Complex and Unique Characteristics of the North Indian Ocean
Geographical Features: Includes the Arabian Sea, Bay of Bengal, and the Andaman Sea, each with distinct characteristics.
Experiences significant seasonal temperature changes, with
Arabian Sea warming rapidly in pre-monsoon
Bay of Bengal staying warmer overall.
Oceanic Tunnels: Connected to the Pacific Ocean by warm upper waters and to the Southern Ocean by cooler deep waters, affecting its thermal properties.
Role in Influencing the Summer Monsoon and Cyclogenesis
Summer Monsoon
The North Indian Ocean supplies moisture essential for the summer monsoon, with warm seas facilitating high evaporation rates.
The Bay of Bengal's warming drives convection and rainfall, affecting the onset of the monsoon season over India.
Cyclogenesis
Warm sea surface temperatures and significant evaporation contribute to cyclone development.
Cyclones typically form during pre-monsoon and post-monsoon seasons, with less activity during the monsoon due to strong wind shear.
Unusual Cyclone Events
Cyclone Asna (August 2023)
First North Indian Ocean cyclone in August since 1981, forming from a strong land-born depression transitioning to the warm Arabian Sea.
The cyclone's development was atypical, originating over land and intensifying over the ocean, reflecting the impact of rapid warming and climatic changes.
Despite some increase in cyclone numbers since 2010, the Arabian Sea has seen a notable decrease in cyclone activity in recent years.
Cyclone Asna
This is the first cyclonic storm in the Arabian Sea in August since 1976
Since 1891, only three cyclonic storms have occurred in the Arabian Sea in August, with the most recent one before 2023 being in 1976.
Cyclone Asna, named by Pakistan, means “the one to be acknowledged or praised.”
Cyclone Asna has formed over the Kutch coast in Gujarat and adjoining areas of Pakistan.
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