Drought in Australia
Drought in Australia
Definition:
A drought is a prolonged, abnormally dry period when there is not enough water for users' normal needs. Drought is not simply low rainfall; if it was, much of inland Australia would be in almost perpetual drought. Because people use water in so many different ways, there is no universal definition of drought.
Drought occurs because rains are unreliable and in some years the ITCZ (Inner Tropical Convergence Zone = area of rainfall) may not move so far north. Thus hot, dry tropical continental air dominates for the whole year.
Drought in Australia
Australia is prone to drought because of its geographic location.
Much of Australia lies in a latitude belt that is under the influence of an atmospheric phenomenon known as the subtropical high.
Just outside of the tropics in each hemisphere lies a swath of the globe where air frequently sinks toward the Earth’s surface from higher in the atmosphere.
The air warms and dries as it sinks, creating semi-permanent zones of high air pressure at the surface.
These subtropical highs are areas of stable, warm, and dry air that favour clear skies and little rainfall
Where: most common in the middle of Australia (the lower you go, the drier it gets)
When: Drier than average conditions tend to occur over Australia during periods of El
Nino. This is due to increased amounts of sinking air in that area which acts to suppress rainfall. (El Niño translates from Spanish as 'the boy-child'. Peruvian anchovy fishermen traditionally used the term - a reference to the Christ child - to describe the appearance, around Christmas, of a warm ocean current off the South American coast, adjacent to Ecuador and extending into Peruvian waters.)
Predictibility: * Variable rainfall * Depends on the spatial elements of the area
Magnitude:
* Lack of rain causes * absolute drought (a period of at least 15 consecutive days with less than 0.2 mm of rainfall)
* partial drought (a
Definition:
A drought is a prolonged, abnormally dry period when there is not enough water for users' normal needs. Drought is not simply low rainfall; if it was, much of inland Australia would be in almost perpetual drought. Because people use water in so many different ways, there is no universal definition of drought.
Drought occurs because rains are unreliable and in some years the ITCZ (Inner Tropical Convergence Zone = area of rainfall) may not move so far north. Thus hot, dry tropical continental air dominates for the whole year.
Drought in Australia
Australia is prone to drought because of its geographic location.
Much of Australia lies in a latitude belt that is under the influence of an atmospheric phenomenon known as the subtropical high.
Just outside of the tropics in each hemisphere lies a swath of the globe where air frequently sinks toward the Earth’s surface from higher in the atmosphere.
The air warms and dries as it sinks, creating semi-permanent zones of high air pressure at the surface.
These subtropical highs are areas of stable, warm, and dry air that favour clear skies and little rainfall
Where: most common in the middle of Australia (the lower you go, the drier it gets)
When: Drier than average conditions tend to occur over Australia during periods of El
Nino. This is due to increased amounts of sinking air in that area which acts to suppress rainfall. (El Niño translates from Spanish as 'the boy-child'. Peruvian anchovy fishermen traditionally used the term - a reference to the Christ child - to describe the appearance, around Christmas, of a warm ocean current off the South American coast, adjacent to Ecuador and extending into Peruvian waters.)
Predictibility: * Variable rainfall * Depends on the spatial elements of the area
Magnitude:
* Lack of rain causes * absolute drought (a period of at least 15 consecutive days with less than 0.2 mm of rainfall)
* partial drought (a