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Flashcards in Water EQ2 Deck (15)
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1

define the general term drought

an extended period- season, year, several years- of deficient rainfall relative to the statistical multi-year average for a season

2

define meteorological dought

long term precipitation is lower than normal- effected by atmospheric conditions

3

define agricultural drought

there is not enough soil moisture to allow enough crops to grow. Caused by precipitation shortages, changes in evapotranspiration rates and reduced levels of groundwater

4

define hydrological drought

the amount of surface and subsurface water is deficient. Caused by a lack of precipitation or human overuse of water sources

5

define socio-economic drought

when water demand exceeds water availability. Caused by lack of precipitation or human overuse

6

define what ENSO refers to

El Nino Southern Oscillation, occurs in the Pacific Ocean with global impacts on weather patterns due to teleconnections

7

what is the walker cell?

the circulation of air which causes upper atmospheric air to move eastwards and surface air to move westwards across the Pacific resulting in trade winds

8

What is La Nina?

a phenomena where 'normal' conditions intensify.

Low pressure in the west Pacific becomes lower and high pressure in the east grows higher.

Rainfall increases in south east Asia and drought in south America. Trade winds strengthen.
Usually proceeds or follows El Nino

9

What is El Nino

A reversal of normal conditions occurring roughly every 7 years
Low pressure in the East and high pressure in the West due to warm water shifting Eastward. Heavy rain in south America and drought in south east Asia

10

How can we measure the change between El Nino and La Nina?

The Southern Oscillation index (SOI) measures strength, direction and speed
air pressure in South America - air pressure in Australia
if there is a sudden drop in the resulting number, El Nino is imminent

11

why are rainforests struggling to regenerate

positive feedback loop of deforestation and less rainfall

reduced forest cover also reduces soil water storage and evapotranspiration

12

define a wetland

areas where water covers soil
hydrophytes colonise the area and nutrient rich soil is created

13

what factors effect the characteristics of a wetland

regional variation in
soil
topography
climate
hydrology
water chemistry
vegetations
HUMAN FACTORS

14

why are wetlands important

Trap floodwater and distribute it across the flood plain
protects against coastal erosion and storm surges
habitat/ complex ecosystems
support the carbon cycle

15

what are the main causes of water insecurity

Climare variability
Industrial water pollution
Water contamination from agriculture
Salt water encrouchment
over abstraction