What is Climate?
17-1 pgs. 452-457
April 6, 2015
IN: What is the difference between weather and climate? Describe our climate.

Terms and Objectives:
 Terms:
Climate Weather Latitude
Prevailing winds Elevation
•
•
Surface Currents
 Objectives:
Explain the difference between weather and climate.
Identify the factors that determine climates.

 Climate – the average weather conditions in an area over a long period of time.

What determines climate?
 temperature
 precipitation
 our average temp is 80 and average precipitation is 4”.

What is the difference between climate and weather?
 Time
 Weather is the condition at a particular time and place.
 Weather conditions vary from day to day.

Different parts of the world experience different climates.

Different parts of North America experience different climates.

What are climates so different?
 Latitude
 Wind patterns
 Geography
 Ocean currents

 Latitude – the distance north or south from the equator.

Latitude determines the amount of solar energy a particular area receives.

The sun’s rays strike the Earth’s surface at different angles because the surface is curved.

 Prevailing Winds – winds that blow mainly from one direction.

How do prevailing winds affect our climate?
 In North
America winds tend to blow from the west to the east.
 The prevailing winds move air masses.

Geography
 Mountains
 The Rain Shadow Effect
DIAGRAM in your journals.

 The maritime air mass over the ocean is humid. Prevailing winds blow the air toward the mountains in the east.
 The air cools, becoming saturated as it is forced into higher altitudes. The water vapor condenses, precipitating on the
“windward” side of the mountain.
 As the air crosses the “leeward” side of the mountains, and falls to lower elevations, it warms and any remaining water returns to being vapor creating a dry climate.

 Surface Currents – a streamlike movement of water that occurs at or near the surface of the ocean.

Ocean Currents flow in curved patterns because of the
Coriolis Effect, just like air.

How do ocean currents affect climate?
 Maritime air masses that form over cooler surface currents will hold less water vapor than maritime air masses that form over warm surface currents.
 Regions that are near warm surface currents will have a more humid climate than those near a colder surface current.
 The surface current on the West Coast of the
US flows from Alaska and is cold, while the
East Coast is more humid from a tropical current called the Gulf Stream.

OUT: EXPLAIN WHY NEVADA
IS LARGELY DESERT.