Cyclones are intense weather systems with low atmospheric pressure and rotating winds, forming over warm tropical waters. These storms cause severe weather, including heavy rainfall, strong winds, and storm surges. Cyclones are categorized based on wind speeds, from tropical depressions to severe cyclonic storms. Warm ocean surfaces and high humidity fuel these storms, with atmospheric conditions like wind shear and moisture influencing their strength and formation.

The North Indian Ocean plays a key role in global weather systems, particularly the summer monsoon. Warm waters from the Arabian Sea and Bay of Bengal are crucial for moisture generation during monsoon seasons. However, despite the warm ocean surfaces that typically promote cyclones, this region has fewer cyclones compared to other tropical oceans. A mix of factors—both promoting and suppressing cyclone formation—makes the North Indian Ocean a unique and less cyclone-prone area.

The Indian Ocean stands out due to its monsoonal circulation, marked by seasonal wind reversals north of the equator. It also has "oceanic tunnels" connecting it to the Pacific and Southern Oceans, which influence its weather. The Pacific tunnel introduces warm water into the upper layers, while the Southern Ocean brings cooler waters into deeper levels. These oceanographic features contribute to distinct weather patterns, including influencing the formation and behavior of cyclones.

As the pre-monsoon season begins and the Sun moves into the northern hemisphere, the Arabian Sea rapidly warms. The Bay of Bengal, typically warmer, heats further, driving atmospheric convection and rainfall. These warming patterns make the Bay of Bengal more prone to cyclones, while the Arabian Sea, with its cooler waters and stronger wind shear, experiences less cyclone activity. These conditions contribute to significant differences in cyclone formation between the two seas.

Impact of Climate Change on Cyclones in the Indian Ocean

Climate change is amplifying the Indian Ocean’s warming, bringing in more heat from the Pacific Ocean while the Southern Ocean pushes warmer waters into deeper layers. These changes, combined with shifts in winds and atmospheric humidity, are causing the Indian Ocean to warm at a rapid pace. This warming is affecting cyclone formation, increasing the frequency and intensity of storms. The Indian Ocean acts as a "clearinghouse" for ocean warming, impacting global weather patterns and intensifying cyclone activity.

Monsoon and Cyclone Seasons in the North Indian Ocean

• The monsoon heavily influences cyclone activity in the region. During the monsoon, strong winds cool the Arabian Sea, reducing the likelihood of cyclone formation. In contrast, the Bay of Bengal sees more low-pressure systems, although many do not become cyclones due to wind shear that weakens their energy.
• The North Indian Ocean experiences two distinct cyclone seasons—pre-monsoon and post-monsoon—unlike other regions that typically have just one. Cooler temperatures and stronger wind shear keep cyclone numbers low in the Arabian Sea, compared to the Bay of Bengal.
• Cyclone Asna, formed in August 2023, was a rare cyclone for this time of year. It developed from a land-based depression that moved over the Arabian Sea, marking the first August cyclone in the region since 1981. This rare occurrence highlights how rapidly warming oceans, influenced by climate change and El Niño, can drive unexpected cyclone formations.