ISRO Tracks El Niño: Oceansat-3 Reveals Changes in Pacific Winds and Marine Productivity

The oceans play a central role in Earth’s climate system, influencing weather patterns, rainfall, marine ecosystems and millions of livelihoods. Recent observations by the Indian Space Research Organisation (ISRO) demonstrate how satellite technology can help scientists monitor subtle changes occurring across vast stretches of the world’s oceans.

ISRO’s EOS-06 satellite, also known as Oceansat-3, has been monitoring changes associated with El Niño in the equatorial Pacific. The observations include variations in surface winds and ocean productivity, two important indicators of changes taking place during the development of this major climate phenomenon.

What Is El Niño?

El Niño occurs when the central and eastern tropical Pacific Ocean becomes unusually warm. This warming can disturb normal atmospheric and oceanic circulation patterns.

Under normal conditions, Pacific trade winds help push warm surface water towards the western Pacific. During El Niño, these winds can weaken or change, allowing warm water and accumulated heat to redistribute across the Pacific.

Such changes can affect ocean temperatures, nutrient movement and atmospheric circulation. The resulting effects can extend far beyond the Pacific and influence weather conditions in other parts of the world.

Oceansat-3 Monitors Changes in Ocean Productivity

One of the important indicators observed by Oceansat-3 is chlorophyll-a, a pigment associated with phytoplankton.

Phytoplankton are microscopic marine organisms that form the foundation of the ocean food chain. Their abundance is therefore an important indicator of marine productivity and the health of ocean ecosystems.

Satellite observations during the developing El Niño have indicated a decline in surface chlorophyll-a in parts of the equatorial Pacific. One possible explanation is reduced upwelling, which limits the movement of nutrient-rich deep water towards the surface.

Changes in Pacific Winds Can Affect Marine Ecosystems

Changes in surface winds are another important factor. When the normal Pacific trade winds weaken or change direction, ocean currents and the movement of nutrients can also be affected.

Reduced nutrient availability can decrease marine productivity and potentially influence fish populations and other organisms that depend on phytoplankton.

This makes satellite-based monitoring important not only for climate science but also for understanding changes that may affect marine ecosystems and fisheries.

Why El Niño Matters for India

Although El Niño develops in the Pacific Ocean, its influence can extend across oceans and continents. The atmosphere and oceans operate as an interconnected system, meaning disturbances in one region can influence weather patterns elsewhere.

For India, understanding these connections is particularly important because El Niño can influence the behaviour of the Indian monsoon. However, the relationship is not identical during every El Niño event, and other climatic factors can also affect monsoon conditions.

Better monitoring can therefore contribute to seasonal climate forecasts and help improve planning for agriculture, fisheries and coastal communities.

Oceansat-3 Provides a Wider View From Space

One of the major advantages of Oceansat-3 is its ability to repeatedly observe large areas of the ocean from space.

Ships, buoys and other instruments provide valuable observations from specific locations, but satellites can offer a much broader picture. Continuous satellite observations can help scientists identify developing patterns and study changes across large ocean regions.

India’s Space Programme and Climate Research

The growing use of satellites for environmental monitoring highlights the expanding role of India’s space programme in climate and Earth-system research.

Satellite data can support studies related to climate variability, ocean health, disaster preparedness and natural-resource management. Such information can also help researchers better understand the relationship between ocean conditions, atmospheric changes and economic activities.

Better Monitoring Can Improve Preparedness

Continued observations of the Pacific and other ocean regions can help scientists improve their understanding of El Niño and its wider effects.

For India, better climate information can support decision-making in agriculture, fisheries, coastal management and disaster preparedness. It can also contribute to early-warning systems and help communities prepare for changing environmental conditions.

By observing the oceans from space, ISRO’s satellite programme is providing valuable data for studying how distant climate events can influence regional weather and ecosystems. Continued monitoring will remain important for improving forecasts and understanding the links between ocean health, climate variability and economic security.