weather gateway 3 Flashcards
Characteristics of tropical cyclones
Sustained wind speeds of 119 km/h → atmospheric pressure above warm oceanic surface is very low → steep pressure gradient → strong winds spiralling inwards and upwards at high speeds → sinking column of air in the centre known as ‘the eye’
Low pressure at the centre → warm moist air over the ocean expands and rises → condensation occur → releases latent heat (heat energy from formation of water droplets) → warms surrounding air → expand and rise further
conditions required for tropical cyclones form
between latitude of 8° and 15° north and south of the equator
High ocean temperatures above 26.5°C° → heat and moisture from the ocean waters are required for the tropical cyclones to form. → cannot sustain energy and will dissipate on cool waters/land
Coriolis effect
Hazards of tropical cyclone: Storm surges
D- A sudden rise in sea level in which water is piled up against a coastline beyond normal conditions on high tide due to huge waves caused by a cyclone
Ex- 2008 hurricane Ike caused a storm surge of 4-6 meters above normal tide lvl in texas, causing an estimated property damage of US$2, billion
A- Massive flooding can cause high death tolls and property damage
Hazards of tropical cyclone: Strong winds
D- Strong winds that accompany tropical cyclones may cause loose flying debris
Ex- 1992 hurricane Andrew → strong wind speeds 177km/h → widespread damage to bahamas and various parts of the US
A : causes damage to property and injure people
Hazards of tropical cyclone: Torrential rain
D- tropical cyclones produce large amount of rain that can cause inland flooding and destabilise slopes
Ex- 2004 Hurricane isabel → flooded rivers in the USA → damage of more than $2.2 billion
A- May damage buildings or lead to high death tolls
Impacts of cyclones: Physical impacts
D- damage to infrastructure such as buildings, bridges and roads
Ex- 2009 Typhoon Ketsuna → destroyed 80% of health centres in Manila, capital city of phillippines → extremely difficult to distribute food and medicine
A- when bridges and roads are destroyed → it may be difficult to transport food, clean water and medicine to areas in need
Impacts of cyclones: Economic impact
D- Cost of repairs of damaged property and infrastructure as well as loss of income due to damaged crops
Ex- cyclone Yasi, 2011, North queensland Australia → 75% of the banana crops amounting to $350 million was lost
A- property and infrastructure may be expensive to repair, food shortages may occur due to destroyed food and farmlands
Impacts of cyclones: Social
D- disruption to the water supply and sanitation/hygiene facilities which can contaminate water
Ex- 2009, Hurricane Aila in west bengal, india → contaminated water caused a cholera outbreak resulting in about 1000 infected people and 14 deaths
A- contaminated water and poor hygiene facilities can lead to an outbreak of diseases which may lead to an increased death toll
Cyclone emergency response (DExAL)
D- Immediate action in response to any situation that poses risk to people’s health and lives
Ex- Community cyclone shelter in bangladesh → used by governments to evacuate people → built w strong concrete which are raised above ground to be able to withstand the hazards associated with tropical cyclones.
A- Greatly reduced the no of casualties in Bangladesh and India.
L- Assistance from the national government and governments of neighbouring countries → repair damage and provide aid
Cyclone mitigation measures: Prediction and Warning
D- mitigation measures are strategies taken to reduce or avoid the impact of a hazard
D- prediction and warning refers to analysing long term climate records to determine patterns of the occurrences and severity of damage caused by past cyclones
Ex- in Japan, warning systems for cyclones were installed so when the approach of tropical cyclones is predicted, people can be warned and evacuated in time
A: Able to predict when cyclones of of a similar severity would occur, thus allowing people to be warned and evacuated in time
L: climate records of past events only indicate the frequency of tropical cyclones and do not give accurate details about when future tropical cyclones will occur
Cyclone mitigation measures: Land use control (coastal plain management) DExAL
D- regulating land use on coastal areas by placing restrictions on how land can be used such as implementing higher taxes or protected zones
Ex- Coastal plane management is used in Queensland Australia to prevent damage to infrasturcture
A- No developments are effected if the are becomes flooded or a cliff collapses
L- Successful only when authorities are able to enforce them →requires time and manpower.
residents may be reluctant to move out → government needs to purchase land →very costly
Cyclone mitigation measures: Land use control (Floodplain management) DExAL
D- Floodplain management refers to the management of low lying areas near rivers or coasts to prevent floods and facilitate evacuation.
Ex- Cairns, Australia → made floodplain management plan based of models of storm surge floods to facilitate evacuation
A- people are able to leave a flooded area as quickly as possible
L-Only based on past occurrences of storm surge floods and may not be completely accurate
Cyclone mitigation measures:Reducing vulnerability of infrastructure (DExAL
D- ensuring infrastructure is able to withstand tropical cyclones, includes designing buildings that are resistant to wind and water damage and regular inspection of river embankments
Ex- Florida, United States of America, the state government aids homeowners by employing specialised companies to improve the design of the roof and the openings of the houses. Allowing for cit
