EVSC10001 Lecture Notes - Lecture 15: Atmospheric Pressure, Atmospheric Circulation, Subtropical Ridge
11 Jun 2018
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Department
Course
Professor
Tropics warmer than poles
More moist
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Warmer air holds more water than colder air
More vapour near surface
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Hadley Cells
Moist tropical air heated at surface
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Warm air rises -> water vapour condenses to form clouds -> produce rain
leaving air dryer
Location of rainforests
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Coastal areas have rising motion - sinking o other side of mountain
range
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Dry air moves poleward -> cools -> sinks back to surface
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High pressure area at poles - less rain
Defines location of deserts
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Subtropics have sinking motion
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Sub-tropical ridge is further north in winter
N-S progression of Hadley with changes in solar radiation
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Sea level pressure
Low in tropics (rising air/clouds)
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High in mid-latitudes (sinking air)
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Wind
Defined by direction of where it is coming from
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Westerly wind - from West
Mid latitudes
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Easterly wind - from East
Tropics
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m/s -km/h - knots
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Strongest in higher latitudes - from West to East
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Faster over OCEAN (less friction)
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Calm regions in mid-latitudes due to cancellation
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Wind at high altitude
Jetstreams intensify further
Used by airlines to reduce flight time
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Precipitation
S hemisphere summer peak precipitation moves south
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Rainfall peak in tropics
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Atmospheric circulation
Wednesday, 6 June 2018
3:58 pm
