Tags:
- GS Paper – 1
- Physical Geography
- Cyclone
- Important Geophysical Phenomena
- GS Paper – 3
- Disaster Management
For Prelims: Cyclone Dana, Bhitarkanika National Park, Storm Surges, North Indian Ocean Region, Monsoon, Atmosphere, Cumulonimbus Clouds, Madden Julian Oscillation (MJO), World Meteorological Organization (WMO), Building Code, Cyclone Warning System, Mangroves.
For Mains: Formation of Cyclones, Cyclone Disaster Preparedness and Mitigation
Source: DTE
Why is Cyclone Dana in the News?
The India Meteorological Department (IMD) has reported that Cyclone Dana is projected to make landfall as a severe cyclone, with wind speeds ranging from 89 to 117 km/h, along the coast of Odisha, specifically near Bhitarkanika National Park and Dhamra Port.
Key Facts About Cyclone Dana
- Emergence: Cyclone Dana is notable as the third cyclone to develop in the North Indian Ocean region and the second to hit the Indian coast in 2024, following Cyclone Remal. It is also the first cyclone of the post-monsoon season.
- Naming: The World Meteorological Organization (WMO) indicates that the cyclone has been named “Dana” by Qatar.
- In Arabic, “Dana” means ‘generosity’ and is associated with ‘the most perfectly sized, valuable, and beautiful pearl.’
Causes of Intense Rainfall:
- Intense Convection: Cyclone Dana exhibits significant convection in its western sector, extending to the upper atmosphere. This intense convection arises when warm, moist air ascends, cools, and expands, leading to condensation of moisture into water droplets, forming clouds. The ongoing cooling and condensation produce cumulonimbus clouds typical of thunderstorms, resulting in conditions favorable for heavy rainfall.
- Warm Moist Air Influx: The cyclone experiences an influx of warm, moist air into its core, which enhances convection and increases the intensity of rainfall. This process is crucial for maintaining and intensifying the cyclone’s strength, leading to significant rainfall over a localized area.
- Madden Julian Oscillation (MJO) Influence: The current phase of the MJO favors convection and consequently heavy rainfall. The MJO comprises two phases: an enhanced rainfall phase and a suppressed rainfall phase. During the enhanced phase, surface winds converge, facilitating air ascent and increased rainfall. Conversely, in the suppressed phase, winds at the upper atmosphere cause air to sink, resulting in decreased rainfall. This oscillation moves west to east in the tropics, leading to variations in cloudiness and rainfall patterns.
Key Points About Cyclone Naming
Historical Context:
The practice of naming storms originated in the late 1800s in the Caribbean, where storms were named after saints from the Roman Catholic calendar. Following World War II, female names became common to streamline storm tracking. However, this approach faced criticism for gender bias, leading to an update in 1979 that alternated between male and female names.
Establishment of Naming Systems:
The naming of cyclones in the North Indian Ocean region began in 2000 under the auspices of the WMO. A collaborative naming list was created by the Tropical Cyclone Regional Body (TCRB), which comprises 13 member countries: Bangladesh, India, Maldives, Myanmar, Pakistan, Sri Lanka, Oman, Thailand, Iran, Qatar, Saudi Arabia, United Arab Emirates, and Yemen.
Name Submission Process:
Each member country submits 13 name suggestions to a WMO panel, which reviews and finalizes the names.
Global Standardization:
Naming cyclones aids in their identification by the media and the public, facilitating awareness of their progression and potential threats.
Rotation and Retirement of Names:
The names on the cyclone list are periodically rotated to introduce new selections. Retired names, particularly those associated with devastating storms, are replaced to avoid negative connotations.
Factors Contributing to the Formation of Tropical Cyclones
- Warm Ocean Waters: A sea surface temperature of at least 27°C is vital for tropical cyclone development, as warm water supplies the heat and moisture necessary for rising air and the convection process.
- Coriolis Force: The Coriolis effect, resulting from Earth’s rotation, is essential for imparting spin to the cyclone. This force is minimal near the equator, hence tropical cyclones typically form at least 5° north or south of it.
- Low Wind Shear: Low vertical wind shear, which refers to the variation in wind speed and direction at different altitudes, is crucial. High wind shear can disrupt the storm’s vertical structure, hindering its strengthening.
- Pre-existing Disturbance: A tropical disturbance, such as a low-pressure system, provides the initial air circulation organization necessary for cyclone formation.
- Convergence of Air: The convergence of warm, moist air at the surface is fundamental for developing the cyclone’s core, as it leads to the creation of clouds and thunderstorms.
Impacts of Cyclones
- Human Impact: Cyclones can lead to significant casualties due to their strong winds, storm surges, and flooding, displacing thousands and resulting in temporary or permanent loss of homes.
- Infrastructure Damage: Powerful winds can cause power outages and structural damage, while flooding can disrupt transportation and communication systems.
- Environmental Consequences: Cyclones erode coastlines with high winds and storm surges, damaging natural habitats and human structures along the shore. They can inflict long-term damage on forests, wetlands, and marine ecosystems, adversely affecting biodiversity.
- Agricultural Damage: Low-lying agricultural areas are particularly susceptible to seawater intrusion and waterlogging from heavy rainfall, potentially destroying crops and reducing agricultural productivity. Prolonged rainfall can lead to water accumulation in fields, negatively impacting soil health and crop yields.
Four-Stage Cyclone Warning System
- Pre-Cyclone Watch (Green): Issued 72 hours before adverse weather, this alerts communities about potential cyclonic disturbances.
- Cyclone Alert (Yellow): Issued at least 48 hours in advance, providing information on the storm’s location and advising on safety measures.
- Cyclone Warning (Orange): Issued 24 hours before adverse weather onset, this includes detailed updates on cyclone position and expected impacts.
- Post Landfall Outlook (Red): Issued 12 hours before landfall, this offers insights into adverse weather conditions likely to affect inland areas post-landfall.
Measures for Effective Cyclone Disaster Preparedness and Mitigation
Before a Cyclone:
- Land Use Planning: Implement regulations to limit habitation in vulnerable zones, repurposing them for parks or flood diversions.
- Cyclone Early Warning System: Utilize an Impact-Based Cyclone Warning System to effectively communicate risks and preparedness actions, focusing on local populations.
- Engineered Structures: Construct buildings capable of withstanding cyclone winds, particularly essential public infrastructure like hospitals and communication towers.
- Mangrove Plantations: Encourage community participation in mangrove planting initiatives to protect coastal areas from storm surges and erosion.
During a Cyclone:
- Cyclone Shelters: Establish shelters in high-risk areas, ensuring they are accessible via major roads for quick evacuation.
- Flood Management: Develop sea walls, embankments, and drainage systems to control water flow and mitigate flooding from storm surges and heavy rain.
After a Cyclone:
- Hazard Mapping: Create maps indicating the historical frequency and intensity of cyclones, incorporating storm surge and flooding risks.
- Retrofitting Non-Engineered Structures: Educate communities on techniques to enhance the resilience of homes, such as constructing steep-slope roofs and securing poles.
Conclusion
Cyclone Dana highlights the critical need for proactive disaster management measures, including effective early warning systems, comprehensive land use planning, and community engagement. By bolstering infrastructure resilience, implementing hazard mapping, and promoting mangrove conservation, we can enhance our preparedness for and mitigation of cyclone impacts on vulnerable coastal areas.
UPSC Civil Services Examination Previous Year Question (PYQ)
Prelims Q: Consider the following statements: (2020)
- Jet streams occur in the Northern Hemisphere only.
- Only some cyclones develop an eye.
- The temperature inside the eye of a cyclone is nearly 10ºC less than that of the surroundings.
Which of the statements given above is/are correct?
(a) 1 only
(b) 2 and 3 only
(c) 2 only
(d) 1 and 3 only
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