Water Cycle Eq2 Flashcards
What are the 4 types of drought in order of severity
Meteorological
Hydrological
Agricultural
Famine
What is the pdsi
Palmer’s draught severity index
Uses temperature and precipitation data to estimate relative dryness
Index spans from -10 to 10
What are Enso cycles
El niño and la nina
What is el nino
Climate cycle that operates every 2-7 years caused by changes to sea surface temperature in the southern Pacific ocean
Causes mass evaporation and precipitation in south east Asia + top end of Australia
Causes drought in south america
What is la nina
Similar to el niño, but causes droughts in south east Asia and top end of Australia, mass evaporation and rainfall in south america
What is itzc
Intertropical convergence zone
Area of low pressure near the equator
Because the earth is tilted, as it moves around the sun, the sun will concentrate it’s energy on the north of the equator, then on the south of the equator
What is a monsoon
A particularly wet season lasting several months and happens in a number of regions around the planet
how can overabstraction cause draught
Water may be extracted at a higher rate than it is being filled naturally, so water will eventually run out
How can water transportation schemes cause increased risk of draught
Moves water away from areas that would naturally have that water
Brazil draught
2014
Physical: High pressure system blocked the route of low pressure systems
Human: people began to illegally extract groundwater causing rs to drop to alarming levels
Brazil draught
2014
Physical: High pressure system blocked the route of low pressure systems
Human: people began to illegally extract groundwater causing rs to drop to alarming levels
Australia draught date and physical causes
2019
Physical: extreme positive Indian ocean dipole caused Indian ocean to become cooler than usual meaning less atmospheric moisture
Australia draught human causes: role of climate change
Climate change is causing extreme positive Indian ocean dipole events to become 3x more common this century if ghg emissions continue
Australian draught human causes: over abstraction of ground water
Water in the great artesian basin is extracted, causing pressure levels to decline so water tables drop
Leads to mound springs drying up
Australian draught human causes: British colonisation
Indigenous people used to have controlled fires to reduce amount of flammable vegetation
Now this has ended, forests are denser and have more flammable vegetation so are more vulnerable to forest fires
