According to Council on Energy, Environment and Water (CEEW) India, in the last 50 years, has recorded a 12-fold surge in the number of associated cyclonic events such as extreme rainfall, floods, sea-level rise, and thunderstorms.
- Increased sea surface temperature: Over the past 50 years, the global ocean has absorbed 90% of the excess heat generated due to man-made climate change leading to higher convection and rapid intensification of cyclones.
- Rising sea level: on account of Antarctic melting has increased the moisture availability for cyclones.
- Micro-climatic changes on land: Local heating of coastal land is pulled by adjacent ocean further heating it up.
- Changing weather events: El-Nino and rising marine heat waves lead to prolonged warm periods over oceans by reducing the ocean upwelling.
- Higher Atmospheric moisture: due to anthropogenic global warming increase cyclonic precipitation rates thereby increasing the frequency.
- Changes in wind systems: Occasionally intense winds drive the low-pressure regions to other areas rising the frequency in those areas. Ex. Gulab cyclone shifted to Arabian sea from B.O.B.
According to NOAA, when the speed of a storm increases by 55km/hr within the span of 24 hours.
RECENT UNIQUE CYCLONIC PHENOMENON IN INDIA OCEAN
- Twin cyclones – Asani and Karim developing simultaneously in North and South of the Equator (May 2022). Madden-Julian Oscillation helped fuel the twin storms by promoting convection and strong westerly winds.
- Shifting of Gulab from B.O.B to Arabian sea under the influence of trade winds (Sept 2021).
- ‘Gaja,’ crossed Tamil Nadu and Puducherry coast in November 2018 and re-emerged in Arabian sea.
- Amphan (Super cyclonic storm in B.O.B)
- Ockhi (Nov 2017) intensified from a deep depression to a cyclonic storm in less than six hours and developed near the south-eastern coast of Sri Lanka’s teardrop. (There are only three instances of such a path being taken by any cyclone on record. The last time a track like this was witnessed was in 1925.)
- Fani had a longer span (more than 10 days) and it developed very close to equator.