What Controls the Temperature Differences on Earth?

1
What Controls the Temperature Differences on
Earth?
2
Factors that Affect Global Temperature Differences

• Latitude
• Topography
• Proximity to Water
• Large Cities

3
Latitude

• Different areas on the Earth receive different
  amount of solar radiation due to the Earths
  tilt.
• Equatorial latitudes receive the most radiation
• Polar latitudes receive the least

4
Latitude (contd.)

• Reason for the Seasons
• Dec-Feb N-hemisphere points away from sun
• Jun-Aug N-hemisphere points towards sun
• Equator always gets more direct and intense solar
  radiation

5
Latitude (contd.)

• Global wind patterns (aka Hadley cells)
• Air is heated over the equator more than at the
  poles.
• Differential heating causes the warm, low density
  air to rise
• Air sinks at 30 and 90 latitude.
• Colors indicate air temperatures
• Large arrows indicate wind direction

6
Latitudinal Zones

• Tropics
• between 23.5?N 23.5?S
• hot temperatures, humid
• Trade Winds blow from east to west, toward the
  equator
• Polar Zones
• from 90 to 66.5?N S latitudes
• cold temperatures and dry
• Polar Easterlies blow from east to west, away
  from the poles
• Temperate Zones
• between the tropics polar zones
• moderate temperatures
• Can be humid or dry
• Westerlies blow from west to east

7
Topography

• Within each climate zone, topographic features
  affect the climate.
• Structure of the Atmosphere
• Increase in altitude --gt colder, dryer fewer
  molecules to absorb solar radiation

8
Topography Orographic Effect

• Windward Side of Mountains
• air rises, cools, and forms precipitation
• Leeward Side of Mountains
• air descends, heats up, and dries out the land
• rain-shadow deserts

9
Large Bodies of Water

• Higher moisture availability
• Temperatures are more moderate
• Coastal areas are warmer in the winter and cooler
  in the summer

10
Large Bodies of Water (contd)

• Sea Breezes
• Air moves from cool to warm
• Daytime from sea to land
• Night time from land to sea
• Effect of moderating areas temperature and
  raises the humidity

11
Large Bodies of Water (contd)

• Ocean Currents
• Cold currents cool air
• Warm currents warm air
• Air temperatures over land are directly effected
  by temperature of ocean current

12
Large Cities

• Summer temperatures can be 5?C warmer.
• Streets, parking lots, and buildings absorb solar
  radiation.
• Absorbed solar radiation is then re-radiated back
  into the atmosphere as heat.
• Pollution traps heat.