W & C GW3 Flashcards
Characteristics of tropical cyclones
1. ?
Strong Winds
strong winds of at least 119km/h
low atm pressure above warm oceanic surface in centre of cyclone -> steep pressure gradient -> strong winds moving inwards and upwards at high speeds -> column of sinking air = eye
Characteristics of tropical cyclones
2. ?
Low Central Pressure -> eye
moist air over ocean expands and rises -> condensation -> releases latent heat = heat energy released when waer vapour condenses into water droplets
continuous and large scale release of latent heat warms air, cauding air to expand and rise further -> reduces air pressure near ocean surface -> creating and sustainging area of low pressure in centre
air cools and sinks -> descending air creates environemnt at centre -> calmness and absense of clouds -> eye
Where are tropical cyclones found?
- (1)
- (2)
- Between latitudes of 8° and 15° north and south of Equator
- Conditions
High ocean surface temp above 26.5°C
Coriolis effect
Where are tropical cyclones found?
Conditions
1. ?
High ocean surface temp above 26.5°C
heat and moisture from ocean water needed to form -> sustain energy
Where are tropical cyclones found?
Conditions
2) ?
Coriolis Effect
Northern hemisphere -> deflects winds to right -> acw
Southern hemisphere -> deflect winds to left -> cw
Hazards associated with tropical cyclones
3
- Storm surges
- Strong Winds
- Torrential rainfall
Hazards associated with tropical cyclones
1. ?
P: Storm Surges
E: low air pressure and strong winds -> tropical cyclones form over warm ocean water -> intense low pressure in eye cause sea level to rise -> strong winds -> huge waves -> sudden rise of sea level, pile up against coastline beyond normal high tide
E: In Texas 2008, Hurricane lke caused a storm surge of 4-6 metres above normal tide -> property damage US$24.9 billion
Hazards associated with tropical cyclones
2. ?
P: Strong Winds
E: strong winds -> loose debris to fly and hit people and buildings -> damage infrastructure, injure people
E: Hurricane Andrew in 1992, strong winds up to 177km/h -> damage to Bahamas and various parts of US -> disrupted power supply of 150 000 homes
Hazards associated with tropical cyclones
3. ?
P: Torrential rain
Ex 1: large amounts of rainfall -> inland flooding, overflow rivers and streams
Eg 1: Hurricane Isabel 2003 flooded rivers -> flood Virginia, Washington DC -> area about 120 times of SG -> damage of more than US$2.23 billion
Ex 2: rainfall -> too much water in soil -> soil unstable -> landslide -> remove and crush buildings
Impacts of tropical cyclones
3
- Physical
- Economic
- Social
Impacts of tropical cyclones
1. ?
P: Physical impact
E: damage to infrastructure (buildings, bridges, roads) -> difficult to transport food, clean water, medicine to areas that need these items, communication networks also disrupted
E: Typhoon Ketsuna in 2009 -> damage road network in Philippines, Cambodia and Laos -> hindered rescue work -> 80% of healthcare centres in Manila, Philipines destroyed -> difficult to distribute food and medicine
Impacts of tropical cyclones
2. ?
P: Economic Impact
Ex 1: costs of repair of damaged property and infrastructure
Eg 1: damage caused by Hurricane Katrina in 2005 cost US$81 billion, large portion of cost came from repairs of more than 200,000 homes
Ex 2: damaged crops -> loss of income
Eg 2: Tropical Cyclone Yasi in Northern Queensland, Australia in 2011, 75% of banana crops that cost about US$350 million was lost
20% of area of sugarcane farmland destroyed, farmers suffering economic losses
Ex 3: Food aid needs to be provided to victims as crops are destroyed -> however, flooded roads make it difficult to let people from affected areas to access to food aid -> $$ needed to repair roads to provide aid
Eg 3: Cyclone Nargia 2008 in Myanmar, US$4 billion needed to repair infrastructure and to provide humanitarian aid
Impacts of tropical cyclones
3. ?
P: Social impacts
P 1: disruption to water supply, sanitation, hygiene facilities, water-borne diseases
Ex 1: flooding -> sewage from burst sewage pipes to flow into existing water supplies -> contaminate them -> spread of water-borne diseases (cholera, typhoid fever)
Eg 1: Cyclone Aila 2009 in West Bengal India, contaminated drinking water -> cholera outbreak 1000 infected people and 14 deaths
P 2: spread of diseases
Ex 2: flooding -> stagnant water -> increase spread of diseases
Eg 2: Hurricane Mitch in 1998 increases dengue fever and malaria cases in Guatemala and Nicaragua -> large-scale flood, diseases spread at fast rate -> difficult to provide proper medical care
P 3: displacement of people from their homes
Ex 3: houses destroyed during hurricane -> lost homes, no place to stay
Eg 3: Hurricane Katrina in 2005 in New Orleans, US, hundreds of thousands of people lost their homes -> victims lived in temporary shelters
How ppl respond to tropical cyclones?
- (3)
- Emergency action
2. Mitigation measures (3)
How ppl respond to tropical cyclones?
1. ?
Emergency action
- involves taking immediate action in response to nay situation that poses risk to people’s health and lives
- protect lives and properties
- national government: repair damage
- non-governmental organisations: provide basic necessities
Eg) Red Cross is a non-governmental organisation provide victims with basic necessities such as food, clothing, shelter and healthcare when Typhoon Megi hit the Philippines in 2010
