⦿ Cyclones developed in the regions lying between the tropics of Capricorn and Cancer are called tropical cyclones which are not regular and uniform like extratropical or temperate cyclones.
⦿ Size of tropical cyclones varies consider- ably. On an average, their diameters range between 8Okm and 300ķm but some times they become so Small that their diameter is restricted to 50km or even less.
⦿ They advance with varying velocities. Weak cyclones move at the speed of about 32km per hour while hurricanes attain the velocity of 180km per hour or more.
⦿ Tropical cyclones become more vigorous and move with very high velocity over the oceans but become weak and feeble while moving over land areas and ultimately die out after reaching the inte- rior portion of the continents
⦿ This is why these cyclones affect only the coastal areas of the çonti- nents (e.g. south and south-east coasts of the USA, Tamil Nadu, Orissa and West Bengàl coasts of India, southern coastal regions of Bangladesh etc.).
⦿ The centre of the cyclone is characterized by extremely low pressure.
⦿ Isobars are more or less circular but are fewer in number.
⦿ Like temperate cyclones, tropical cyclones, are not characterized by temperature variations in their different parts because they do not have different fronts (warm and cold fronts).
⦿ There are no different rainfall cells in the tropical cyclones as is the case of temperate cyclones and hence each part of the cyclones yields rainfall.
⦿ Tropical cyclones are not always mobile. Some times, they become stationary over a particu- lar place for several days and yield heavy rainfall causing fiood deluge and environmental disaster.
⦿ The tracks of tropical cyclones vary con- siderably in different parts. Normally, they move from east to west under the influence of trade winds.
⦿ The general direction is westerly upto 15° Latitude from the equator, poleward between 15-30 latitudes.