Weather and Climate

1. Weather and Climate Chapter 3

2. Factors Affecting Climate • Weatheris the condition of the atmosphere at a given time and place. • Weather conditions in a geographic region over a long time are called climate.

3. Factors • The Sun heats the Earth unevenly. • The tilt of Earth as it revolves around the Sun is very important. • It determines which hemisphere receives the Sun’s most direct rays at a given time of year. • This process causes the changing seasons.

4. What happens to the Sun’s energy when it reaches Earth? • ½ is reflected back into space or absorbed by the atmosphere • Earth’s surface absorbs the other ½ • Once absorbed, solar energy is converted into heat. • The measurement of heat is called temperature.

5. Global Wind Belts • Some areas of the world have winds that blow from the same direction most of the time. These winds are called prevailing winds. • Doldrums- area with no prevailing winds. • Front occurs when two air masses of different temperatures or moisture levels meet.

6. Weather Factors • evaporation- the process by which water changes from a liquid to a gas. • humidity- the amount of water vapor in the air. • condensation- is the process by which water vapor changes from a gas into liquid droplets.

7. Mountain Effects • Orographic effect- occurs when moist air pushes against a mountain. The barrier forces the air to rise. The rising air cools and condenses, forming clouds and causing precipitation.

8. Rain Shadow • The side of the mountain facing the wind receives a great deal of moisture. This side is known as the windward side. • The side of the mountain facing away from the wind is the leeward side. As the air moves down the leeward side, it warms and dries. • This drier area is called a rain shadow. Deserts are often located in rain shadows.

9. Storms • Hurricanes are the most powerful and destructive tropical cyclones. They begin over warm tropical areas. • Hurricanes are called typhoons in the western pacific can create dangerous high waves.

10. Climate • Tropical Humid- is found in areas close to the equator. • Tropical wet and dry- just to the north and south of the tropical humid climate is the tropical wet and dry climate. It is sometimes called the tropical savanna climate. • Arid- most arid, or desert, climate regions are centered at about 30 degrees north and south of the equator.

11. Climate • Semiarid- is a transition zone between the arid climate and the more humid climates. • Mediterranean- exists in two areas….one is along coastal areas of southern Europe. The other is along west coast of continents with cool ocean currents. • Humid Subtropical- is found on the eastern side of continents where there are warm ocean currents.

12. Climate • Marine West Coast- heavily influenced by oceans, is generally found on the west coasts of continents in the upper middle latitudes. • Humid Continental- found in the interiors and east coasts of upper-middle latitude continents. • Subarctic- located generally about 50’ nort latitude.

13. Climate • Tundra- Coastal areas in high latitudes have a tundra climate. They also have long winters. • Ice Cap- found in earth’s polar regions, always covered by huge flat masses of ice and snow. • Highland- can have varying climates b/c temperatures change with elevation.