Context: The India Meteorological Department (IMD) has issued a warning about weather changes in Maharashtra due to a possible Cyclone Tej that is expected to develop in the Arabian Sea.

Current Status of Cyclone Tej

• According to India Meteorological Department (IMD), cyclonic storm is predicted to cross the Yemen-Oman coasts on October 24 as a very severe cyclonic storm with wind speeds of 115-125 kmph, gusting to 140 kmph, the IMD said.
• According to IMD, in next six hours, the cyclone will move North wards and weaken into ‘very severe cyclonic storm’.
  • Cyclone is very likely to cross the Yemen-Oman coast between Al Ghaidah in Yemen and Salalah in Oman in the early hours of October 25
• In the western Arabian Sea, very rough sea conditions are likely to prevail from October 22 to 25.
• The cyclonic storm will not have any impact on Gujarat.

Arabian Sea Alert: Cyclone Tej Approaches

• About: Cyclone Tej is the first post-monsoon cyclone of the 2023 season in the Arabian Sea. 
  • It has been named by India. 
• Origin: Cyclone Tej originated as a low-pressure area over the southeast Arabian Sea that eventually intensified into a depression recently. 
• Trajectory: Cyclone Tej is currently moving west-north westwards towards the coast of Maharashtra and is expected to make landfall near Mumbai in the next few days.
  • Cyclone Tej  might result in heavy rains and strong winds causing storm surges and coastal flooding.

What are Cyclones?

• A Cyclone is a rapid inward air circulation around a low-pressure area. In other words, it is a low-pressure system that forms over warm waters.
• Cyclones in India: 
  • Tropical cyclones in the North Indian Ocean region (Bay of Bengal and  Arabian Sea) develop during the pre-monsoon (April to June) and post monsoon (October to December) periods.
  • Cyclone Tej is developing in the Arabian Sea. 

Understanding Cyclone Formation and Coriolis Effect

• Formation of Low Pressure: As air gets warm over hotter regions it ascends, leading to low pressure at the surface it is covering. In a depression or low-pressure situation, the air is rising and blowing in a specific direction around the low-pressure center. 
• Coriolis Effect: This direction is due to the Coriolis effect, which is the result of the Earth’s rotation on its axis. 
  • The Coriolis effect causes the air to deflect to the right in the Northern Hemisphere and to the left in the Southern Hemisphere, leading to the anticlockwise and clockwise circulation around the low-pressure center, respectively. 
  • This process is crucial in the formation and intensification of a cyclone, and it can lead to severe weather events such as heavy rainfall, strong winds, and storm surges.
• High Pressure: When air cools in colder areas it descends, leading to high pressure at the surface. 

Tropical Cyclones: Characteristics and Formation Stages

• Tropical cyclones: 
  • These are intense circular storms that originate over warm tropical oceans in tropical areas and move over to the coastal areas bringing about large scale destruction caused by violent winds, very heavy rainfall and storm surges.
  • They are characterized by low atmospheric pressure.
  • The conditions favourable for the formation and intensification of tropical storms are:
    • Large sea surface with temperature higher than 27° C.
    • Presence of the Coriolis force.
    • Small variations in the vertical wind speed.
    • A pre-existing weak low- pressure area or low-level-cyclonic circulation.
    • Upper divergence above the sea level system.
    • Cyclone Tej meets all the criteria to be classified as a tropical cyclone
• Stages of Formation: Tropical Cyclones
  • Formation Stage: It depends upon the transfer of water vapour and heat from the warm ocean to the overlying air, primarily by evaporation from the sea surface.
    • It encourages formation of massive vertical cumulus clouds due to convection with condensation of rising air above the ocean surface.
  • Mature Stage: When a tropical storm intensifies, the air rises in vigorous thunderstorms and tends to spread out horizontally at the tropopause level. 
  • Once air spreads out, a high pressure at high levels is produced, which accelerates the downward motion of air due to convection.
  • With the inducement of subsidence, air warms up by compression and a warm ‘Eye’ (Low pressure centre) is generated. 
  • The main physical feature of a mature tropical cyclone in the Indian Ocean is a concentric pattern of highly turbulent giant cumulus thundercloud bands.
• Modification and Decay
  • A tropical cyclone begins to weaken in terms of its central low pressure, internal warmth and extremely high speeds, as soon as its source of warm moist air begins to ebb or is abruptly cut off.
  • This happens after its landfall or when it passes over cold waters.
  • Cyclone Tej is expected to weaken upon reaching the land near Mumbai, which has prompted an alert for the city

Tropical Cyclones: Global Naming Conventions

• Typhoons: China Sea and Pacific Ocean; 
• Hurricanes: West Indian islands in the Caribbean Sea and Atlantic Ocean; 
• Tornados:Guinea lands of West Africa and southern USA.; 
• Willy-willies: North-western Australia.
• Tropical Cyclones: Indian Ocean.

Why generally cyclones do not form during the active monsoon season?  

• Vertical Wind Shear: During the monsoon season, there exists very high vertical wind shear due to strong monsoon currents. 
  • Vertical Wind shear is a change in wind speed or direction with a change in altitude.
• This dampens the intensification in strength and wind speeds of cyclones. As a result, clouds do not grow vertically and monsoon depressions often fail to intensify into cyclones.
• Strong opposing winds: Generally, the monsoon conditions are not favourable for cyclones to develop in the North Indian Ocean due to the presence of strong opposing winds i.e. “the lower atmospheric winds are in one direction (southwesterly) and the upper atmospheric winds are in the other direction (northeasterly). This prevents a cyclone from developing vertically.”

Cyclone Naming Protocol: Insights and Regulations by IMD

• Authorising Body: Cyclones are named by the regional specialized meteorological centers (RSMCs) and Tropical Cyclone Warning Centers (TCWCs) across the world. 
  • The India Meteorological Department (IMD) is one of the RSMCs and is responsible for naming cyclones that develop over the north Indian Ocean, including the Bay of Bengal and the Arabian Sea, by following a standard procedure. 
• In 2000, a group of nations comprising Bangladesh, India, the Maldives, Myanmar, Oman, Pakistan, Sri Lanka, and Thailand decided to start naming cyclones in the region. 
  • The cyclone names are assigned in a sequential manner, with names starting from A to Z, excluding Q, U, X, Y, and Z.

Impact of Climate Change on Cyclones: Trends and Foreseen Consequences”

• Impacting Cyclone Cycle: Climate change is expected to affect the frequency, intensity, and patterns of tropical cyclones. 
  • Warmer ocean temperatures, rising sea levels, and changes in atmospheric circulation patterns are all factors that contribute to the changing nature of tropical cyclones.
• Increase in Intensity: 
  • Warmer ocean temperatures provide more energy for tropical cyclones to form and strengthen, leading to more frequent and more severe storms. 
  • It has been observed that tropical cyclones that reach category 4 or 5 intensity have increased in recent decades.
• Changing Pattern: In some regions,frequency of tropical cyclones may decrease, while in others, it may increase.
  • For example, the number of Atlantic hurricanes may decrease in the future, while the number of storms in the Pacific may increase. 
• Rising sea levels: Higher sea levels mean that storm surges caused by tropical cyclones can penetrate further inland, causing more extensive damage and posing a greater risk to coastal communities.
• Increased Cyclonic Activity in the Arabian Sea: 
  • The Arabian Sea is a region of the northern Indian Ocean that is bounded by the Indian subcontinent to the east, the Arabian Peninsula to the west, and the Somali Peninsula to the south. 
  • This region has seen relatively few tropical cyclones compared to other parts of the world, such as the Western Pacific and the Atlantic. 
  • However, in recent years, the number of cyclones forming in the Arabian Sea has increased by about 50% over the past four decades, and the trend is expected to continue in the future due to rising sea surface temperatures.

Comprehensive Strategies for Effective Cyclone Management and Mitigation

• Implement Long-term Mitigation Measures: Focus on cost-effective, long-term solutions such as building cyclone-resistant infrastructure, enhancing river connectivity to prevent waterlogging, installing disaster-resilient power systems, and conducting awareness campaigns.
• Enhance Early Warning Systems: Improve and expand efficient early warning systems to provide timely information for preparation and evacuation, ensuring coverage of all affected areas.
• Construct Safe Evacuation Shelters: Build secure evacuation shelters in cyclone-prone districts to provide a safe refuge for people during cyclones.
• Strengthen Disaster Preparedness: Enhance disaster management activities to ensure prompt and efficient delivery of relief to those in need.
• Restore Mangrove Ecosystems: Emphasize the regeneration of mangroves in coastal regions, as they act as natural barriers against storm surges, minimizing cyclone impact.
• Facilitate Coordination Between Centre and States: Foster strong coordination between the central government and state authorities for effective design and implementation of disaster mitigation measures.
• Capacity Building for Stakeholders: Provide training and capacity building for all stakeholders involved in disaster management, including government officials, first responders, and the public, to enable coordinated and effective responses to cyclones.