Relevance: mains: G.S paper I: Geography
RIMES
The RIMES is an intergovernmental body registered under United Nations.
It is owned and managed by 45 collaborating countries in Asia Pacific and Africa Region.
It seeks to establish regional early warning system within multi-hazard framework for generation and communication of early warning information and capacity building for preparedness and response to trans-boundary hazards.
It provides information related to Tsunami and extreme weather conditions. It also acts as a test bed for emerging technologies and help to enhance performance
What is a cyclone?
A “Cyclone” is an intense vortex or a whirl in the atmosphere with very strong winds circulating around it in anti-clockwise direction in the Northern Hemisphere and in clockwise direction in the Southern Hemisphere. Characteristics:
Cyclones are intense low pressure areas – from the centre of which pressure increases outwards
The amount of the pressure drop in the centre and the rate at which it increases outwards gives the intensity of the cyclones and the strength of winds.
Cyclones are of two types: Temperate cyclone and Tropical cyclone. Tropical Cyclones are among the most destructive phenomena.
Tropical Cyclones:
It is a system of low pressure occurring in tropical latitudes
The differential heating over land and sea probably causes a small area of low atmospheric pressure to develop.
Tropical cyclone activity is at its maximum in late summer and early autumn
Tropical cyclones follow a parabolic path; their axis being parallel to the isobars.
Necessary Conditions for development of a tropical cyclone and Formation:
- Continuous supply of abundant warm and moist air
- Sea temperature in lower latitudes should be around 27°C
- A distance from the Equator is necessary, so that it allows the Coriolis effect to deflect winds blowing toward the low pressure centre. They develop in inter-tropical convergence zone
- Pre-existence of weak tropical disturbances
- Presence of anticyclonic circulation at the height of 9 to 15km above the surface
- Low vertical wind shear between the surface and the upper troposphere. Vertical wind shear is the magnitude of wind change with height. Anatomy of a Tropical Cyclone:
Eye: The central calm region of the storm is called the “Eye”.
Eye wall: It is the region with heaviest precipitation and strongest winds.
Formation of a Tropical Cyclone:
To form a cyclone, warm, moist air over the ocean rises upward from near the surface. As this air moves up and away from the ocean surface, it leaves is less air near the surface. So basically as the warm air rises, it causes an area of lower air pressure below.
Air from surrounding areas with higher air pressure pushes in to the low pressure area. Then this new “cool” air becomes warm and moist and rises, too. And the cycle continues
As the warmed, moist air rises and cools the water in the air forms clouds. The whole system of clouds and wind spins and grows, fed by the ocean’s heat and water evaporating from the ocean surface.
As the storm system rotates faster and faster, an eye forms in the centre. It is very calm and clear in the eye, with very low air pressure. Higher pressure air from above flows down into the eye
Tropical cyclones usually weaken when after they hit land (landfall), because they are no longer being fed by the energy from the warm ocean waters.
Cyclones in India: Cyclones mainly occur during post monsoon and less in pre-monsoon and monsoon season. Cyclones affect both the Bay of Bengal and the Arabian Sea; however, the Bay of Bengal witness more cyclones than the Arabian Sea. This is because:
Bay of Bengal has higher ocean surface temperature than the Arabian Sea. This helps in formation and intensification of cyclonic storms
High rainfall and inflow of fresh water:
The Bay receives higher rainfall and constant inflow of fresh water. Therefore, the its surface water keeps getting refreshed, making it impossible for the warm water to mix with the cooler water below, making it ideal for a depression.
On the other hand, enhanced vertical mixing in the Arabian Sea, limits cyclone intensification
Role of remnants:
Cyclones that form over the Bay of Bengal are either those develop insitu over southeast Bay of Bengal and adjoining Andaman Sea or remnants of typhoons over Northwest Pacific and move across south China sea to Indian Seas. As the frequency of typhoons over Northwest Pacific is quite high, the Bay of Bengal also gets higher number of cyclones.
On the other hand, the cyclones over the Arabian Sea either originate insitu over southeast Arabian Sea or remnants of cyclones from the Bay of Bengal that move across south peninsula. As the majority of Cyclones over the Bay of Bengal weaken over land after landfall, the frequency of migration into Arabian Sea is low.
How are Cyclones named?
In the beginning, storms were named arbitrarily.
The tradition of naming cyclones started with hurricanes in the Atlantic Ocean, where tropical storms that reach sustained wind speeds of 39 miles per hour were given names
In 1953, the US weather service officially adopted the idea and created a new phonetic alphabet (international) of women’s names from A to W, leaving out Q, U, X, Y and Z.
Male names were included in 1978.
The process of naming cyclones involves several countries in the region and is done under the aegis of the World Meteorological Organization.
For the Indian Ocean region, deliberations for naming cyclones began in 2000. A formula was adopted in 2004.
How has naming a cyclone helped?
It helps in the quick identification of storms in warning messages
Names are presumed to be far easier to remember than numbers and technical terms.
Giving names to storms makes it easier for the media to report on tropical cyclones, heightens interest in warnings and increases community preparedness
Pre-Disaster
Structural Measures: Structural measures include construction of cyclone shelters, construction of cyclone resistant buildings, road links, culverts, bridges, canals, drains, saline embankments, surface water tanks, communication and power transmission networks etc.
Non-Structural Measures: Non-structural measures include early warning dissemination systems, management of coastal zones, awareness generation and disaster risk management and capacity building of all the stakeholders involved.
During Disaster: Immediate rescue operations, supply of water, medicines, food and other necessary items, Damage assessments
Post Disaster: Rehabilitation, Providing financial assistances, arrangements of relief measures.
Government Initiatives National Cyclone Risk Mitigation Project (NCRMP) Aim: The scheme aims to:
Upgrade cyclone forecasting, tracking and warning systems, build capacity in multi-hazard risk management
Construct major infrastructures including multi-purpose cyclone shelters and embankments.
Principal Components:
The major components under the scheme are:
- Community mobilisation and training
- Cyclone Risk Mitigation Infrastructure (construction of cyclone shelters, roads/missing links and construction/repair of Saline Embankments etc.)
- Technical assistance for capacity building on Disaster Risk Management (risk assessment, damage and need assessment)
- Capacity Building and knowledge creation along with project management and implementation support
- Integrated Coastal Zone Management Project (ICZMP)
It is a World Bank assisted project which aims at national capacity development for implementation of comprehensive coastal management in India.
Broad objectives of the project include:
Cyclone forecasting
Tracking and warning systems
Cyclone Risk Mitigation and Capacity Building
Major infrastructure to be constructed under multipurpose cyclone shelters, access roads, underground cabling and saline embankments
Disaster Mitigation
Lowering loss of lives, property in vulnerable states
NDMA Guidelines:
Establishment of exclusive eco-system monitoring network to study the impact of climate change
Adoption of Aircraft Probing of Cyclone (APC) facility to fill the critical observational data gaps and significantly reduce the margin of error in predicting cyclone track, intensity and landfall
Establishment of a comprehensive Cyclone Disaster Management Information System (CDMIS)
Establishment of a state-of-the-art cyclone early warning system (EWS) involving observations, predictions, warnings and user friendly advisories
Structural mitigation should be taken up which include- improvement in structural lifeline infrastructure, construction of multi-purpose cyclone shelters and cattle mounds, ensuring cyclone resistant design standards in rural and urban housing schemes, building all-weather road links, bridges, culverts and saline embankment
Management of coastal zones should include mapping and delineation of coastal wetlands, patches of mangroves and shelterbelts and identification of potential zones for expanding bio-shield spread based on remote sensing tools.
Way Forward:
The Early Warning System for cyclones should be strengthened to ensure timely and accurate information about cyclone- its track, intensity, time of landfall and likely impacts.
It is important to ensure timely dissemination of warning. IMD’s cyclone alerts should be disseminated by broadcasters to all levels of governance and public
The disaster management authorities should be more proactive in search and rescue operation after a cyclone disaster so that the loss of life can be negated.
There should be proper coordination between the Centre, State and several Government agencies, and trained personnel for prompt and organised response after a cyclone.
Structural measures such as designing and building of robust cyclone proof shelters, ensuring availability of essential infrastructure is important.
Rapid urbanization and increasing encroachment in coastal areas is a major problem. Coastal Regulation zone norms should be strictly enforced.
Awareness generation among all stakeholders is important for cyclone risk mitigation.