Tropical Storms

Question 1

Distribution of tropical storms

Answer 1

5-20° N/S of equator
Over sea 27°C
60m deep

Question 2

Causes of tropical storms

Answer 2

High sea temp - critical level
Rises rapidly - north hemisphere circulating anticlockwise
Pressure drop - more warm moist air
High wind speed (120km/h = cyclone)

Question 3

CS Cyclone Nargis - SE Myanmar May 2008

From Bay of Bengal

Answer 3

90 000 killed 
Irrawaddy delta 95% homes  
Agriculture land - subsistence farmers 
Malnutrition and maleria 
Ground water contaminated 
75% hospitals 
Rangoon airport (4 days) - no aid

Question 4

Ways to reduce hazard of cyclones

Answer 4

Monitoring - satellites/radar track cyclone
History
Hurricane warnings 24h before (USA)
Education - prepare to avoid
Buildings - strong doors, low value on coast (less damage costs)
Prepare emergency supplies

Question 5

Cyclone impacts MEDC vs LEDC

Answer 5

MEDC:
TV, satellites, warning, more finance, emergency food/water/medicine, trained, education

LEDC:
Poor, no shelter/poor buildings, no supplies, poor medical care

Question 6

Formation of delta

Answer 6

1. Approach sea, less energy/velocity, deposit load
2. Dense/salt sea water - flocculation (bind sand)
3. Heavy sand blocks main channel, distributaries
4. Deposition on banks/mouths
5. Up and out into sea, vegetation (sedges)

Question 7

Conditions for delta

Answer 7

Enough sediment (Himalayas)
Sheltered mouth, no strong currents (Bay of Bengal)
More sediment than current removal

Topset (heavy)
Foreset (medium)
Bottom set (fine)

Question 8

CS Ganges delta Bangladesh - 100 000km2

Answer 8

Rice/maize - 20°C, alluvial soil, water supply
Sundarbans Park SW - jobs
Flat - build
Farm fish shrimps - diet/income

Tropical storms + floods
Homes, water contaminated, no food, disease
July 2004 - 800 dead
Difficult transport (goods)

Question 9

Flood and causes

Answer 9

River overflows banks

Causes: 
Heavy rain 
Saturated ground (surface run off, less infiltration) 
Deposition 
Deforestation (surface run off)

Question 10

Flood prevention

Answer 10

Levees/embankment - increase area
Dams - store excess, prevent sudden flood
Flood barrier
Retention basins - divert water when river is high

Dredge Ganges - deepen channel, more help
Straighten Ganges - increase velocity, water out
Floodwalls DHAKA - on banks
Afforestation Himalayas - more evapotranspiration

Question 11

CS Bangladesh flood - July/September 2004

Answer 11

High spring temp in Himalayas
Heavy May monsoon
Floodplain/delta - 70% less than 1m above sea
Rapid deforestation - soil washed into river

50% Dhaka flood 
800 dead 
Water diseases + malnutrition (1million children) 
36 million homeless 
Communications - aid
Rice crops 

Live in Dhaka:
Flat floodplain, alluvium, fertile (rice paddy)
Farm shrimps
Pollutants washed

Question 12

Drought and causes

Answer 12

Prolonged dry period with less water than needs

Causes: 
Deforestation 
Dams 
Industry/agriculture 
High temp - evapotranspiration 
Less rain

Question 13

Problems of drought

Answer 13

Less biodiversity 
Famine 
Desertification 
Dependency (food aid) 
Refugees 
Bush fires

Question 14

CS SE Australia - since 2002

Melbourne, Goulburn

Answer 14

Climate change - hot and dry
Jan 2006 - New South Wales 28°C
Evapotranspiration

Poverty - Deniliquin wheat farmers migrate
Suicide
Saline tapwater - bottled
Bush fires - homes
Melbourne restrict water (sprinkler fines)
Goulburn Pejar reservoir dry, less livestock