Weather Hazards Flashcards
What is global atmospheric circulation?
The transfer of heat from the equator to the poles by the movement of air
This process is crucial for regulating the Earth’s climate and weather patterns.
What causes air movement?
Differences in air pressure
Winds blow from high pressure areas to low pressure areas.
What are the loops in the global atmospheric circulation system called?
Cells
Each cell has warm rising air creating low pressure and cool sinking air creating high pressure.
How many cells does each hemisphere have in the global atmospheric circulation system?
Three
These cells include the Hadley Cell, Ferrel Cell, and Polar Cell.
What happens at the equator in terms of air movement?
The sun warms the Earth, causing air to rise and create a low pressure belt
This rising air leads to high levels of precipitation.
What occurs 30° north and south of the equator?
Cool air sinks, creating a high pressure belt
This is often where deserts are found due to dry conditions.
What are the winds called that move back to the equator from 30° latitude?
Trade winds
These winds are part of the Hadley Cell circulation.
What effect causes winds to curve due to the Earth’s rotation?
Coriolis effect
This effect influences the direction of wind patterns.
What happens at 60° north and south of the equator?
Warmer surface winds meet colder air from the poles, causing the warmer air to rise and create low pressure
This area is associated with significant weather activity.
What occurs at the poles in the global atmospheric circulation?
Cool air sinks, creating high pressure
The high pressure air is then drawn back towards the equator.
How does global atmospheric circulation affect weather and climate?
It influences precipitation and temperature patterns around the world
For example, equatorial regions are typically wet, while areas at 30° latitude are often dry.
What type of weather is common at the equator?
Hot and rainy
The direct overhead sun leads to high solar radiation and significant cloud formation.
What characterizes the climate at 30° north and south latitude?
Dry air with few clouds and little rainfall
This is typically where many deserts are located.
What does the UK experience due to its location close to 60° north?
Warm rising air brings cloud cover and rainfall
This is due to low pressure systems carried from the Atlantic by westerly winds.
At what latitudes do tropical storms develop?
Between 5 and 30° north and south of the equator
What sea temperature is required for tropical storm development?
27 °C or higher
What is the effect of low wind shear on tropical storms?
Prevents clouds from breaking up as they rise, keeping the storm intact
What role does the Coriolis effect play in tropical storms?
Causes the storms to spin
What happens to a tropical storm when it moves over land or cooler water?
It loses strength due to the cutoff of the energy supply from warm water
When do the majority of tropical storms occur in the northern hemisphere?
From August to October
When do most tropical storms occur in the southern hemisphere?
From December to April
What is the average duration of a tropical storm?
7-14 days
In which direction do tropical storms spin in the northern hemisphere?
Anticlockwise
In which direction do tropical storms spin in the southern hemisphere?
Clockwise