Question-1:  What are cyclones? Explain the conditions required for formation of cyclones.

Answer:  Cyclones are storm systems that is associated with a low pressure centre and rain-bearing clouds spiralling towards the areasurrounding the centre. They are formed over tropical oceans between the latitudes of 5-30 degree north-south.

Features

• Cyclones formed in the northern hemisphere rotate in anti-clockwise direction and those in southern hemisphere rotate in clockwise direction.
• They are also known as typhoon in Pacific Ocean, Hurricane in America and Willy Willy in Australia.

Conditions for occurrence

• Ambient temperature
  For tropical cyclone to develop over oceans, surface temperatures should be 26 degree Celsius or more. In absence of such high temperatures, the system does not develop.
• Coriolis force
  It is a motion that caused due to rotation of Earth. The Coriolis force is responsible for the cyclonic wind system to acquire spiral motion.
• Small variations in vertical wind speed
  Vertical wind speed should be uniform across the cyclonic system. This prevents the wind system from dispersing.
• Pre-existing low pressure area
  A low pressure area existing in the region helps in sustenance and develops into a tropical cyclone. It acts as root that give rise to storms.

Tags: GS 1 ( Geography)

By – Raghunandan