IIT Kharagpur, Taiwan institute undertake study of cyclones

KOLKATA: Scientists from Indian Institute of Technology (IIT) Kharagpur and Institute of Earth Sciences, Academia Sinica, Taiwan have arrived at a mechanism to trace the source that supplies moisture to severe cyclonic storms.

The study indicates that the cyclone movement through the atmosphere continuously scavenges the existing vapour over the vortex cross-section much like a moving suction pump and provides the first experimental evidence of a theoretical model, an IIT Kharagpur statement said on Wednesday quoting Anindya Sarkar, Professor, Department of Geology. "Climate change due to global warming projects that the frequency of category 4 and 5 storms (60 to >70 m/s sustained wind speed) will be doubled by the end of the 21st century. We studied four such recent severe storms, named Nepartak, Meranti, Malakas and Megi - of category 4/5 - which had devastated Taiwan in a single year of 2016," he was quoted as saying.

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The statement quoted a former visiting Professor at IIT Kharagpur and the lead author of the paper Sourendra Bhattacharya as having said - "the cyclone during its journey keeps shedding enormous amount of rain which causes a progressive reduction in the ratio of the isotopes of Oxygen and Hydrogen in the leftover vapour mass. We tracked this magnitude of reduction, calculated and modelled to see how much rains were scavenged by these moving cyclones." The statement quoting Prof Mao-Chang Liang of Academia Sinica said, "We placed a mass spectrometer on top of a tall building to continuously measure the isotopes of Oxygen and Hydrogen in the vapour as these typhoons approached Taiwan. This technique provided us real-time variation inside typhoons every ten minute as it was raining and vapour compositions changed."

"Since both cyclone frequency and intensities are rising due to on-going climate change, this observation will be very important while studying the tropical cyclones that recurrently hit both India and Taiwan/Japan region, It also opened up avenues for future collaboration between the two countries," Liang said. Many houses were damaged and several casualties were reported in Bangladesh as Cycle Sitrang battered coastal districts of the country on October 25 night as the most recent instance of cyclone damage. An IIT Kharagpur spokesperson said with the help of the model the cyclones which lash the coastal belts of the region every year can be analysed including the factors behind the intensity of cyclonic winds and rains.