Drought

Question 1

Meteorological drought

Answer 1

This is a period when there is little or no rainfall

Question 2

Hydrological drought

Answer 2

When water levels in rivers and lakes are low

Question 3

Agricultural drought

Answer 3

When the levels of water in soil are low

Question 4

Famine drought

Answer 4

When drought has impacts on water supply to different users. At this stage certain uses might be prioritised

Question 5

Supply

Answer 5

About the physical availability of water
-strongly linked to physical factors +human supply systems
-poor management of water supplies tends to reduce supply

Question 6

Demand

Answer 6

-How much water is required
-Depends on human factors
-can also be reduced by encouraging conservation and charging a realistic price for water

Question 7

Drought

Answer 7

Abnormally long period of low rainfall
Can be short term (weeks-months) or long term (years-decades)
Drought is measured using a drought index/ rainfall index

Question 8

Global Atmospheric Circulation

Answer 8

Local water budgets/river regimes
Water. Surplus/ deficit areas+seasonality of supply
ENSO cycles
Drought
Major cells, high and low pressure areas +precipitation levels, seasonal movement of the ITCZ and polar fronts

Question 9

Sahel

Answer 9

An addition to the Sahara, intertropical conversion zone hasn’t given enough rain so land has been made into desert

Question 10

Intertropical convergence zone

Answer 10

-appears as a band of clouds with showers and thunderstroms
-encircle the globe near the equator
-northeast trade winds and southeast trade winds converge in a low pressure zone

Question 11

Jet Stream

Answer 11

Polar front and Sub tropical Jet Stream
-core of strong winds around 5 to 7 miles above the earths surface
-blowing from east to west
-flows high overhead
-causes changes in the wind ad pressure at that level
-affects areas of high and low pressure

Question 12

Teleconnections

Answer 12

Changes in the atmosphere in one place can affect weather over 1000 miles away.

Question 13

Teleconnection patterns

Answer 13

Caused by changes in the way air moves around the atmosphere
Natural occurrence

Question 14

El Niño

Answer 14

Major teleconnection pattern created by El Nino Southern Oscillation (ENSO) changes to the atmosphere and ocean
-cold and dry air is blown into places that typically have warm and moist air
-changes in the temperature of the ocean surface in the tropical Pacific Ocean also affect the weather
-9-24 months is that duration of El Niño

Question 15

Meteorological causes of drought

Answer 15

-persistent high-pressure; related to the jet stream
-seasonal rain/ monsoon failure: linked to the ICTZ (inter tropical convergence zone)
-ENSO cycles changing distribution of pressure belts
-long term precipitation changes caused by global warming

Question 16

Teleconnections

Answer 16

Climate anomalies which relate to each other at large distances

Question 17

Human influences on drought

Answer 17

-deforestation
-overgrazing
-polluting water supplies
-over-abstraction of reservoirs, rivers and aquifers
-building dams
-changing land use
-increasing populations

Question 18

Aquifer

Answer 18

A permeable or porous rock which stores water

Question 19

Humus

Answer 19

Black belly like substance that sticks soil particles together

Question 20

Desertification

Answer 20

When good viable land is turned into a desert

Question 21

Physical causes of flooding

Answer 21

-relief
-drainage density
-natural disasters
-previous weather conditions
-snowmelt
-rock type
-vegetation
-amount and type of rain