The Man Who Teaches Computers to Read the Sky

The Interview

Prof. Vijay Natarajan, Department of Computer Science and Automation, Indian Institute of Science

Head of the Visualization and Graphics Lab, Humboldt Ambassador Scientist, and the quiet architect behind tools that track clouds, cyclones and ocean currents.

Prof. Vijay Natarajan does not work in the most obvious place for climate storytelling. He is not a meteorologist chasing storms in the field, nor a policy analyst parsing emissions targets. His craft is quieter, more structural: at the Indian Institute of Science, where he leads the Visualization and Graphics Lab, he builds the computational and geometric methods that help scientists see patterns in complex data. In a world where climate systems are increasingly difficult to understand, and increasingly urgent to understand well, that kind of work is indispensable.

His research has moved steadily from theoretical computer science into data visualization, topology, and applications that span biology, oceanography, and atmospheric science. In biology that has meant the geometry of channels in cell walls; in materials, the topology of sand as it jams; in climate, clouds and currents. What connects these domains is not subject matter but method. He is interested in the underlying shape of a problem: how to represent it, how to compute it, and how to make it visible enough for a scientist to ask better questions.

The Craft

Clouds are his proving ground.

Nowhere is that philosophy clearer than in his work on clouds. Clouds are deceptively difficult objects to define mathematically. They split, merge, disperse, and regroup. Rather than insisting on a rigid definition, the tracking framework his group built follows cloud clusters, collections of related pieces that move together as a system, and it was tested against events Indian readers will remember: the Mumbai deluge of July 2005 and Cyclone Aila in 2009. He later extended similar ideas to identifying and tracking cyclones, including the sprawling extra-tropical systems that carry enormous rainfall without the compact drama of a tropical storm.

The Weekend the Theory Got Real

Kerala, 1 and 2 August 2026.

On the first weekend of this August, the problem his mathematics describes arrived again, this time in Kerala. Bursts of extreme rain tore through the Western Ghats as flash floods and landslides; at least eight people died, eight went missing, and more than 5,700 moved into relief camps. The forecasts were not absent. IMD had warned of heavy to very heavy rainfall days in advance. What failed was resolution: a district-level alert cannot say which hillside, which hour.

Scientists at Cochin's Advanced Centre for Atmospheric Radar Research point to a warming Arabian Sea feeding mini-cloudbursts, concentrated cells that compress a season's violence into a few hours over a few square kilometres. These cells are exactly the objects that resist rigid definition, that split and merge and reorganise, that district-scale forecasting looks straight through. Kerala's gap between warning and event is two gaps stacked: radars fine enough to see the cells, and mathematics fast enough to find and follow them in the data. His tools have never issued a warning, and they were not built to. What his group has spent two decades building is the interpretation layer an operational early-warning system does not yet have. When The Climate Desk sat down with him, weeks before the floods, the Mumbai deluge was a validation case in an old paper. Kerala has made it a description of the operating environment.

The Ocean

Where Kerala's rain begins.

The conversation kept returning to the sea, because the ocean is where Kerala's rain begins. Working with oceanographer Prof. P. N. Vinayachandran of IISc's Centre for Atmospheric and Oceanic Sciences, Prof. Vijay has been studying salinity in the Bay of Bengal. The puzzle is simple to state and difficult to solve: despite enormous freshwater input from monsoon rains and rivers such as the Ganges and Brahmaputra, the Bay of Bengal remains broadly stable in salinity. The answer, their work suggests, lies in high-salinity water from the Arabian Sea moving through the Indian Ocean, carried by the summer monsoon current and shaped by eddies along the way. The stakes reach past oceanography: the Bay's salt balance sets how its waters layer, that layering governs how much heat the surface holds, and surface heat shapes monsoon rainfall and how quickly cyclones intensify.

The team extracted pathways through messy, dynamic data, tracing how that water travelled north and interacted with eddies en route. The methods now live inside pyParaOcean, an open-source visualization system built at IISc that oceanographers anywhere can use. The same warming basin that experts now link to Kerala's cloudbursts is the one his tools make legible. To be exact about the connection: his methods trace water within the sea, not moisture in the air above it. The link to Kerala is method, not mechanism, and it is stronger for being stated plainly. This is the heart of his contribution to climate science: he helps turn complex movement into visible structure.

The Humboldt Thread

Support people, not just projects.

None of this range was inevitable. A theoretical computer scientist does not drift into oceanography on his own; someone has to fund the wandering. For Prof. Vijay it was the Alexander von Humboldt Foundation, which, as he describes it, supports people rather than projects, and through them, science. His own fellowship opened the door to application-driven research and the cross-disciplinary collaborations that now define his lab, and fellows remain part of the network for life. That is why his role as a Humboldt ambassador fits: he now explains the people-first model to universities, students, and researchers, strengthening the Foundation's connection with India's academic ecosystem.

Bottom Line

Reading before responding.

There is a larger lesson in his story, and Kerala has underlined it in the hardest possible ink. Science advances not only by collecting better data, but by building better ways to interpret it. The hardware response is already moving: after the floods, Kerala's scientists called for high-resolution X-band weather radars, instruments that can see individual rain cells at kilometre scale, and IMD is commissioning one in Wayanad by December 2026, a decision set in motion by the 2024 landslide. These instruments will produce torrents of data. Whether they produce foresight depends on the quieter layer Prof. Vijay works in: the mathematics that finds the dangerous object inside the noise.

Before we can respond to the planet, we have to learn how to read it. And sometimes that begins with a rectangle, a curve, a path line, or a question we did not yet know how to ask.

A Climate Desk interview feature. Kerala figures as reported on 02.08.2026; Humboldt intake figures as published by the Foundation on 11.08.2026.