1. Earth Science
Chapter 9

2. Chapter 9
Weather and Climate

3. Lesson 1 What Factors Affect Climate?
Climate is the normal pattern of weather in an area over many years.
Climate in an area is affected by:
Earth’s shape
Tilt of its axis
Geographic features

4. Uneven Heating The Sun’s rays strike Earth at different angles.
The closer the angle to the Sun, the warmer the climate in that area.
Example: The Equator

5. Major Climate Zones Earth has three Major Climate Zones
Tropical, Temperate, and Polar
Their differences are:
Average temperature
Amount of precipitation (rain,
sleet, snow, or hail)

6. Tropical Climate Zones
Occur at the Equator, or areas just North and South of it
Warm temperatures all year round
Often very rainy

7. Temperate Climate Zones
North and South of the tropics
Warm summers, with rain as precipitation.
Winter is cool- very cold, and precipitation falls as snow
We live in a temperate climate
Have 4 seasons

8. Polar Climates Located close to Earth’s North Pole and South Pole.
Very cold year round.
Most precipitation falls as snow.

9. Land and Sea Breezes
Unequal heating of land and water causes Land and Sea Breezes.
Sea Breezes- flow from the WATER towards the land.
Land Breezes- flows from the LAND toward the water.

10. Mountain Effect Mountains can affect precipitation.
Most air flows up the windward side of a mountain.
The windward side receives more precipitation than the leeward side.

11. Ocean and Climates Ocean Currents
Caused by the wind pushing against the ocean’s surface, moving streams of water.
Warm ocean currents move warm water away from the equator toward the poles.
Cold ocean currents move cold water away from the poles and toward the equator.

12. El Niño
The name given to a periodic change in the direction of warm ocean currents across the Pacific Ocean.
Occurs every 5-7 years
Can cause change in climate around the world

13. Lesson 2 How Are Weather Forecasts Made?
Earth’s atmosphere is a mixture of gases that surrounds the planet.
Changes in the air causes changes in weather.

14. Structure of the Atmosphere
Divided into four main layers.
Troposphere-
Closest to Earth
Where almost all weather occurs
Thinnest layer
Contains 75% of gases that make up the atmosphere.

15. Stratosphere Lies above the Troposphere Air is much colder and drier
Contains most of the Planet’s Ozone layer
Absorbs radiation from the Sun

16. Mesosphere
Lies above Stratosphere
Coldest layer of Earth’s atmosphere

17. Thermosphere
Thin layer of Earth’s atmosphere
First layer struck by sunlight

18. Air Masses
An AIR MASS is a huge volume of air that affects weather in a certain area
Can be dry OR humid, and warm OR cold, depending on where it forms

19. Fronts A front is a boundary between two air masses
When two DIFFERENT air masses meet, they create a front.
Warm fronts form when warm air moves into an area, causes light rains
Cold fronts form when cold air moves into an area, usually has heavy rains

20. Observing Weather
Weather is the overall condition of the atmosphere at a given time and place.
Meteorologists are scientists who study weather.
Weather maps display atmospheric conditions.

21. RADAR Radar is a useful tool for observing and forecasting weather
Can be used to create an image of a storm.
Size, direction, amount of precipitation and speed of the storm can be determined

22. Other Weather Instruments
Satellites orbiting the Earth measure data in the atmosphere and relay it to Earth
Thermometers- measure temperature in Celsius or Fahrenheit
Anemometers- measure wind speed
Barometers- measure air pressure
Rain Gauges- collect and measure amount of rain, snow, sleet or hail.
Weather Vane- indicates the direction the wind is blowing