Monday January 26, 2009 pg. 51 Happy Chinese New Year!  Describe what you know about air masses.

 When air moves over surfaces it takes on the temperature and humidity conditions- - creating an air mass  Air masses can extend hundreds or thousands of kilometers

Thursday, January 29, 2009 pg. 53  Based on what we’ve learned, what causes winds to blow?

 Winds are the result of uneven heating of earth’s surfaces.

Friday, January 30, 2009 pg. 54 (left side) “Climate is what we expect, weather is what we get.”  Write a reaction to this quote.

Why does the wind blow?  Winds are the result of the uneven heating of the earth’s surfaces  Convection- movement of heat through air or water

Land and Sea Breezes  The different rates that land and water change temperature cause wind  Low pressure- air warm and light  Sea breeze- cool air from the water moves to land, daytime, starts over the water  Land breeze- cool land air moves to water, nighttime, starts over the land

Monsoons  Monsoons are powerful land and sea breezes  Change direction with the seasons  India!!  Periods of rain- summer- land heats up and pulls moisture from Indian Ocean

Global Winds  Winds which form between the equator and the poles  Continually forming  Move in a particular direction  Equator and poles not heated evenly by the sun

Circling the Globe  Caused by giant convection currents  Warm air at the equator rises and flows toward the poles  Cold polar air sinks  The radiation of the earth causes these winds to deflect  Trade winds- flow toward equator and turn west  Westerlies- blow west to east  Easterlies- blow east to west  Weather changes occur where they meet

Jet Stream  Jet stream- long narrow “tubes” of air in the upper troposphere  Few hundred kilometers wide  Can go 1/2 way around the earth  Winds- 200 mph  Moves weather in the US from west to east