Weather hazards Flashcards
What is the atmospheric circulation model?
The movement of air across the planet occurs in a specific pattern. The whole system is driven by the equator, which is the hottest prt of the Earth
What are the 3 cells of circulation?
In this order:
Polar cell
Ferrell cell
Hadley cell
At what altitudes are there high and low pressure?
0 - Low
30 N+S - High
60 N+S - Low
90 N+S High
What are conditions like at high pressure?
- Stable conditions
- Dry
- Air is sinking
What are conditions like at low pressure?
- Unstable conditions
- Air is rising
- Wet
What direction does wind move?
From high to low pressures
Why do winds not just blow up and down?
Due to the tilt on the earth (corealis effect)
What winds meet at the equator
Trade winds meet at the equator to form the Inter-Tropical Convergence Zone (ITCZ)
What is the distribution of tropical storms?
The majority of tropical storms occur between the tropic of Cancer and Capricorn 23.5 degrees N+S
None form at the equator so 5-30 degrees N+S
What are the 3 names for tropical storms?
Hurricanes - Found in America
Cyclones - Indian / SE Asia
Typhoons - Oceania/ Madagascar
What two conditions are required for a tropical storm to form?
Sea surface temperature of 27 degrees Celcius
Low wind shear
What is the relationship between tropical storms and global atmospheric circulation model?
They form at low pressures 5-30 degrees N+S
How to tropical storms form?
- Sea surface temperatures reach 27 degrees Celcius as the sun shines directly upon the areas near the equators
- The warmth cause the air to begin to rise forming and unstable warm air mass
- The air rises to form an low pressure sone
- Cooler air is brought from high pressure areas causing string winds
- The difference in pressures cause the speed of the winds to increase
- The rising air the cools and condenses to form heavy rain clouds
- The storm continues to spiral due to the coriolis effect as it reaches land
When is tropical storm season
June - November
What are the characteristics of tropical storms?
torrential rain
High windspeeds 74mph
intense low pressure
Where is the calmest and strongest part of a tropical storm?
Calmest - eye
Strongest - eye walls
What direction to tropical storms spiral in the north and south equator?
North - anti clockwise
South - clockwise
What types of clouds are formed at tropical storms?
Cumulonimbus clouds
What happens when tropical storms reach land?
Energy is absorbed by land so they slow down
How does climate change affect the distribution, frequency and intensity of tropical storms?
Distribution - casual relationship more originated from the North Pacific and central pacific increased between 1980 -2018, may see more form outside tropics of Cancer and Capricorn
Intensity- Sea surface temperature increases so more energy is used so more intense
Frequency - No overall trend may decrease of high wind sheer and they are broken up early on
A recent extreme weather event int he UK?
16-19th July 2022 heatwave
Social impacts of this weather event?
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