Cyclone Remal may make landfall along West Bengal coast on May 26: IMD

Sub: Geography

Sec: Climatology

Tags: Cyclone Remal

Context:

Cyclonic storm “Remal” is expected to escalate into a severe cyclonic storm by May 25.

Details:

The India Meteorological Department (IMD) forecasts it will cross the coast between Sagar Island (West Bengal) and Khepupara (Bangladesh) on May 26 with wind speeds of 110-120 kmph, gusts at 135 kmph.

Some facts about Indian tropical storms:

Climatologically, the North Indian Ocean basin, encompassing the Bay of Bengal and the Arabian Sea, experiences the development of approximately five cyclones each year. Of these, an average of four cyclones develop over the Bay of Bengal, while one typically forms over the Arabian Sea.
Cyclones occurring in the Arabian Sea often achieve higher intensities, posing an increased risk of causing widespread damage.
The North Indian Ocean basin is most susceptible to cyclone development during the pre-monsoon months (April-June) and post-monsoon months (October-December).
Cyclones formed in May and November tend to reach higher intensities compared to storms originating at other times due to favourable ocean conditions.

How are Cyclones Classified

How Storm intensification happens:

Tropical cyclones are fueled by ocean heat in addition to other factors.
Ocean temperatures of 26 degrees Celsius or more, prevailing at depths between 50 metres and 100 metres, are conducive to cyclogenesis, which refers to the processes that lead to the development and strengthening of a cyclone.
Warm oceans contribute to a cyclone’s rapid intensification while at sea.
An oceanographic parameter called the Tropical Cyclone Heat Potential (TCHP) is considered an important factor in cyclone genesis, intensification, and propagation.
The intensification process of tropical cyclones is a complex phenomenon influenced by various favorable atmospheric conditions.
These include boundary layers (the fluid layer adjacent to a bounding surface), wind shear (changes in wind direction and/or speed over a vertical or horizontal distance), convection (the transfer of heat within a fluid), Rossby waves (which occur in rotating fluids), upper ocean circulation, and air-sea interaction.
The interaction of these factors contributes to the development and strengthening of tropical cyclones.

What is the landfall of a cyclone?

Landfall occurs when a tropical cyclone moves from a position over water to coming onto land.
According to the IMD, a tropical cyclone is considered to have made landfall when its centre, or eye, crosses the coast.
The “eye” of a cyclone is a zone of relatively calm weather situated at the center of the storm, characterized by light winds, clear or partly cloudy skies, and reduced precipitation.
Within the eye, winds are gentle and variable, often accompanied by clear or partially cloudy skies.
The size of the eye can vary widely, ranging from a few kilometers to over 50 kilometers in diameter in larger cyclones.
During landfall, the outer bands of the storm may have already reached the coast, bringing strong winds, heavy rain, and storm surge.
Landfall signifies the official moment when the cyclone reaches the land.
It’s important to note that landfall is distinct from a ‘direct hit,’ which occurs when the core of high winds (or eyewall) comes onshore while the center of the storm may remain offshore.
Cyclones lose their intensity once they move over land because of sharp reduction of moisture supply and an increase in surface friction.

Council on Energy, Environment and Water (CEEW):

CEEW is a Not-for-profit Think Tank and policy institution based in New Delhi, India.
CEEW was formed to provide independent research-based insights to policymakers for building a sustainable India.
The Council also has an office in Lucknow, Uttar Pradesh. It has multiple research projects running across 22 Indian states and other parts of the world.
CEEW’s research areas include energy and resource efficiency and security; power sector reforms, industrial decarbonisation, sustainable mobility and cooling, sustainable food systems, climate risks and adaptation, air quality, water resources management, sustainability finance, energy-trade-climate linkages and climate geoengineering governance.
The think-tank advises the Indian government.

The study by CEEW:

A study by the Council on Energy, Environment, and Water (CEEW) notes West Bengal’s high adaptive capacity against cyclones due to Early Warning Systems (EWS) under the National Cyclone Risk Mitigation Project (NCRMP) Phase II.
The high teledensity ratio in West Bengal allows people to receive early warnings via telephone or mobile.
CEEW’s study found eastern coastal districts of India are highly exposed to cyclones and highlighted the importance of strengthening adaptive capacity to reduce losses.

Source: TH