1-A Weather Hazards Flashcards
What is required for a tropical storm to occur?
- Sea temperature > 27*C (most common times of this are between Summer and Autumn)
- Sea depth of 60 - 70 m
(Two previous points provide heat and moisture that causes warm air to rise rapidly in low-pressure region) - Low wind shear (constant and doesn’t vary in height) so tropical storm clouds can rise to high levels without being torn apart
- Doesn’t develop along Equator, Coriolis Effect is not strong enough here for tropical storms to spin
Where do tropical storms broadly occur and why?
They occur broadly south of the Tropic of Cancer and north of the Tropic of Capricon. Why? Because there is higher insolation meaning temperatures are higher than at poles
How do tropical storms form and develop?
1) Air heated above surface of warm tropical oceans. Warm air rises rapidly under low-pressure conditions
2) Rising air draws up more air and moisture from ocean, causing strong winds
3) Coriolis Effect spins wind around calm central eye of storm
4) Air rises, it cools and condenses -> Forms large, towering Cumulonimbus clouds, generates torrential rainfall. Heat given off when air cools powers tropical storm
5) Cold air sinks in eye, so no cloud, so its drier and much calmer
6) Tropical storms travel along ocean in prevailing winds
7) Tropical storm meets land, loses power from moisture and heat from Ocean so weakens and changes direction
How does climate change generally impact tropical storms?
- Temperature increases -> Sea levels rise due to thermal expansion (meaning storm surges are expected to become higher)
- Warmer atmosphere = air can hold more moisture -> Heavy rainfall to increase (flooding during a tropical storm will be more destructive)
How does climate change impact the intensity of tropical storms?
- There is evidence for link between warmer oceans and the intensity
- Become 2-11% more destructive by 2100
- Numbers of most severe category 4/5 increased since 1970s
- Predictions say every 1*C increase in tropical sea surface temperature = 3-5% increase in wind speed
How does climate change impact the frequency of tropical storms?
- Stay the same or decrease because of climate change
- BUT, category 4-5 will increase and 1-3 will decrease
How does climate change impact the distribution of tropical storms?
- Climate change won’t impact the distribution significantly
What will be impacted by a tropical storm?
The effects of a tropical storm will impact the people and the environment.
What will be the impact in a tropical storm?
- Strong winds
- Torrential rain
- Storm surges (sea levels rise rapidly high due to storm)
- Landslides
- Tornadoes
What are the primary effects of a tropical storm?
- Wind speeds of 119 km/h can demolish houses across whole towns and villages, destroy infrastructure and crops
- Storm’s destruction depends on strength and how well people and property are protected
What are the secondary effects of a tropical storm?
- Flooding caused by heavy rain and storm surges (wind pushing seawater onto coastline - can be 5m tall)
- Heavy rainfall (500 ml in 24 hrs) - most cause of death is due to flooding
- Aid is hampered because roads are flooded
- Torrential rain can trigger land slides
- Water supplies can be contaminated with sea water, sewage and industrial waste - risk of waterborne diseases
What are the immediate responses to a tropical storm?
- Evacuation for predicted tropical storms to higher grounds or to emergency storm shelters (tropical storms can be generally predicted)
What are the long-term responses to a tropical storm?
- Shelter provided by public buildings or tents provided by international aid are necessary when homes are damaged
- Distributing emergency food and water - HICs have resources to do (large scale disasters international aid is required though)
- Aid may be hindered if roads are blocked or flooded. Take longer for aid to reach remote areas
- Governments, NGOs and charities aim for sustainable development after initial relief effort has saved lives
How can monitoring reduce the effects of tropical storms?
- Monitoring allows prediction = can save lives and reduce damage
Satellites:
- Satellites monitor cloud pattern associated with tropical storms
- Global Precipitation measurement satellite monitor precipitation every 3 hours between latitudes 65* north and south of equator
Aircraft:
- Specially equipped aircraft fly through tropical storm at 10,000 feet to collect air pressure, rainfall and wind speed data
- NASA monitor weather patterns across Atlantic with two unmanned aircraft called Global Hawk drones.
How can predicting reduce the effects of tropical storms?
- Available weather data fed into supercomputers which run predictions which predict the path and intensity of tropical storms
- 2013, National oceanic and Atmospheric Administration (NOAA) made supercomputer which can give 5 days warning and accurate location within 400 km
- 2013, Cyclone Phailin in India was successfully predicted. 1.2 million people were evacuated. 21 people died. BUT, 1999, similar cyclone hit same area and killed more than 10,000 people
