IIT Kharagpur researchers say their technique can detect cyclones much in advance
Researchers at the Indian Institute of Technology, Kharagpur and Yantai Institute of Coastal Zone Research in China have developed a technique that can detect the forming of cyclone in the North Indian Ocean region much in advance. “Before they are picked up by the weather satellites orbiting the Earth,” the researchers claimed.
“Basically eddies are disturbances that we find in the atmospheric column where the cyclone initiates. A cyclone is first formed 7-8 kilometres in the upper atmosphere. The instability in the higher atmosphere leads to eddies that are weather instabilities. So, we found that pre-cyclonic eddies form in the atmosphere and after they grow they start migrating up and down. However, this detection was possible only after the system developed as a well-marked low-pressure system over the warm ocean surface. Our study can detect a possible cyclone from the time the eddy is formed,” said Prasad K Bhaskaran, IIT Kharagpur.
The study conducted under the Climate Change Program with support from the Centre’s Department of Science and Technology, and published in the journal Atmospheric Research, identified pre-cyclonic eddy in the upper atmosphere before they turned into depression and subsequently into cyclonic storms.
The research team, comprising Prasad K Bhaskaran and Jia Albert of IIT Kharagpur and Bishnupriya Sahu of Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China, claimed that it can detect at least 90 hours before the weather satellites pick up the data from the ocean surface.
The research team which analysed four post-monsoon severe cyclones — Phailin (2013), Vardah (2013), Gaja (2018), Madi (2013) - and two pre-monsoon cyclones Mora (2017) and Aila (2009) that developed over the North Indian Ocean, came out with a threshold value of a parameter called Okubo-Weiss Zeta Parameter. “When the parameter crossed the threshold value, it resulted in the formation of a cyclone,” he said.
Bhaskaran said once the satellites detect the depression, then weather agencies like the India Meteorological Department (IMD) run the weather models predicting the cyclone’s landfall. “The model that we have developed gives a larger time gap between the detection and the cyclone’s landfall that would help in evacuation activities. Currently, cyclones take anything between 5 and 7 days between their formation and landfall. Our model would give 4 days of additional lead time to governments in preparing for the cyclones and save lives,” he said.
The research team found that the bottom of the oceans are getting much warmers and this could lead to stronger cyclones in the future. “Warm ocean temperatures are what fuel cyclones. With ocean temperature, 500 metres below the surface, warmer than what it is on top, we expect the cyclones to be much more intense. Earlier, most cyclones were formed in the Bay of Bengal. Now the Arabian Sea is going to be the breeding place of stronger cyclones,” the team found out.