EQ2

Question 1

define drought

Answer 1

a ‘shortfall’ or deficiency of water over an extended period, usually at least a season

Question 2

define meterological drought

Answer 2

shortfalls in PPT as a result of short term variability within the longer-term average overall

Question 3

define agricultural drought

Answer 3

the rainfall deficiency from meteorological drought leads to deficiency of soil moisture and soil water availability, which has knock on effect on plant growth and reduces biomass

Question 4

define hydrological drought

Answer 4

associated with reduced stream flow and groundwater levels, which decreases because of reduced inputs of PPT and continued high rates of EVP, it results in reduced storage in lakes and reservoirs, often marked with salination and poorer water quality

Question 5

what does PPT stand for (important)

Answer 5

PRECIPITATION

Question 6

what does EVP stand for (important)

Answer 6

EVAPOURATION

Question 7

what are the major features of meteorological drought

Answer 7

Rainfall deficit
-low precipitation
-high temperatures
-strong winds
-increased solar radiation
-reduced snow cover (rivers will not get snowmelt input – rivers drop)

Question 8

what are the major features of hydrological drought

Answer 8

Stream flow deficit
-reduced infiltration (ground is so hard water can’t infiltrate)
-low soil moisture
-little percolation and groundwater recharge decreases

Question 9

what are the major features of agricultural drought

Answer 9

Soil moisture deficit
-low evapotranspiration
-plant water stress
-reduced biomass
-fall in groundwater levels

Question 10

what are the major features of famine drought

Answer 10

Food deficit
-loss of natural vegetation
-increased risk of wildfires
-wind-blown soil erosion
-desertification

Question 11

what are the major impacts of meteorological drought

Answer 11

-loss of soil moisture
-supply of irrigation water declines

Question 12

what are the major impacts of hydrological drought

Answer 12

-reduced storage in lakes and reservoirs
-less water for urban supply and power generation - restrictions
-poorer water quality
-threats to wetlands and wildlife habitats

Question 13

what are the major impacts of agricultural drought

Answer 13

-poor yields from rain-fed crops
-irrigation systems start to fail
-pasture and livestock productivity declines
-rural industries affected
-some government aid required

Question 14

what are the major impacts of famine drought

Answer 14

-widespread failure of agricultural systems
-food shortages on seasonal scale
-rural economy collapses
-rural-urban migration
-increased malnutrition and related morality
-humanitarian crisis
-international aid required

Question 15

what are the physical causes of meteorological drought

Answer 15

-Natural variations in atmospheric condition
-El nino

Question 16

what are the physical causes of agricultural drought

Answer 16

-reduction ppt and increased evaporation

Question 17

what are the physical causes of hydrological drought

Answer 17

-reduction in ppt and increased evaporation

Question 18

what are the human causes of meteorological drought

Answer 18

-deforestation
-global warming

Question 19

what are the human causes of agricultural drought

Answer 19

-overgrazing

Question 20

what are the human causes of hydrological drought

Answer 20

-diversion of water for irrigation or dams
-over abstraction of rivers, lakes and aquifers

Question 21

what are el nino and la nina

Answer 21

El Niño and La Niña are changes in this circulation, linked with changes in atmospheric processes

Question 22

what does a normal year look like compared to an el nino year

Answer 22

Strong trade winds
Pushes water to australia (warm)
Upwelling of cold water towards south america
Upwelling is important for fish stocks in Peru

Question 23

what does an el nino year look like

Answer 23

Weak trade winds
It goes the other way pushing warm water to south america
Warm water over whole pacific ocean
The normal east to west trade winds over pacific are disrupted and warm water goes eastwards
No upwelling on South American coast (affects fishing industry)
Air pressure over West coast of S. America becomes low and air over west Australia high pressure

Question 24

what does an la nina year look like

Answer 24

Exaggerated normal
Very strong trade winds
Pushes large amounts of warm water to Australia (west)
As warm water is pushed westwards sea levels rise by up to 1m around Indonesia and Philippines. Strong uplift of air leads to heavy rain!
Air pressure is unusually high over the west coast of S.America and low over eastern Australia
A La Niña episode may, but does not always, follow an El Niño event

Question 25

define positive feedback

Answer 25

a cyclical sequence of events that amplifies or increases changes

Question 26

define negative feedback

Answer 26

a cyclical sequence of events that damps down or neutralises the effect of a system

Question 27

define tipping point

Answer 27

when a system changes from one state to another

Question 28

define resilience in terms of systems

Answer 28

the ability of a system to ‘bounce back’

Question 29

how does drought affect rainforests

hint: use words like pos feedback, resilient etc

Answer 29

Rainforests recycle half of their rainfall, but the positive feedback loop of deforestation + less rainfall is reducing the ability of the rainforests to regenerate → making the rainforest ecosystem less resilient