Global warming triggering rapid intensification of tropical cyclones: INCOIS study

HYDERABAD: A growing number of cyclones are experiencing multiple rapid intensifications globally, posing substantial challenges to cyclone forecasting, according to a new study published recently in Scientific Reports.

Rapid intensification is a process where a tropical cyclone intensifies dramatically in a short period (an increase in the cyclone's intensity of 30 knots or more in 24 hours).

Cyclones' forecasting can become more challenging if they have experienced rapid intensification multiple times in their lifetime, highlighting the increased unpredictability of their behavior.

The study was conducted by researchers from the Indian National Centre for Ocean Information Services (INCOIS) in Hyderabad and the Department of Meteorology and Oceanography, College of Science and Technology, Andhra University in Visakhapatnam.

Effect of Global Warming

The study also noted that global warming has heightened cyclone intensity, increasing the likelihood of multiple rapid intensifications.

“We observed that tropical cyclones are intensifying more rapidly and more frequently. We also found changes in the life cycle of tropical cyclones. Previously, this rapid intensification used to occur during the initial stages of cyclones’ life, but now, with ocean warming, this rapid intensification continues to occur even in the mature stages of cyclones’ life,” explained N. D. Manikanta, Project Scientist at INCOIS and first author of the paper.

Warming of the surface ocean from anthropogenic climate change fuelled more powerful tropical cyclones. Rising coastal populations and increasing infrastructure value in coastal areas in developing countries necessitate accurate prediction of cyclone intensity and landfall.

The study underscored the crucial role of understanding the effects of human activities and global warming on the rapid intensification of cyclones.This study also highlighted the vital importance of better forecasting and preparedness to preserve coastal communities and infrastructure.

Cyclone Data

The team used publicly available tropical cyclone data from the International Best Track Archive for Climate Stewardship (IBTrACS) project, which was developed collaboratively with all the World Meteorological Organisation (WMO) Regional Specialised Meteorological Centres, as well as other organisations and individuals from around the world.

This project merged recent and historical tropical cyclone data from multiple agencies to create a unified, publicly available dataset.

They also studied the data from the National Hurricane Center (for the North Atlantic and eastern-north Pacific basins) and data from the Joint Typhoon Warning Center (for the remaining ocean basins) and analysed 40-year (1981 to 2020) tropical cyclone intensity changes across all global ocean basins.

The team saw a significant surge in the frequency of multiple rapid intensifications across all ocean basins. The Western North Pacific Ocean basin contributed to nearly half of the total occurrences, while the North Indian Ocean basin had a comparatively low rate.

"Increased number of multiple rapid intensification tropical cyclones in the past 20 years compared to the penultimate period warrant improvement of existing numerical models, with crucial observations during the evolution of the tropical cyclones using new observational strategies such as drones and developing AI-based techniques for reducing uncertainties. Using these latest approaches, we hope to improve our understanding of the changing life cycle of tropical cyclones,” added Dr Sudheer Joseph, Scientist-G and Division Head of the Applied Research and Research to Operations (ARO) at INCOIS and corresponding author of the paper.

“Examining the variations in the intensification rates across time and at different stages of cyclone evolution will help us understand correctly when such events occur. More studies are needed to draw a relationship between the recent climate changes and triggering factors behind the rapid intensification of these cyclones." He said.

Dr. T. Srinivasa Kumar, Director, INCOIS added: “The findings of such studies will contribute to the knowledge base for understanding the impacts of future climate change on the behaviour of cyclones, which is one of the important elements in developing Ocean Climate Change Advisories by INCOIS under the Deep Ocean Mission.”