If Ground is colder: • Bottom of air mass cooled • Causing: -bottom layer to be stable -inversions (trapping dust/pollutants) -poor visibility -condensation occurs (dew/fog/drizzle)
If Ground is Warmer: • Bottom of air mass warmed • Causing: -bottom to be unstable -convection currents occur (Cumulus clds) -air pollution mixed -visibility good - fair weather if low humidity -showers if higher humidity
TYPES OF AIR MASSES • Maritime- (m)- form over ocean-humid • Continental – (c) form over land-dry • Tropical- (T)- form near equator-warm • Polar – (P) – form at high latitudes-cool • Arctic-(A)- form at highest latitudes-cold