INCOIS to issue El Nino/La Nina outlook bulletins every month

Indian National Centre for Ocean Information Services (INCOIS) has come out with new products and services, including an El Nino/La Nina outlook and an improved version of regional ocean analysis, by assimilating sea level anomalies and a probabilistic storm surge prediction system.

Ministry of Earth Sciences (MoES) secretary M. Ravichandran had unveiled the new services earlier this month when he had chaired a meeting of the institute here. El Nino/La Nina bulletin is quite interesting since the ‘El Nino and Southern Oscillation (ENSO) has become one of the most important climate modes in the tropical region.

During the El Nino (warm) phase, the tropical central-eastern Pacific Ocean becomes anomalously warm and during the La Nina (cold) phase, it turns to anomalously cold. A reliable prediction is crucial for monitoring global climate patterns, regional monsoons and extreme weather events, explained director T. Srinivasa Kumar.

Dynamic and statistical models are generally used to predict these systems with the lead time for such predictions being limited to one or two seasons. INCOIS has developed a new method by blending the numerical models with an Artificial Intelligence (AI) /Machine Learning (ML) technique (Bayesian Neural Networks-BNN) to predict the evolution of the index of El Nino/La Nina with a lead time of 15-17 months.

This novel method will provide skilful predictions on the phase of ENSO well in advance and uncertainty in predictions with updated El Nino/La Nina outlooks on the fifth day of every month, he said.

The institute has also upgraded regional ocean analysis with sea level anomaly data assimilation and storm surge prediction. While short-term forecasts of ocean state were being issued for many years, it was found that the inclusion of the sea surface height anomaly data along with the temperature and salinity observations in the ocean significantly improved the quality of ocean circulation parameters such as currents, temperature etc. predicted by the numerical model.

In the new storm surge modelling system, several scenarios can be simulated by varying the intensity and track of the cyclones incrementally within the cone of uncertainty. From these scenarios, the probabilities for storm surges with different heights can be computed for the coastal regions.

This approach will help disaster management authorities to prepare better for mitigating the damages associated with cyclones by focusing on regions having a higher probability for storm surges, said group director and senior scientist T. M. Balakrishnan Nair.

INCOIS has also been issuing marine heat wave and coral bleach alert bulletins daily as they cause a threat to flora and fauna in the marine ecosystem and lead to the intensification of tropical cyclones and other weather extremes. This is for the benefit of stake-holders, including fisheries sector, tourism industry and policy makers.

“Marine ecosystem is threatened by changes in the partial carbon dioxide (pCO2) content too in the oceans and of late scientists have used ML to produce monthly mean maps of long-term averages of pCO2 concentration in the Bay of Bengal. The data is now made available to public through https://las.incois.gov.in,” he added.