Heating of the Earth

Temperature Layers of the Atmosphere

Solar Radiation

Transfer of Energy  Conduction – transfer of heat energy from one substance to another through direct contact.  Convection – transfer of heat energy from place to place by the motion of gas or liquid.

Transfer of Energy

Exploring How the Sun Heats the Earth  Does the sun heat the earth evenly? Why or why not?  No, because of its spherical shape. Not all places on the surface receive the same amount of energy.  Which area of the earth receives the most solar energy (heat)? Why?  Equator, because it gets the most direct sun light.  Which area of the earth receives the least solar energy? Why?  The poles, because it gets the least direct sun light.

Air Pressure  Uneven heating of the Earth creates differences in air pressure.  Air Pressure – Forms from air molecules constantly moving. When they hit and bounce off an object they create air pressure.  Air pressure is measured using a barometer.  The greater the force, the more molecules, the higher the air pressure.  Air pressure and density are related. The higher the altitude the lower the air pressure and density.

Changes in Air Pressure and Density

High and Low Pressure  Air Pressure and Temperature are related.  Warmer areas of the earth’s surface (heated by the sun) create lower pressure. –Ex. the equator –Lower pressure usually means warm humid weather.  Colder areas of the earth’s surface (heated by the sun) create higher pressure. –Ex. the poles –Higher pressure usually means cooler drier weather.  Why does warmer air create lower pressure and vice versa?

Differences in Temperature and Air Pressure  Remember: uneven heating of the Earth creates differences in air pressure.  What do the differences in temperature and air pressure create?  Wind  How do they create wind?  Air wants to move from an area of high pressure to an area of low pressure.

Wind Direction

Sea and Land Breeze Convection Currents

Global Winds  The uneven heating from the poles to the equator create global winds.  At the poles: indirect solar energy; cold temps; high pressure  air sinks and moves towards the equator.  At the equator: direct solar energy; warm temps; low pressure  air rises and moves towards the poles.  The circular movement is called a convection current.

Complex Movement of Global Winds  Why isn’t the air circulation in the atmosphere as simple as one convection current cell in the northern hemisphere and one in the south?  Earth’s rotation affects air movement and wind direction.  The influence of the Earth’s rotation on the movement of air and water is called the Coriolis Effect.  The Coriolis Effect cause global winds to turn:  Northern Hemisphere = clockwise  Southern Hemisphere = counter clockwise

Coriolis Effect

Global Wind Belts and Calm Regions  The curved wind patterns from the Coriolis Effect create: –3 global wind belts  trade winds  westerlies  easterlies –2 calm regions  doldrums  horse latitudes

Jet Stream  The jet stream flows in the upper troposphere from west to east, created by the earth’s rotation and uneven heating.  The jet stream moves air for 1,000’s of km at speeds of 200 km/hr (124 mi/hr)  The jet streams shift seasonally.  The polar jet stream affects our weather by bringing cold air south from Canada and strong storms.  This is where jets fly. The jet stream can affect travel time. –SF to CHI: 4 HR 5 MIN –CHI to SF: 4 HR 50MIN

Jet Stream