An international study led by the Indian Institute of Technology Madras (IIT Madras) found that accounting for aerosols, tiny particles suspended in the air, greatly improves simulations of extreme rainfall and the urban flooding it causes. The work was published in Natural Hazards and Earth System Sciences and announced by the institute on 5 October 2026.
The team used Chennai’s extreme rainfall and floods of December 2015 as a case study. It added aerosols and the particles on which cloud droplets form to a high-resolution weather model, then fed the simulated rain into hydrological and flood models of the Adyar river basin.
The result was an improvement of about 22% in simulated rainfall over the basin and about 50% in the accuracy of the flooded area, compared with the simulation without aerosols. Germany’s GFZ geosciences centre, the Japan Aerospace Exploration Agency (JAXA) and Kathmandu University in Nepal also took part.
The authors stress that the method is not yet an operational forecasting system. It needs testing on other storms and cities, better aerosol measurements and faster calculations. If that is achieved, it could help decide in time when to store or release water from reservoirs during heavy rain.
