What is a Cyclone?
Any significant wind storm that revolves around a low-pressure center in a counterclockwise motion to the north of the Equator and a clockwise manner to the south is called a cyclone. Except for the equatorial belt, cyclonic winds travel almost the whole planet and are typically linked to precipitation or snowfall. Anticyclones are a type of wind pattern that revolves around a center of high pressure and also occurs in similar places. Anticyclones get their name because their flow is the reverse of a cyclone’s, meaning that they spiral outward while the winds in the Northern Hemisphere rotate clockwise and in the Southern Hemisphere counterclockwise. These winds typically don’t create precipitation and aren’t as intense as the cyclonic version.
Cyclones in Different Hemispheres
The middle and high latitude belts in both hemispheres are the primary locations for cyclones. Cyclones are dispersed quite uniformly across a range of longitudes in the Southern Hemisphere, where the oceans cover the majority of the land area. They typically originate in latitudes between 30° and 40° S, migrate mostly southeast, and mature at latitudes of about 60°. In the Northern Hemisphere, things are dissimilar.
There, huge mountain belts interfere with the midlatitude air currents, causing notable changes in the frequency of cyclones (and anticyclones). Continental landmasses stretch from the Equator to the Arctic. The wind systems favor certain tracks over others. The main cyclone paths are across the oceans and frequently cross continental coasts and mountain barriers to the east.
Tropical and Extratropical Cyclones
Tropical cyclones and extratropical cyclones, often known as temperate cyclones, are the two categories of cyclones.
When winds surpass “Gale Force,” which is defined as a minimum of 34 knots or 63 kph, a weather system is referred to as a “Tropical Cyclone” by the World Meteorological Organization (WMO, 1976). The offspring of the ocean and atmosphere, tropical cyclones are propelled by the heat from the sea, strong planetary winds, temperate westerlies, easterly trades, and their intense activity.
Cyclones in India are categorized by:
Wind speed and storm surge intensity are unusually high rainfall events.
Even though they are known to begin in Polar locations, extratropical cyclones are known to arise in temperate zones and high-latitude locations.
Tropical cyclones are storms that form in the areas between the Tropics of Cancer and Capricorn. Large-scale weather systems by the name of tropical cyclones form over tropical or subtropical waters, where they flock together into surface wind circulation.
Terminology used globally
In different parts of the world, cyclones are referred to by different names. In the China Sea and Pacific Ocean, they are called typhoons; in the Caribbean Sea and Atlantic Ocean, they are called hurricanes; in the Guinea lands of West Africa and the southern United States, they are called tornadoes; in northwestern Australia, they are called willy-willies; and in the Indian Ocean, they are called tropical cyclones.
The Formation of Tropical Cyclones
Tropic cyclone initiation can be categorized into three phases:
Formation and First Phase of Development
A cyclonic storm’s origin and early evolution are dependent on several points. These are the following:
A warm sea (beyond 26 degrees Celsius down to 60 meters deep) with an enormous and stormy evaporation of water vapor into the surrounding sky. Due to convection and the condensation of rising air above the ocean’s surface, atmospheric variability aids the production of huge vertical cumulus clouds.
Developed Tropical Cyclones
The air rises in strong thunderstorms during an amplifying tropical cyclone and tries to spread out horizontally at the tropopause level. As the air spreads, unusual amounts of positive perturbation pressure are created, which speeds up the air’s convectional descent. A heated “Eye” is produced when subsidence is induced, warming the air through compression. Three primary geometries are typically seen in the “Eye” of a storm: (i) circular; (ii) concentric; and (iii) elliptical. A mature tropical cyclone in the Indian Ocean is characterized primarily by a concentric pattern of extremely turbulent huge cumulus thundercloud bands.
Change and The breakdown As soon as a tropical cyclone’s intake of warm, moist air starts to diminish or is suddenly cut off, it loses strength in terms of its center low pressure, internal warmth, and extremely fast speeds. This comes as it crosses across chilly waters or after it touches down on land. A cyclone’s weakening does not indicate that there is no longer a risk to people or property.
Cyclone Vulnerability in the Indian Subcontinent
Among the worst-hit areas in the world is the Indian subcontinent. With an 8041-kilometer-long coastline, the subcontinent is vulnerable to around 10% of all tropical cyclones that occur worldwide. Most of these originate over the Bay of Bengal and strike the east coast of India. Five to six tropical cyclones form a year on average, with two or three of them having the potential to be severe. The Bay of Bengal has roughly a 4:1 ratio of more cyclones than the Arabian Sea. On both coasts—the east coast’s Bay of Bengal and the west coast’s Arabian Sea—cyclones are common.
Nearly 262 cyclones (92 of which were severe) occurred in a 50 km wide strip over the East coast of India between 1891 and 1990, according to an analysis of the frequency of cyclones on the East and West coasts of the country. On the West Coast, where 33 cyclones—19 of which were strong—occurred during the same time, there has been less severe cyclonic activity.
Seasonal Patterns of Cyclones in the Indian Ocean
May–June and October–November are the months when tropical cyclones occur. In the North Indian Ocean, cyclones with severe power and frequency have a bi-modal pattern, with a primary peak in November and a secondary peak in May. On account of the devastating wind, storm surges, and heavy rains that precede landfall in the North Indian Ocean (the Bay of Bengal and the Arabian Sea), there is an increased risk of tragedy. Storm surges are the most deadly of these because they overpower low-lying coastal areas, causing catastrophic flooding, eroding beaches and embankments, destroying vegetation, and lowering soil fertility.
The Devastating Effects of Cyclones
Although cyclones range in diameter from 50 to 320 km, thousands of square kilometers of the ocean’s surface and the lower atmosphere are affected by them. The powerhouse is positioned within a 100-kilometer radius, even though the boundary is 1,000 kilometers long. Given that winds up to 320 km/h may strike closer to the Eye.
Because of the unusual amount of rainfall and storm surge inundation in inland areas, tropical cyclones, which are characterized by destructive winds, heavy rainfall, and storm surges, break off regular life and cause floods as a result. The destructive power of cyclones to destroy buildings, including homes, hospitals, food storage facilities, critical infrastructure like power and communication towers, highways, bridges, and culverts, as well as crops, is what makes them so dangerous.