Hyderabad: The Indian Ocean saw eight cyclones in 2019, 400 per cent higher than the historical normal dating from 1902. The Arabian Sea saw five major intense high-frequency cyclones, over the normal one per year. The warm seas caused the abnormally high Indian Ocean Dipole (IOD) which in 2019 was two degrees above normal, leading to the unusually dry weather in Australia that triggered the recent devastating forest fires, say experts.
“The 2019 IOD is the highest on record,” said a senior weather department official in Hyderabad. “West Indian Ocean surface temperatures led to intense cyclones and continued to be abnormally active. Interestingly, the Bay of Bengal which is otherwise active was calm and cool.”
The Arabian Sea saw two simultaneous cyclones in August 2019, also a first in recorded history. This caused the revival of the south west monsoon and also the month-late withdrawal of monsoon from the country.
These conditions in the west Indian Ocean produced clouds and rain in the western region of India but led to severe dry weather conditions over Australia.
"The IOD influences Australian weather," said Rajanikanth Poolla, weather expert. "Low IOD will bring rains and floods while high IOD will lead to dry and drought conditions in Australia. This is because the Australian west coast warms up along with the surface air over the sea. With high IOD there is no cloud formation and that leads to extensively dry conditions associated with bush fires. As in 1982 there were forest fires in Australia due to a combination of the high IOD levels and the El-Nino in the Pacific Ocean. In 2019-20, the unusually high IOD is influencing the outbreak of forest fires."
The intensely warm Arabian Sea has led to many first experiences for India in 2019 and is spilling over to Australia in 2020.
Warm sea is being attributed to changing climate conditions and weather experts believe that erratic and sudden changes in weather will be the new norm.
