Indian scientists have come up with a promising technique for early detection of development or strengthening of tropical cyclones in the atmosphere for the Bay of Bengal basin, at least four days before satellite detects them over ocean surface in North Indian Ocean region.

So far, the remote sensing technique has detected the cyclones at the earliest, reports our New Delhi correspondent.

However, detection by remote sensing is possible only after the cyclone system is developed as a well-marked low-pressure system over the warm ocean surface.

A team of scientists including Jiya Albert, Bishnupriya Sahoo, and Prasad K Bhaskaran from Indian Institute of Technology in Kharagpur, West Bengal, with support from the Indian government's Department of Science and Technology, has devised a "novel" method using "Eddy" detection technique to investigate the formative stages and advance detection time of tropical cyclogenesis in the North Indian Ocean where cyclones in the Bay of Bengal are born, says a research study published in the journal 'Atmospheric Research' recently.

"The technique was found to have potential for early detection of tropical cyclogenesis in the atmospheric column prior to satellite detection over ocean surface," the study said, adding that it would allow a bigger time gap between the detection and the impact of the cyclone that could help preparation for facing it.

Prior to the formation of cyclonic system over the warm oceanic environment, the initial atmospheric instability mechanism, as well as the vortex development, is triggered at higher atmospheric levels, says the study.

The method developed by the scientists' aims to identify initial traces of pre-cyclonic eddy vortices in the atmospheric column and track its "Spatio-temporal evolution". They used coarser grid resolution of 27 km for identification and finer resolution of 9 km to evaluate the characteristics of eddy vortices, it said.

The study was conducted with cases of four post-monsoon severe cyclones -- Phailin (2013), Vardah (2013), Gaja (2018), Madi (2013) -- and two pre-monsoon cyclones -- Mora (2017) and Aila (2009) -- that had developed over North Indian Ocean.

The team observed that the method could bring about genesis of prediction with a minimum of four days' lead time for cyclones developed during the pre-and post-monsoon seasons.

Initiation mechanisms of genesis of tropical cyclones occurs at upper atmospheric levels and are also detected at higher lead time for pre-monsoon cases, unlike the post-monsoon cases, said the study.