1. Weather Factors

2. Energy From the Sun
Where does the heat come from? It comes from the Sun. This energy travels to Earth as electromagnetic waves. This energy is in the form of visible light, infrared radiation and ultraviolet radiation.

3. Ultraviolet radiation.
What type of radiation has wavelengths that are shorter than visible light?
Ultraviolet radiation.

4. Energy in the Atmosphere
Some sunlight is absorbed or reflected by the atmosphere before it can reach the surface.
What percentage of Sun’s energy is absorbed by the surface of the earth?
About 50 %.
About 50 %.

5. Greenhouse Effect
The process by which gases hold heat in the air is called the greenhouse effect. What gases trap heat in the air? Ans: CO₂, CFCs, methane, water vapor.
Ans: CO₂, CFCs, methane, water vapor

6. Heat Transfer
Look at the diagram and identify how the heat is transferred in the troposphere?
Conduction, convection and radiation.
Conduction, convection and radiation.

7. Winds
A wind is the horizontal movement of air from an area of high pressure to the area of low pressure. These causes convection currents.

8. Measuring Wind
Winds are described by their speed and direction. The instrument that measures speed is called anemometer.
Wind Vane
East.
Toward what direction does a west wind blow?
East.

9. Wind-Chill Factor
There are 25⁰C outside, but with a strong wind you would feel like 10⁰C!

10. Local Winds
Local winds are winds that blow over short distances. They are divided into sea breeze and land breeze.
How does the wind blow during a hot sunny day?
From sea to land.
How does the wind blow during a cool night?
From land to sea.
What type of breeze occurs during the day?
From sea to land.
Sea breeze.
What type of breeze occurs at night?
Land breeze.

11. Global Winds
Global winds are winds that blow from specific directions over long distances Global Convection Currents
Global Convection Currents

12. The Coriolis Effect is when global winds do not follow a straight path from poles to the equator because of Earth’s rotation.

13. Global Winds Belts There are 3 major global wind belts: Trade winds
Prevailing westerlies
Polar easterlies
In which global wind belt is Thailand located?
Northeast Trades
Northeast Trades

14. Water in the Atmosphere
Water always move in the atmosphere and this is called the water cycle.
What is evaporation?
It is when water changes into water vapor (gas).
What is condensation?
It is when water vapor changes into water droplets.
It is when water
What is precipitation?
It is when heavy water droplets fall to the ground.

15. Humidity
Humidity is a measure of the amount of water vapor in the air. Relative humidity is the percentage of water vapor in the air at a particular temperature.

16. Relative humidity can be measured with a psychrometer.

17. Clouds
Clouds form when water vapor in the air condenses to form liquid water or ice crystals. Ans: cooling and particles in the air.
What 2 factors are required for condensation to occur?
What 2 factors are required for condensation to occur?

18. Types of Clouds Which 2 types of clouds bring precipitation?
Ans: Cumulonimbus and Nimbostratus
Which 2 types of clouds bring precipitation?
Ans: Cumulonimbus and Nimbostratus

19. Cirrus Clouds
Cirrus clouds are feathery clouds that form at high levels (6 km). Usually they predict stable weather.

20. Cumulus Cumulus clouds look like cotton. Predict stormy weather.
Predict stable weather.
Predict stable weather.

21. Cumulonimbus
These clouds bring heavy rain, hail, lightning, thunder and sometimes violent tornadoes!

24. Stratus
Stratus clouds are flat layers that cover all or most of the sky.

25. Altocumulus
Altocumulus and altostratus are clouds that for at high altitude (between 2-6 km). If you see altocumulus in the morning expect thunderstorms in the afternoon.

26. Fog
Clouds that form on the surface of the Earth are called fog.

27. Precipitation
Precipitation is any form of water that falls from clouds.
Precipitation can be in the form of:
Rain
Sleet
Freezing rain
Snow
Hail
Rain

28. Rain
Rain is the most common kind of precipitation.

29. Sleet
Sleet is precipitation in the form of small frozen raindrops.

30. Freezing Rain
Freezing rain is the rain that freezes when it fall on to the surface.

31. Snow
Snow is the precipitation in the form of ice crystals called snowflakes.

32. Hail Hail is the precipitation in the form of ice stones.
Is hail good or bad? Why?
Is hail good or bad? Why?

33. Rain Gauge
An instrument that is used to measure the amount of rainfall is called a rain gauge. The unit of measure is mm mm/year
What is the average rainfall in Bangkok per year?
What is the average rainfall in Bangkok per year?