Global Atmospheric Circulation 🩵 Flashcards
What is global atmospheric circulation caused by?
Different parts of the world heating up differently
What is the main source of heat?
The sun- travels to us through space in the form of radiation
What is the suns radiation absorbed by?
Clouds, atmospheric gasses and the earths surface
Why do some parts of the Earth receive more radiation than others?
Because of the curvature of the Earth
What happens at higher latitudes because of the curvature of the Earth?
The radiation from the sun is spread over a much larger surface area
What happens to the polar regions in winter because of the tilt of the Earth?
They do not receive any daylight
What do we see a lot of in the polar regions?
Snow and ice
What does lots of snow and ice do?
Reflect the solar radiation back into space
What does global atmospheric circulation act as?
An air conditioning system, redistributing the heat, stopping the equator becoming hotter and the poles becoming colder and these latitudes becoming inhabitable
What would happened if the Earth did not rotate and was a simple land mass with no oceans?
We would have a single cell in each hemisphere, where hotter air would rise at the equator and flow towards the poles then sink as it cools and return back to the equator
What is the largest cell?
The Hadley cells
What happens at the Hadley cells?
.at the equator, the warmer less denser air rises, it rises to a height of about 18km and spread out at the troposphere, creating an area of low pressure, the warm air spreads out towards the poles, gradually cooling and sinking as it moves before descending to the surface and flowing back to the equator
What are the smallest cells?
The polar cells
What happens at the polar cells?
Cold, dense air descending in the polar regions creates high pressure, as the air leaves the polar regions, it starts to warm and rise, returning to the poles at high levels
What cell is between the Hadley and polar cells?
The ferrel cells
What is different about the ferrel cells compared to the Hadley and polar cells?
.they are not driven by temperature, they flow in the opposite direction to the Hadley and polar cells
What happens at the ferrel cells?
These cells not only transport heat from the equator to the poles, but also result in semi permanent areas of high and low pressure due to rising and descending parts of the circulation cells, giving us our climactic zones
What does rising air cause?
Areas of low pressure, so these areas see much more rainfall- largest areas of rainforest found near the equator and why the U.K. has a relatively wet climate
What does descending air cause?
An area of high pressure, giving us clear skies and little rainfall, which leads to deserts, 30 degrees north and south of the equator
What is the Coriolis effect?
Because the Earth rotates on its axis, circulating air is deflected toward the right in the Northern Hemisphere and toward the left in the Southern Hemisphere
What are trade winds?
Winds that blow from 30 degrees north or 30 degrees south back to the equator