Many factors influence global and local climates over a range of time spans. Download this PowerPoint to look at an overview of the natural influences on climate. Also look at this website for more information
Surface Features
The image to the left shows what happens to the energy from the sun that reaches the Earth's surface. Areas in white and red indicate more reflection of the sun's rays. Around 84% of the energy from the sun incident on ice is reflected. Areas in green and yellow absorb more of the sun's rays. Only about 14% of the energy from the sun incident on dark green forests is reflected. |
The topography of the land can also influence climate in more localised regions. Moist air moving over land can be pushed upwards by areas of higher altitude. This cools the air causing water vapour to condense, cloud formation and precipitation. The now dry air that exists on the other side can cause a desert region where little precipitation occurs. This is one leading factor that causes the climate in the Atacama desert in Chile. |
Atmospheric Gases
Click the image to the right to open a simulator that models the greenhouse effect. You can see how changes in the concentration of greenhouse gases affects the temperature of the surface of the Earth. You can compare this to a greenhouse and also see how greenhouse gas molecules absorb and re-emit heat.
|
Not all atmospheric gases contribute to the greenhouse effect. Those shown above do (and even then, they contribute to different extents).
|
Orientation of the Earth
|
The Earth's axis is tilted at an angle of around 23.5 degrees. Because of this, the concentration of energy from the sun differs throughout the year as the Earth orbits the sun (that's why it's winter in the Northern Hemisphere at the same time when it's summer in the Southern Hemisphere). This website can help in understanding the cause of the seasons too. Due to the variation in temperature (and the flow on effects to evaporation, wind currents, ocean currents, etc...) the weather during different parts of the year varies too.
|
Ocean Currents
|
El Nino and La Nina:
These are phenomena associated with currents in the Pacific Ocean. The video's below help explain what they are and what they do. The first video on the left explains what is happening during El Nino and La Nina events. The second video on the right describes some of the effects of these events. Find out more here on the National Geographic website.
|
|