INCOIS testing new high-resolution system coastal hazard forecasting

The Indian National Centre for Ocean Information Services (INCOIS), which houses the Indian Tsunami Early Warning Centre and provides ocean state forecast advisories, is currently testing an advanced Indian Ocean-Land-Atmosphere (IOLA) Coupled Mesoscale Prediction System which is expected to help the institute as well as the IMD for more accurate forecasting of rainfall, inland severe weather, and coastal hazards.

“There is a demand from oil companies and the Coast Guard for higher resolution, high accuracy forecasts for their areas of interest. Once fully operational, the new system will enable us to produce continuous higher resolution forecasts,” said senior scientist Sudheer Joseph.

The IOLA system aims to create a uniform framework for simulating severe weather, including ocean currents and other small and large scale coastal phenomena. It incorporates advanced modelling and nesting techniques from the Hurricane Weather Research and Forecast System (HWRF), currently in operational use of IMD, he explained.

Dr. Joseph is leading the research team along with scientists from institutions such as NIT Rourkela, IIT Bhubaneswar, Atlantic Oceanographic and Metrological Laboratory, University of Texas at Austin (US), and the Indian Meteorological Department (IMD).

The proposed system will be unique in its ability to generate location-specific ocean forecasts by leveraging high-resolution atmospheric forcing for ocean models, satellite-data, offshore platforms such as Argo floats. “It can simulate extreme weather systems including those beyond just storms using 1.2 km resolution nested models. This significantly enhances prediction skill for rainfall, ocean currents, and precise ocean state conditions,” said Dr. Joseph.

Highlighting the vulnerability of the Indian coastline to tropical cyclones, monsoon rainfall, and coastal hazards, he noted that thunderstorms and lightning alone account for nearly 350 fatalities every monsoon. While the existing global models cannot be fine-tuned for accurate prediction of such localised events, the existing HWRF can track only one storm at a time, he said.

Coastal forecasting remains particularly challenging due to rapid changes in land-sea breezes, tidal surges, and bottom friction in shallow waters, which influence ocean surface roughness. Dr. Joseph emphasized that the upcoming forecasting system is essential for offshore industries. “Any sudden change in ocean current direction or speed can drastically impact offshore drilling and off-loading activities. An improved forecasting will help authorities plan mitigation measures including halting certain operations well in advance,” he said.

Expected to become operational after proper validation within a year, the IOLA system will also support detailed analysis of India’s coastline and enable high-precision forecasts for the Lakshadweep Islands and Andaman & Nicobar Islands using high-resolution nests.

“We currently use low-resolution models, which suit large countries like India with long coastlines. But for island nations like the Maldives, where the total size is around six kilometres smaller than a single grid point, a high-resolution variability will be a major advantage,” he added.