On May 14, 2021, the Arabian Sea was the battleground for one of the most powerful cyclones to date, known as Extremely Severe Cyclonic Storm (ESCS) Tauktae. This formidable storm wreaked havoc across India's western coast, leaving over 1.1 million people impacted and over 120 lives lost. A recent study has shed light on the complex interplay of oceanic and atmospheric conditions contributing to the intensity of Tauktae, highlighting the pressing need for refined cyclone forecasting as climate dynamics evolve.
The researchers focused their analysis on several key atmospheric conditions and ocean variables, including sea surface temperature (SST), relative humidity (RH), absolute vorticity (ABV), and the genesis potential index (GPI)—a metric used to assess the likelihood of cyclone formation and intensification. “Higher value of GPI (> 70) played a significant role in the intensification of ESCS Tauktae,” the authors stated, signifying the importance of these climatic drivers.
One of the primary findings indicated notable increases over the last decade, with SST rising above defined thresholds, particularly preceding Tauktae's formation, where it measured over 31 °C. Combined with RH exceeding 95%, these conditions provided ample heat and moisture—vital components for cyclone formation. “An active propagation of MJO before and during the cyclone led to provide high RH, and anomalous cyclonic circulation which increased the low-level relative vorticity of ESCS Tauktae for its genesis and intensification,” the authors noted, reflecting on the role of the MJO (Madden-Julian Oscillation) and its influence across the region.
Prior studies have documented the sensitivity of cyclones to oceanic factors, with Tauktae serving as evidence of significant climatological shifts. The past three decades have shown increased cyclonic activity, attributed significantly to warming of the Arabian Sea and its effect on atmospheric systems. The study used various methodologies, including regression analysis, combining satellite data and reanalysis products to assess how various factors impacted Tauktae's intensity and path. It elucidated the quantified roles the ocean and atmosphere had during the storm’s lifecycle.
Further revelations from the study indicated the contributions of atmosphere versus ocean to Tauktae's intensification were evenly balanced, with the atmosphere accounting for 53% and oceanic factors contributing 47%. “The atmosphere played marginally higher role than ocean for the intensification of ESCS Tauktae,” the authors concluded, asserting the significance of atmospheric perturbations alongside rising ocean temperatures.
The findings are particularly timely as global weather patterns are increasingly influenced by climate change, leading to more intense and frequent cyclones. The researchers emphasized the need for improved prediction systems, noting, “Quantified prevalent role of ocean and atmosphere for the intensification and sustenance of TCs is a major finding from the present study.” These insights not only aim to bolster cyclone forecasting but offer substantial contributions to climate adaptation strategies and disaster preparedness across vulnerable coastal regions.
Tauktae’s legacy continues to resonate, serving as both a stark warning about the forces of nature exacerbated by human-induced climate change and as an impetus for policy shifts aimed at disaster readiness. Understanding these variables can guide improvements for future infrastructure resilience and community safety as cyclones increasingly threaten regions like India’s western coast.