Lesson 6

Question 1

How does the UN define drought?

Answer 1

An extended period of deficient rainfall relative to the statistical multi year average for a region

Question 2

How does the National drought mitigation centre in the USA describe drought?

Answer 2

insidious hazard of nature

Question 3

What causes drought?

Answer 3

Dams
lack of rainfall
temperature increase
low soil moisture level
Deforestation

Question 4

What are the 4 main causes of drought?

Answer 4

Socio-economic drought
Hydrological drought
Agricultural drought
Meteorological drought

Question 5

What is hydrological drought?

Answer 5

Occurs when there are deficiencies in surface and subsurface water supplies. A deficiency of precipitation but is usually out of phase with or after the occurrence of meteorological and agricultural droughts. It takes longer for precipitation deficiencies to reach some of the components of the hydrological system

Question 6

What is socio-economic drought?

Answer 6

Occurs when the water demand for social and economic purposes exceeds water availability. This could be the result of weather related shortfall in water supply or the overuse of the available water supplies.

Question 7

How is socio-economic drought diffrent from others?

Answer 7

its occurrence depends on variations of supply and demand.

Question 8

What is agriculture drought?

Answer 8

Insufficient soil moisture to meet the needs of a particular crop at a particular time. It is caused by a number of factors such as precipitation shortages, differences between actual and potential evapotranspiration, soil water deficits and reduced groundwater or reservoir levels.

Question 9

What affect does agricultural drought have on crops?

Answer 9

Can result in crop failure or underdeveloped crops with greatly depleted yields. This drought is typically post meteorological drought but before hydrological drought.

Question 10

What is meteorological drought?

Answer 10

long term precipitation is much lower than normal, but there is no consensus regarding the threshold of the deficit or the minimum duration of the lack of precipitation that turns a dry spell into an official drought. This is region specific.

Question 11

What is the Intertropical Convergence Zone (ITCZ)?

Answer 11

A belt of low atmospheric pressure located around the equator. It moves north or south of the equator seasonally.

Question 12

Due to the high temperatures and high evaporation what does ITCZ cause?

Answer 12

ITCZ causes alternating wet seasons and dry seasons in some regions of the world

Question 13

If this is longer than normal, or emphasised by higher than normal temperatures what can ITCZ cause?

Answer 13

this can result in a high chance of drought.

Question 14

What is El Niño?

Answer 14

A climate pattern that describes the unusual warming of surface waters in the eastern tropical Pacific Ocean. El Nino is the “warm phase” of a larger phenomenon called the El Nino-Southern Oscillation (ENSO)

Question 15

What is El Niño?

Answer 15

A climate pattern that describes the unusual warming of surface waters in the eastern tropical Pacific Ocean. El Nino is the “warm phase” of a larger phenomenon called the El Niño-Southern Oscillation (ENSO)

Question 16

Describe El Niño?

Answer 16

El Niño is a reverse of Walker’s cells where high pressure accumulates above Australia, causing drought like conditions, whilst South America becomes a low pressure centre, at high risk of flooding and intense rainfall.It originated when tropical Pacific Ocean trade winds die out and ocean temperatures become unusually warm.

Question 17

What does El Niño impact?

Answer 17

El Niño has an impact on ocean temperatures, the speed and strength of ocean currents, the health of coastal fisheries, and local weather from Australia to South America and beyond.

Question 18

How often does El Niño occur?

Answer 18

2 to 7 year intervals

Question 19

What is La Niña?

Answer 19

the “cool phase” of ENSO, is a pattern that describes the unusual cooling of South America’s surface waters.

Question 20

Describe La Niña?

Answer 20

La Niña is an intensification of Walker’s cell where Australia has a low pressure system whilst South America experiences drought like conditions due to high pressure formation. It occurs when the trade winds blow unusually hard and the sea temperature become colder than normal.

Question 21

What does La Niña impact?

Answer 21

Winters are wetter and cause above-average precipitation across the Northwest of pacific and drier and below average precipitation in South west of pacific. Cold water causes increased upwelling of deep cold ocean waters numbers of drought occurrence, with more nutrient-filled eastern Pacific waters. It had a greater tendency to trigger intense tropical cyclones as wind direction changes pilling up water between Indonesia and nearby areas as winds from Africa onwards gets blocked.

Question 22

What is ENSO?

Answer 22

The El Niño-Southern Oscillation (ENSO) is a recurring climate pattern involving changes in the temperature of waters in the central and eastern tropical Pacific Ocean.

Question 23

Impacts of El Niño on Australia? (6)

Answer 23

Drought, Wildfire, colder ocean water
1997-98 biggest El Niño
2100 dead
Sever drought
tropical cyclones
Food chains effected.

Question 24

Impacts of El Niño on USA? (6)

Answer 24

Flash flooding, tornados, storms
loss to fisheries
Heat wave
Malaria
$1 billion damage
wildfires