Odisha scientist Bishnupriya Sahoo devises method for detection of cyclones over BoB earlier than satellites

Bhubaneswar: A team of scientists comprising Odisha-born Bishnupriya Sahoo, Jiya Albert and Prasad K. Bhaskaran from IIT Kharagpur, with support from the Department of Science & Technology, Government of India under the Climate Change Programme (CCP) has devised a promising technique for early detection of development or strengthening of tropical cyclones in the atmospheric column prior to satellite detection over Bay of Bengal (BoB) basin.

Speaking to Sambad English, Sahoo said, “The tropical cyclone intensity in the Bay of Bengal and frequency of pre-monsoon cyclones striking the Odisha coast are in the increasing trend. Interestingly, this recent research found that the initiation disturbances that occur at upper atmospheric levels can be detected at a higher lead time for pre-monsoon cases, unlike the post-monsoon cases. Early detection and preparedness mechanism much prior to the landfall of a tropical cyclone hold immense potential for Odisha, the most cyclone-affected state in India.”

A researcher in Physical Oceanography, Sahoo currently works as a Research Scientist at the Yantai Institute of Coastal Zone Research, China. She pursued her Ph.D at IIT Kharagpur in Physical Oceanography from 2014 to 2018.

Sahoo pursued her MSc in Mathematics at NIT, Rourkela (2010-2012), BSc at Rama Devi Women’s Autonomous College, Bhubaneswar (2007-2010) and +2 Science at the same college from 2005 to 2007. Her schooling took place at the Basipitha Government High School, Mayurbhanj.

Early detection of tropical cyclones has wide socio-economic implications. So far, remote sensing techniques have detected them the earliest. However, this detection was possible only after system developed as a well-marked low-pressure system over the warm ocean surface. A larger time gap between the detection and the impact of the cyclone could help preparation activities.

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. These cyclonic eddies are prominent features in the vertical atmospheric column encompassing the disturbance environment with a potential to induce and develop into a well-marked cyclonic depression over the warm ocean surface. They could be used for detection of prediction of cyclones.

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. 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 developed over North Indian Ocean.

The team observed that the method could bring about genesis of prediction with a minimum of four days (~ 90 h) 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. The study made a comprehensive investigation on the behavior of eddies in an atmospheric column for non-developing cases and compared these findings with developing cases.

The technique was found to have potential for early detection of tropical cyclogenesis in the atmospheric column prior to satellite detection over ocean surface.