Hazardous Earth - Global Circulation Flashcards
How is heat/energy transferred around the world
Circulation cells (through air) and ocean currents
An Atmospheric circulation cell is the enormous circle of air movement transferring heat/energy around the world. How is it powered?
It is powered by the heat of the sun, which is most intense at the equator
How far does hot air rise into the atmosphere at the equator
15 kilometers
What is the Hadley Cell
It’s a large-scale atmospheric convection cell in which air rises at the equator and sinks at medium latitudes, typically about 30° north or south.
When the warm air rises at the equator, does it create low or high pressure
It creates low pressure. Rising air (becoming cooler and under lower pressure) cannot hold as much moisture and that’s why rainfall is high at the equator
why is rainfall high at the equator
Because the sun’s UV heat energy is most intense at the equator, making the hot air rise which creates low pressure. Rising air cannot hold as much moisture and this is why it rains.
why are arid areas found 30 degrees latitude north and south of the equator
Because after the hot air has risen 15km at the equator, it cools and travels north and south where it sinks. When the cool, dry air sinks, it creates high pressure. High pressure conditions have clear skies with little rainfall.
Explain why Tindouf has an arid climate (it is located 30degree north of the equator)
Tindouf is in an area of high pressure created by the atmospheric circulation cell (the Hadley cell). Hot air pushed up at the equator loses its moisture and flows north, cooling and falling at around 30degree north, creating high pressure and dry conditions
Describe how density differences in Oceans transfer heat
The arctic and Antarctic waters are very cold and salty. This cold, salty, dense water sinks. As it sinks, warmer water from lower (warmer) latitudes is pulled in. This is cooled too by the polar temperatures - and the cycle continues
Name two ways Ocean currents transfer heat around the globe
(1) by wind resulting from the atmospheric circulation cells
(2) density differences due to differences in water temperature and salinity
