ISRO’s Oceansat-3 Detects El Nino’s Growing Impact on Pacific Ocean

India’s Oceansat-3 satellite has captured signs of changing conditions in the Pacific Ocean that are associated with the evolving El Nino in 2026. Observations from the Indian Space Research Organisation’s EOS-06, popularly known as Oceansat-3, show lower chlorophyll-a concentrations across parts of the Pacific during June 2026 compared with observations from the same month in earlier years.

The satellite data also indicates shifts in surface wind patterns, offering scientists a space-based view of how changes in the atmosphere and ocean are unfolding as El Nino develops.

Chlorophyll-a is a pigment found in phytoplankton, microscopic organisms that play a fundamental role in marine ecosystems. Because phytoplankton form the base of the ocean food chain, changes in chlorophyll-a levels can provide an indication of variations in biological activity and phytoplankton abundance.

Oceansat-3 observations show noticeable changes across sections of the central and eastern Pacific. Areas highlighted in the satellite data recorded lower chlorophyll-a concentrations in June 2026 when compared with patterns observed in June 2024 and June 2025.

These changes are significant because El Nino can disrupt the usual relationship between winds and ocean circulation across the Pacific. Under normal conditions, trade winds push warm surface water towards the western Pacific. This movement helps colder, nutrient-rich water rise from deeper layers in parts of the eastern Pacific, a process known as upwelling.

The nutrients brought to the surface by upwelling support phytoplankton growth. These microscopic organisms provide the foundation for marine food chains and contribute to sustaining fish populations and other ocean life.

During an El Nino event, changes or weakening in wind patterns can disturb this circulation. Warmer surface water can move into wider areas of the Pacific, while the upward movement of nutrient-rich deep water can be reduced. With fewer nutrients available near the surface, phytoplankton growth may decrease, resulting in lower chlorophyll-a concentrations.

Oceansat-3 provides an important way to observe these changes over a large area. The satellite is equipped to monitor ocean colour, surface winds and other characteristics of the marine environment, enabling scientists to study how large-scale climate events affect ocean conditions and ecosystems.

Comparing satellite observations from June 2024, June 2025 and June 2026 provides a visual indication of the changing conditions in the Pacific. The differences in chlorophyll-a levels and surface winds demonstrate how closely ocean ecosystems are connected to large-scale climate patterns.

The observations also highlight that El Nino is not solely an atmospheric event. Changes in wind and ocean circulation can have consequences for marine ecosystems, beginning with microscopic phytoplankton and potentially extending through wider food chains.

As the 2026 El Nino develops, continued observations from Oceansat-3 could help scientists monitor how its influence changes across the Pacific and better understand the relationship between climate patterns, ocean circulation and marine biological activity.