Download A. Heating the Atmosphere and ocean

Heating the Atmosphere and Ocean
A. Heating the Atmosphere and ocean
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Most energy comes from Sun
  Energy transfer (all 3 involved in atmosphere/ocean)
1. conduction
- transfer heat between adjacent bodies
- works best in solids eg. rock minerals
- air and water poor conductors
2. convection
- movement in gas or liquid
- heating causes that part to expand and rise - lower
density
- cooling cause part to contract, increase
density and descend.
3. radiation
- across space and through matter
  Energy Flow through the Atmosphere-Ocean Environment
  Insolation (IN coming SOLar radiATION)
  places on earth receive a fluctuating supply of energy because
1. 1. Spherical
- sun directly overhead greater intensity
- higher latitudes longer path to travel
2. 2. rotates on a tilted axis
- insolation occurs from sunrise to sunset
- seasonal variation in length of day and insolation
- solstices
- equinoxes
3. 3. elliptical orbit around the sun
-earth closest to sun Jan and furthest away July
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passes through atmosphere and hits gases, dust, and clouds
1. 1. absorb - retention of radiant energy
2. 2. scatter - radiation bouces off in all directions
3. 3. reflect - bounces off in on direction
- albedo of a surface is the proportion of
insolation hitting it that is reflected
  Solar Energy and Earth’s Surface
  earth’s surface reflects or absorbs the insolation
  depends on surface material and their albedo
1. land
- light (high reflection) ie. Albedo of snow 90%
- dark (low reflection) ie. Albedo of
blacktop 5%
2. ocean
- albedo depends on sun’s angle
- vertical albedo 3%
- - 5 degrees over horizon
albedo 50 – 80%
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- oceans take longer to heat up and
are slower to cool down than land
Radiation from ground
 Terrestrial radiation
– – more effective in heating the lower atmosphere than insolation
– – temperature are higher near sea level than they are at altitudes
of several thousand feet.
– – Denser air near ground contains most of the dust particles,
water vapor and other gasses that absorb heat
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Convection – causes warmed air in contact with the ground to rise
Conduction – rocks, soil and water only conduct heat
into few centimeters of atmosphere
Lapse rate – rate at which temperature decreases
with height
environmental lapse rate – particular time place
clam winds
- 6.5C per km
- can change because of differences in heating
and cooling of ground
 Temperature inversion
- cooling near ground on windless and cloudless
conditions at night causes air 10s – 100s meter
to be cooler than air above it
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Clouds play important role
- absorb terrestrial radiation from below and
radiate heat back
- slow the return of heat energy to space and
keep more heat in lower atmosphere
- cloudy nights are warmer than clear nights
  Balance of Energy in the Atmosphere-Ocean
Environment
  Heat Balance
- Heat transfer by conduction, convection, and radiation
maintains a balance of inputs from the sun and
outputs from Earth.
- keeps temperatures in the lower atmosphere at levels
that do not fluctuate wildly.
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Global warming
– – changes in the balance between insolation and
outputs
– – Greenhouse effect
– – Increase in carbon dioxide, dust and water vapour
that absorb terrestrial radiation might result in rising
temperature in lower atmosphere
– – Note: the atmosphere does not have barriers like
a greenhouse NOR can the atmosphere be controlled.
  Global Distribution of Solar Energy
  Tropics – more energy arrives than is radiated back to space surplus
  Polar – radiate out more energy than arrives – deficit
  Balancing mechanism acts to maintain temperatures in
different parts of world
1. 1. horizontal transfer of energy through convection
- air heated in tropics moves poleward
- oceans heated in tropics moves poleward.
B. TEMPERATURE DIFFERENCES ON EARTH
  Isoterms – lines joining places of equal temperature
- generally run along the parallels of latitude
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Water - Nearness to a large body of water
- cool in summer
- moderate in winter
 Altitude
– temperature decrease with alititude
 Latitude
– further away from the equator north or
south the cooler it gets
 Prevailing winds - blowing over land – hot in summer and
cold in winter
 Ocean Currents - warm currents and cold currents
 Continentality
- high annual range of temperatures
- ie. Hot in summer & cold in winter
 Human Activity – localized impacts but impact tiny on total
atmospheric heating