Physical Geography Mock

1. What is a tropical storm? Tropical storms are a large, spiralling area of low pressure formed in tropical waters (26), with winds of 39mph or over, and for a tropical cyclone, 74mph or over. 

With the exception of the hurricanes that affect the west coast of Mexico, tropical cyclones affect the east coasts of continents and are most hazardous to the Carribean and the densely-populated, low-lying coasts of Bangladesh, the Bay of Bengal and south-east USA. 

Differing names for tropical cyclones:

> Hurricanes > Carribean Sea, Gulf of Mexico, west coast of Mexico 

> Cyclones > Indian Ocean, Bay of Bengal, northern Australia 

> Typhoons > south China Sea, west Pacific Ocean. 

• Tropical cyclones form over warm oceans between May and November in the northern hemisphere and between November and May in the southern hemisphere. 
  • Tropical storms form only between 5o-20o north snd south-they don't form nearer the Equator since the Coriolis force is needed to deflect the converging rising air into a spin (and this force is weaker nearer to the Eq). 
  • Whilst they cannot form in higher latitudes since the sea's night warm enough for their formation. 

• Sea temperatures have to be a minimum of 26oC to a depth of at least 50m. 

• They form in the sumer (when the noonday sun is high in the sky), with maximum occurence in late summer and autumn after a long period of intense heating. 
  • The warm sea is important, with it warming the air in contact with it so that the water vapour can evaporate into the air that moves the storm. 
    • This moisture fuels the growth of the storm, which can only happen if the air is unstable (warmer than the air at the sam heigh), so it will continue to rise. > The heated, moist aur expands, becomes light and rises. 

Understand the ways in which large scale tropical disturbances:

• originate 

• develop (or not) and the role of latent heat
  • The process involved in the tropical cyclone intensify whilst it remains over warm water as the rising air rcools to below dew point, causing condensation to release latent heat resulting in the air to rise even faster, the low pressure to lower even more and the moisture laden-wind to rush into the low pressure centre even faster. The lower the pressure the more the air is drawn into it, and the greater the power.

• have particular directions
  • the effect of the Coriolis force can be seen in the directionof movement of the tropical storms, as they generally deflect to the right in the northern hemisphere and to the left in the southern hemisphere.
  • (Unless very strong winds exceed the Coriolis force and change the direction of the rotation. 

• quickly 'die' over land 
  • They gradually reduce in intensity over cooler seas and so reapidly land where they lose their source of energy-water vapour intake. 

• Houses destroyed, deaths (e.g. through being drowned) and injuries. 
• Flooding, pollution (sewage, drains), disease, hunger, fires (power lines down), disruption of transport. 
• Aid: reliance, bad distribution due to damaged infrastructure. 
• Social unrest: looting, tension.. 
• Agriculture-crops lost, pollution and particular damage to tree crops. 
• Long term economic impacts, cost, destruction of infrastructure, loss of jobs...
• Trade, loss of exports, reliance on imports. 

·     describe how large-scale atmospheric disturbances can be predicted mapped, prepared for and monitored and to what level of success consider different perceptions of risk by people in varied world locations