Tropical Storms

Question 1

What is are tropical storms?

Answer 1

Intense low-pressure systems

Question 2

What are the names for tropical storms in different regions?

Answer 2

• Typhoon - South China Sea, western Pacific
• Hurricane - Gulf of Mexico, Caribbean Sea, west coast of Mexico
• Cyclone - Bay of Bengal, Indian Ocean, northern Australia

Question 3

What is the distribution of tropical storms?

Answer 3

In general, tropical storms form at all large bodies of water except for in the South Atlantic. This is due to a strong wind shear in the South Atlantic which causes the storms to break before they can form

Question 4

What are factors influencing the formation of tropical storms?

Answer 4

• Oceans - requires moisture for formation of clouds and precipitation, most be at least 70m deep
• Temperature - sea surface temperatures above 27 needed
• Low wind shear
• Coriolis effect - things turn right in Northern Hemisphere, left in Southern Hemisphere
• Latitude - 5-20 degrees, not at equator as no Coriolis effect

Question 5

How are tropical storms formed?

Answer 5

• Warm, moist air rises quickly forming an area of intense low pressure
• The air rises, condenses rapidly and forms thunderstorms over deep (min 70m), warm (above 27 degrees) oceans
• These thunderstorms intensify due to the warm seas and cluster into one larger storm
• As the storms becomes larger, air moves from higher pressure on the outside of the system to the lower pressure in the middle
• The Coriolis effect takes hold as the storm increases in size causing the system to spin
• Light, high altitude wind shear drives the storms direction
• Becomes a tropical storm when winds reach 74mph at the eye wall

Question 6

By what percentage is the average intensity of tropical storms predicted to increase by by 2100

Answer 6

Up to 10%

Question 7

What are the forms of storm hazard (with examples)?

Answer 7

• High winds (up to 195mph during Haiyan)
• Storm surges (over 5m Haiyan)
• Coastal flooding (destroyed 90% of Tacloban)
• River flooding (71 rivers flooded during Hagibis)
• Landslides (over 300 during Hagibis)

Question 8

How is the intensity of tropical storms measured?

Answer 8

Using the 5 point Saffir-Simpson scale which is based strictly on sustained maximum wind speed

Question 9

Outline the frequency and regularity of tropical storms

Answer 9

• On average, 80 tropical storms per year
• Tend to occur during tropical storm season: peak is Aug-Oct in Northern Hemisphere, Jan-Mar in Southern Hemisphere

Question 10

Outline the prediction of tropical storms

Answer 10

• Every year the NOAA (US National Oceanographic and Atmospheric Administration) releases long-term predictions for the coming season
• Involves data from satellites, weather balloons, ocean buoys, radars
• Includes atmospheric pressure, wind speed/direction, humidity, SST, ocean currents
• Data fed into computer models that simulate the behaviour of the atmosphere and ocean to predict the path and intensity
• However, uncertain as tropical storms can be erratic