ISRO Satellite Captures El Nino's Impact on Pacific Ocean Marine Productivity

India's EOS-06/Oceansat-3 satellite has captured clear signs of the developing El Nino and its impact on marine productivity across the tropical Pacific Ocean, according to an analysis by ISRO's National Remote Sensing Centre (NRSC). The analysis, using data from the satellite's Ocean Colour Monitor-3 (OCM-3) and its Scatterometer, found a marked decline in surface chlorophyll-a concentration during June 2026 compared with neutral years of the El Nino-Southern Oscillation (ENSO), the periodic warming and cooling pattern in the Pacific. Chlorophyll-a is a key indicator of phytoplankton abundance and marine productivity.

The decline coincided with a shift in ocean-surface winds, ISRO said: the region's usual easterly winds weakened and reversed to westerlies, disrupting the normal equatorial upwelling that brings nutrient-rich water from the depths to the surface. Satellite observations showed the region of elevated chlorophyll-a progressively contracting westward between April and June 2026, further evidence of weakening upwelling as El Nino developed.

ISRO said the combined OCM-3 and Scatterometer observations demonstrate strong coupling between atmospheric winds and biological processes in the equatorial Pacific. If El Nino intensifies further, as forecast, the low-chlorophyll region could become increasingly pronounced.

The satellite findings complement the World Meteorological Organization's outlook, which had estimated an 80% probability of El Nino conditions developing during June-August 2026. By late July, the WMO reported the event was intensifying and was expected to strengthen further during August-October.