Questions for Today:  What is Weather and Climate?  What are four major factors that determine Global Air Circulation?  How do Ocean Currents affect Climate?

Weather and Climate  Weather is an area’s temperature, precipitation, humidity, wind speed, cloud cover, and other physical conditions of the lower atmosphere over hours or day. “Climate is what we expect, weather is what we get.” Mark Twain Mark Twain

Weather and Climate  Climate is a region’s general pattern of atmospheric or weather conditions over years or decades or centuries. –Two main factors determine climate  Average Temperature  Average Precipitation –Two Minor factors:  Latitude (Distance from the equator)  Elevation (Height above sea level)

Major Climates  8 Major Climate Zones: –Polar (ice) –Subarctic (snow) –Cool Temperate –Highland –Warm Temperate –Dry –Tropical –Major Upwelling Zones

Major Climate Zones

Solar Energy and Global Air Circulation  The amount of solar energy reaching an area can affect a local climate.  The amount of solar energy and the way the earth rotates caused a cyclical heating and cooling of the earth’s atmosphere and air. –Warm air rises, cool air falls.  Global Air Circulation

Global Air Circulation  4 major factors determine Global Air Circulation: 1.The Uneven heating of the earth’s surface 2.Seasonal Changes in temperature and precipitation 3.Rotation of the earth on it’s axis 4.Properties of air, water, and land.

4 major factors explained  “Uneven heating of the earth’s Surface” –The energy and heat at the equator is more concentrated than at the poles. –Tropical Zones exist closer to the equator than the Poles.  “Seasonal changes in temperature and precipitation” –Due to earth’s tilt on its axis, season’s are created dependent on the distance an area is from the equator  Also creates opposite seasons in the northern and southern hemispheres.

4 major factors explained  “Rotation of the earth on its axis” –Since earth rotates on its axis, the equator spins faster than the polar regions.  The Coriolis effect is created –Creates cells and prevailing winds  Major surface winds that blow almost continuously and distribute air, moisture, and dust over the earth’s surface.

4 major factors explained  “Properties of air, water, and land” –Heat from the sun evaporates ocean water and transfers heat from the ocean to the atmosphere.  Creates cyclical convection cells that circulate air, heat and mositure.

Coriolis Effect

Ocean Currents  The major Ocean Currents also affect the climates of regions.  Ocean water absorb heat from the air circulation.  Ocean currents flow clockwise in the Northern hemisphere, and clockwise in the Southern Hemisphere.

Major Ocean Currents