Lage Scale Atmospheric Disturbances (tropical Storms)

Question 1

Reasons for the distribution/location of tropical storms

Answer 1

• Warm ocean temps of 27°C. This is because the temperature evaporation of water from the warm ocean provides energy for the storm.
• Interaction of cold and warm air masses. Tropical storms form between cold and warm air masses. When warm air rises and cold sinks it creates an area of low pressure thus causing tropical storm.
• The Coriolis force that gives a spin to the evolving storm. At the equator the earths spin is so strong it cancels out the force. Thus why tropical storm don’t form at the equator.

Question 2

What are the reasons for the source and direction of movement of hurricanes.

Answer 2

• Warm ocean temp. Needs ocean temps of 26°C to form. The evaporation of water from warm oceans provides energy for the storm. This is why many hurricanes are found in the tropics.
• Depth of warm ocean temperatures. Hurricanes require warm ocean temps to at least 60m of depth. The deeper the warm water, more energy is available.
• Coriolis effect: The Coriolis effect is a force that deflects moving objects to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. It influences the direction in which hurricanes move.

Question 3

Explain the variations in the warning times and hazard durations

Answer 3

• Earthquakes give little warning time. An example is Mount Ontake earthquake which gave 5-7 minutes l warning time. It occurred shortly after and caused 57 deaths
• Hurricanes can be observed forming offshore and moving towards the coast and alarm people. An example is Cyclone Idai which had 3 days of warning before it made landfall in 2019.
• Volcanoes can show warning signs such as seismic activity and gases several weeks before the eruption. An example is Mount Pinatubo which gave about 10 weeks of warning before its eruption.