Source: Times of India
Context:
Cyclone Biparjoy in the Arabian Sea intensified into a ‘very severe cyclone’. Currently located about 850 km west of Goa, it is expected to move northwards and turn towards Oman in the coming days. While this will help the monsoon onset in Kerala.
Cyclone Biparjoy
A deep depression over the southeast Arabian Sea intensified into a cyclonic storm ‘Biparjoy’, said the India Meteorological Department (IMD)
The name ‘Biparjoy’ was given by Bangladesh. It means ‘calamity’ or ‘disaster’. Reportedly, the name was adopted by World Meteorological Organisation (WMO) countries in 2020.
It also includes all the tropical cyclones that form over the North Indian Ocean, including the Bay of Bengal and the Arabian Sea as cyclones are named depending on the regional rules.
What are Tropical Cyclones?
The Tropical Cyclones are violent storms that originate over oceans in tropical areas and move over to coastal areas bringing about large-scale destruction caused by violent winds, very heavy rainfall and storm surges.
These are low pressure weather systems in which winds equal or exceed speeds of 62kmph.
Winds circulate around in anti-clockwise direction in the Northern Hemisphere and in clockwise direction in the Southern Hemisphere.
“Tropical” refers to the geographical origin of these systems, which form almost exclusively over tropical seas.
“Cyclone” refers to their winds moving in a circle, whirling round their central clear eye, with their winds blowing counter clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.
The opposite direction of circulation is due to the Coriolis effect.
Tropical Cyclones in India
Tropical cyclones striking India generally originate in the eastern side of India.
Bay of Bengal is more prone to cyclone than Arabian Sea because it gets high sea surface temperature, low vertical shear winds and has enough moisture in middle layers of its atmosphere.
The frequency of cyclones in this region is bi-modal, i.e., Cyclones occur in the months of May–June and October–November.
Conditions for cyclone formation:
A warm sea surface (temperature in excess of 26o –27o C) and associated warming extending up to a depth of 60m with abundant water vapour.
High relative humidity in the atmosphere up to a height of about 5,000 metres.
Atmospheric instability that encourages the formation of cumulus clouds.
Low vertical wind between the lower and higher levels of the atmosphere that do not allow the heat generated and released by the clouds to get transported from the area.
The presence of cyclonic vorticity (rate of rotation of air) that initiates and favours rotation of the air cyclonically.
Location over the ocean, at least 4–5 o latitude away from the equator.
Names of Tropical Cyclones
Depending on its location and strength, a tropical cyclone is referred to by different names:
- Cyclones in the Indian Ocean
- Hurricanes in the Atlantic
- Typhoons in the Western Pacific and the South China Sea
- Willy-willies in Western Australia
Landfall, what happens when a Cyclone reaches land from the ocean?
Tropical cyclones dissipate when they can no longer extract sufficient energy from warm ocean water.
A storm that moves over land will abruptly lose its fuel source and quickly lose intensity.
A tropical cyclone can contribute to its own demise by stirring up deeper, cooler ocean waters. tropical cyclone can contribute to its own demise by stirring up deeper, cooler ocean waters.
Cyclone Management in India
India is highly vulnerable to natural disasters especially cyclones, earthquakes, floods, landslides, and drought. Natural disasters cause a loss of 2% of GDP every year in India. According to the Home ministry, 8% of total area in India is prone to cyclones. India has a coastline of 7,516 km, of which 5,700 km are prone to cyclones of various degrees.
Loss due to cyclones: Loss of lives, livelihood opportunities, damage to public and private property and severe damage to infrastructure are the resultant consequences, which can disrupt the process of development
Indian Meteorological Department (IMD) is the nodal agency for early warning of cyclones and floods.
Natural Disaster Management Authority is mandated to deal with the disaster management in India. It has prepared National Guidelines on Management of Cyclone.
National Cyclone Risk Mitigation Project (NCRMP) was launched by Home ministry to upgrade the forecasting, tracking and warning about cyclones in states.
National Disaster Response Force (NDRF) has done a commendable performance in rescuing and managing relief work.
National Disaster Response Reserve (NDRR)– a fund of 250 crores operated by NDRF for maintaining inventory for an emergency situation.
In 2016, a blueprint of National Disaster Management Plan was unveiled to tackle disaster. It provides a framework to deal with prevention, mitigation, response and recovery during a disaster. According to the plan, Ministry of earth science will be responsible for disaster management of cyclone. By this plan, India joined the list of countries which follow the Sendai Framework for Disaster Risk Reduction 2015-2030.
Due to increased awareness and tracking of Cyclone, the death toll has been reduced substantially. For example, Very severe cyclone Hudhud and Phailin claimed lives of around 138 and 45 people respectively, which might have been more. It was reduced due to the early warning and relocation of the population from the cyclone-hit areas. Very severe cyclone Ockhi claimed many lives of people in Tamil Nadu and Kerala. This was due to the unprecedented change in the direction of the cyclone.
But the destruction of infrastructure due to cyclonic hit is not been reduced which leads to increase in poverty due to the economic weakening of the affected population.
