Why in News
Hyderabad based Indian National Centre for Ocean Information Services (INCOIS) alerted the coastal States of Goa, Maharashtra, West Bengal, Odisha, Tamil Nadu, Kerala, Lakshadweep and Andaman & Nicobar Islands, of the possibility of high-energy swell waves over the weekend
It also urged total suspension of operational/recreational activities at beach/nearshore regions
Coastal communities in Kerala were advised to remain vigilant with State being put on red alert for high-energy swell waves.
The phenomenon, known locally as ‘Kallakadal’
Swell waves
A swell, also sometimes referred to as ground swell, in the context of an ocean, sea or lake, is a series of mechanical waves that propagate along the interface between water and air under the predominating influence of gravity, and thus are often referred to as surface gravity waves.
These surface gravity waves have their origin as wind waves, but are the consequence of dispersion of wind waves from distant weather systems, where wind blows for a duration of time over a fetch of water, and these waves move out from the source area at speeds that are a function of wave period and length.
Formation:
They occur not due to the local winds, but rather due to distant storms like hurricanes, or even long periods of fierce gale winds.
During such storms, huge energy transfer takes place from the air into the water, leading to the formation of very high waves.
Such waves can travel thousands of kilometres from the storm centre until they strike shore.
Swell waves often have a relatively long wavelength, as short wavelength waves carry less energy and dissipate faster, but this varies due to the size, strength, and duration of the weather system responsible for the swell and the size of the water body, and varies from event to event, and from the same event, over time
Swells have a narrower range of frequencies and directions than locally generated wind waves, because swell waves have dispersed from their generation area, have dissipated and therefore lost an amount of randomness, taking on a more defined shape and direction.
These waves can propagate in directions that differ from the direction of the wind, in contrast to a wind sea.
Their wavelengths may rarely exceed more than 150 m.
Swell wavelength, also, varies from event to event.
Occasionally, swells which are longer than 700 m occur as a result of the most severe storms.
It occurs without precursors or any kind of local wind activity and as a result.
Impacts
Surfing: Swells are essential for surfing, providing the consistent, large waves sought after by surfers.
The quality of surf breaks is significantly influenced by the characteristics of incoming swells, such as their direction, period, and size.
Coastal Erosion: Swell waves can contribute to coastal erosion, especially during storms when their energy is amplified.
Navigation and Safety: For maritime navigation, understanding swells is crucial for the safety and efficiency of shipping and small craft operations.
Energy Generation: Swell waves are a focus of research for renewable energy generation, where their consistent nature could be harnessed to produce electricity.
INCOIS
Indian National Centre for Ocean Information Services (INCOIS) is an autonomous organization under the Ministry of Earth Sciences (MoES)
It is located in Hyderabad & was established in 1999.
It is a unit of the Earth System Science Organization (ESSO), New Delhi.
It is mandated to provide the best possible ocean information and advisory services to society, industry, government agencies and the scientific community through sustained ocean observations and constant improvement through systematic and focused research.
Services provided
Provides round-the-clock monitoring and warning services for the coastal population on tsunamis, storm surges, high waves, etc. through the in-house Indian Tsunami Early Warning Centre (ITEWC).
Provides daily advisories to fisher folk to help them easily locate areas of abundant fish in the ocean while saving on both fuel and time used to search for the same.
Short-term (3-7 days) Ocean State Forecasts (waves, currents, sea surface temperature, etc.) are issued daily to fisher folk, the shipping industry, the oil and natural gas industry, the Navy, the Coast Guard, etc.
Deploys and maintains a suite of Ocean Observing Systems in the Indian Ocean to collect data on various oceanic parameters.
Conducts systematic quality checks and archives all observational, satellite, and other oceanic data at the ESSO-INCOIS Data Centre, and then makes such data available to students, researchers, and any other users.
INCOIS has been designated as the National Oceanographic Data Centre by the International Oceanographic Data Exchange Programme (IODE) of the IOC.
Generates Global Ocean Analysis data using mathematical models and observations on a daily basis to provide the initial conditions to ocean-atmosphere coupled models used for the prediction of the monsoon and to understand oceanic processes.
Established a national network (Indian Seismic and GNSS Network (ISGN)) that integrates Seismic and GNSS stations and provides high quality data for research and operational use.
It serves as the National Argo Data Centre, Regional Argo Data Centre, and also the regional data centre and clearing house for the Indian Ocean region for the Indian Ocean Global Ocean Observing System (IOGOOS) Programme.
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