Global Atmosphereic Circulation/ Tropical Storms/UK Weather Flashcards
What is a definition for weather?
the day to day condition of the atmosphere
What is a definition for climate?
The long term average of weather conditions
What is a high pressure zone?
•Where the cold air sinks
•This is where you get clear skies, temperatures can be warm or cold.
•Air sinks at the North Pole and South Pole. At areas of high pressure, winds on the ground move outwards from these areas
What is a low pressure zone?
•Where the warm air is rising
•You get lots of cloud here because the warm air rises, cools and condenses to form clouds.
•Air rises at the equator. At areas of low pressure, winds on the ground move towards these areas (to fill the space left by the rising air)
Where do winds blow from?
Winds blow from high pressure areas to low pressure areas.
Why is the UK cloudy and wet ?
•Warm air from South of the UK and cold air from North of the UK meet over the UK. There is rising air and low pressure over the UK. Rising air cools, condenses and forms clouds and rain.
•Winds come from the South West,
having travelled across the Atlantic
Ocean, these winds bring warm and wet conditions.
Why is Northen Egypt hot and dry?
•Most of the World’s deserts are found at 30°N and S of the equator where air is sinking and pressure is therefore high.
•Therefore there are few clouds and little rainfall.
•The lack of cloud makes it very hot
during the day, but the heat escapes at night making it very cold.
Why is Northen Brazil hot and humid?
•At the equator air is rising, this is a low pressure zone. The suns rays are most intense at the equator so it is much hotter here than in the UK.
•Hot, rising air cools and condenses to form lots of cloud and rain, it is often cloudy and rainy in these locations.
What conditions are needed for a tropical storm to form?
•sea must be 27°C
•summer and autumn when seas are warm
•8-20N of the equator in tropical reigons
Describe the global distribution of tropical storms:
•near to the equator
•most occur in the Pacific ocean
How are tropical storms formed?
•the sun warms the ocean
to 27°C causing evaporation
•warm air rises, (meaning there is a low pressure zone) cools and condenses drawing in more moisture from the ocean causing strong winds and large clouds
•these large clouds bring lots of intense heavy rainfall
• the coriollis effect causes the air to spin upwards. some cool air sinks back down to create a warm central eye
•air rushes in from higher pressure areas outside of the storm to lower pressure areas at the centre of the storm creating winds
How wide can a tropical storm be up to?
300km
What direction do tropical storms travel in?
•All tropical storms move from East to West because of the way
the Earth spins.
•When they hit land they lose their energy source (the warm moist ocean) and friction increases so the storms start to slow down and die out (decay).
•Once they hit land their direction of travel becomes less predictable but in
the Northern Hemisphere they move North and in the Southern Hemisphere they move South.
Why do tropical storms spin?
•The Coriolis effect makes tropical
storms spin upwards
•They spin to the right in
the Northern Hemisphere (North of the equator) and to the left in the Southern Hemisphere (South of the equator).
How will Climate Change alter the conditions that cause tropical storms to form?
•Sea levels will rise- therefore storm surges (huge coastal waves caused by storms) will become even bigger.
•The atmosphere will become warmer (warm air can hold more water) so heavy rainfall will become
more common.
