Global atmospheric circulation

• Atmospheric circulation involves a number of interconnected circular air movements called cells

  
• Sinking cold air creates high pressure, and rising warm air creates low pressure
• Surface winds move from high to low pressure, transferring heat and moisture from one area to another
• Surface winds curve due to the Earth's rotation and changes seasonally as the tilt and rotation of the Earth causes relative changes in the position of the overhead Sun

  
• Global atmospheric circulation drives the world's weather
• It's couldy and wet in the UK because 50-60°N is close to where cold polar air from the north meets warm subtropical air from the south. These surface winds from the south-west uaually bring warm and wet weather, because rising air cools and condenses forming clouds and rain

  
• It's hot and dry in the desert because most deserts are found at about 30°N and S and south where sinking air means high pressure, little rain, hot daytime temperatures and very cold nights

  
• It's hot and sweaty at the equator because low pressure marks where the Sun is directly overhead. Hot, humid air rises, cools and condenses, causing heavy rain - hence the tropical rainforests