What is Climate?

1. What is Climate? Pgs. 68 - 73

2. Weather vs. Climate • Weather is the condition of the atmosphere at a particular time and place. • They will vary from day to day. • Climate is the average weather conditions in an area over a long period of time. • Climate is determined by temperature and precipitation. • Climates around the world are different because of the amount of precipitation they receive and temperature they reach.

3. Latitude • Can you remember looking at a globe or map? • Were there lines on it that were horizontal? • These are lines of latitude. • Latitude is the distance north or south, in degrees, from the equator. • The temperature of an area is related to its latitude. • Generally, the higher the latitude the colder the climate. • The North Pole is much colder than the equator.

4. Why it’s Hot or why it’s Not. • Why is it warmer at different latitudes? • The answer has to do with solar energy. • Solar energy heats the Earth and latitude will determine the amount of solar energy an area will receive. • Solar rays hit the Earth’s surface at the equator at a 90 degree angle. • This is more direct sunlight which gets higher temperatures. • At the poles, the sunlight is less direct, and more spread out over an area. • This is less direct sunlight which gets lower temperatures.

6. Seasons and Latitude • Most of the places in the U.S. consist of four seasons. • Winter is cooler and summer is warmer. • Some areas of the world do not have seasons. • The equator is always warm and does not change much throughout the year. • For us, winter is cooler because we get less sunlight and the sunlight we get is less direct in a day during the Earth’s revolution. • Summer is warmer because we get longer, more direct sunlight in our days. • The tilt of the Earth is the reason we have seasons.

8. Prevailing Winds • Winds that blow mainly form one direction are prevailing winds. • These winds will influence an area’s moisture and temperature. • If the prevailing winds form from warm air, they will carry moisture. • If they form from cool air, they will be dry. • If the winds blow across land, they will be dry. • If the winds blow across water, they will be moist.

9. Geography • Mountains can influence climate as well. • Mountains add elevation to an area and that affects temperature and moisture of the air. • Elevation is the height of the surface above sea level. • Higher elevations have less dense air that cannot hold as much thermal energy. • Higher elevation equals lower temperatures.

10. Mountain Sides • Wet side • Mountains force air to rise and cool, releasing moisture as snow or rain. • This side is typically green and lush due to the large amount of moisture falling. • Dry side • After dry air crosses the mountain it begins to sink and warm. • The air is warm and dry and usually produces a desert. • This side is known as a rain shadow.

12. Ocean Currents • Water has the ability to absorb and release thermal energy. • The circulation of ocean surface currents has an effect on climates. • Surface currents can be warm or cold stream-like movements of water that occur at or near the surface of the ocean. • The surface temperature of the water affects the temperature of the air above it.

13. Current Effects • The Gulf Stream current carries warm water northward to the island nation of Iceland and even as far as Great Britain. • The warm water heats the air and allows for a warmer climate than the area would normally receive. • The same goes for cold water currents in areas like the Pacific coast of the U.S.