weather hazards Flashcards
What is the definition of the global atmospheric circulation?
Global Atmospheric Circulation is the movement of air around the planet.
How does low air pressure work?
air is rising and blows in an anticlockwise direction around the low (in the northern hemisphere). As it rises and cools, water vapour condenses to form clouds and perhaps precipitation
How does high air pressure work?
As air warms it ascends, leading to low pressure at the surface. As air cools it descends, leading to high pressure at the surface.
How does the Global atmospheric circulation influence the location of certain biomes?
Global atmospheric circulation creates winds across the planet as air moves from areas of high pressure to areas of low pressure
What is a tropical storm?
A tropical storm is a powerful weather system that originates over warm tropical oceans and is characterized by strong winds and heavy rainfall
What are the key features of a tropical storms?
a tropical storm is like a huge whirlpool - a gigantic mass of revolving moist air.
Describe the distribution of tropical storms
As tropical storms require warm oceans, they are normally found in tropical regions between 5° and 30° north and south of the equator where the water is warmest.
What factors are needed for the formation of tropical storms
High sea temperatures of at least 27°C.
Converging winds near the ocean surface forcing air to rise and form storm clouds.
Winds that do not vary greatly with height - known as low wind shear.
How do tropical storms form?
Tropical storms usually form between 5° and 30° latitude. When the ocean surface waters reaches at least 27°C due to solar heating, the warm air above the water rises quickly, causing an area of very low pressure. As the air rises quickly more warm moist air is drawn upwards from above the ocean creating strong winds.
