Composition of the Atmosphere

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Composition of the Atmosphere
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Air Density

• Temperature
• Warmer air is less dense than cold air
• Humidity
• Humid air is less dense, dry air is more dense
• Air is Never Completely Dry
• Water vapor is as much as 4 of its volume

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Adiabatic Cooling and Heating

• Air becomes cooler when it expands
• As air rises, it expands and cools
• Air heats up when it is compressed.
• As air sinks, it compresses and heats up
• Warm air holds more water vapor than cold air
• When warm air cools, water vapor condenses and
  forms precipitation

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Earths Heat Budget
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Uneven Solar Heating Latitude
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Convection Currents
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Coriolis Effect

• Any object moving freely across the globe appears
  to curve slightly from it initial path.
• In the N. Hemisphere it curves to the right, in
  the S. Hemisphere it is to the left.
• Observed deflection caused by observers moving
  frame of reference
• Every point on the earths surface moves eastward
  at 15/hour, but points closer to the equator
  move faster than those closer toward the poles

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Latitude and Speed

• Every point on the earths surface moves eastward
  at 15/hour
• But points closer to the equator move faster
  than those closer toward the poles

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Inter-Tropical Convergence Zone
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ITCZ and Monsoons

• Monsoons linked to
• the different specific heats of land and water
• the annual north-south movement of the ITCZ,
  InterTropical Convergence Zone.
• EX In Asia, the landmass draws warm, moist air
  from the Indian Ocean.
• Southerly winds drive moisture toward Asia where
  it rises and condenses to produce a months-long
  deluge

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Sea Breezes and Land Breezes

• Sea breeze Cooler air over the sea moves toward
  land as the land heats up
• Land breeze At night, cooler air on land is
  pushed offshore as warm air from the ocean rises.

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Tropical Cyclones

• Great masses of warm, humid, rotating air.
• Large tropical cyclones are called hurricanes in
  the N. Atlantic and E. Pacificand typhoons in the
  western pacific
• Wind speeds must be in excess of 119 km/hr (74
  mph)
• Generated within one warm, humid air mass
• Strength comes from the heat energy that is
  released when water vapor condenses as liquid.
• Tons of energy
• Rain fall can be 1 inch/hour or 20 billion metric
  tons/day
• One day releases 2.4 trillion kWh, the energy
  needs for the U.S. for 1 year

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