SOURCE: PIB
Data from the EOS-06 (Oceansat-3) satellite enables the monitoring of the dynamics of the Global Biosphere on Land & Oceans every month. Launched in November 2022, EOS-06 is the third-generation satellite in the Oceansat series, equipped with the Ocean Colour Monitor (OCM-3) and a Scatterometer (SCAT-3) sensor. OCM-3, featuring 13 spectral bands (in the 412-1010 nm spectral range), captures the global vegetation condition/greenness on land by measuring the Normalized Difference Vegetation Index (NDVI) and ocean biological productivity over oceanic regions by measuring phytoplankton Chlorophyll concentration.
The SCAT-3 sensor provides high-resolution global ocean surface wind speed and direction information. Data from both these sensors are valuable for studying global land vegetation, ocean biogeochemical dynamics, ocean circulation, and cyclogenesis across the globe. EOS-06 provides the unique advantage of simultaneously providing NDVI, ocean chlorophyll, and winds, depicting the ocean upwelling zones, movement of chlorophyll blooms, and trends in global land vegetation in different months.
Monthly datasets from these sensors were analyzed at the National Remote Sensing Centre (NRSC)/ISRO, Hyderabad. Global monthly animations of NDVI, Chlorophyll, and Ocean wind vectors are generated at a 4 km grid resolution. The animation below illustrates the evolution of ocean chlorophyll (in color) superimposed with ocean surface wind vectors and NDVI over the continents (in color) from April to December 2023. The land NDVI depicts the greening and browning of continents in different months. The northern latitudes show the evolution of green cover from winter to summer months in the northern hemisphere.
From these studies, scientists infer that high-productivity oceanic regions are found in the extratropical oceanic, equatorial, and coastal upwelling zones located on the west coast of major continents such as the Indian subcontinents, South America, Africa, etc. Enhanced concentrations of Chlorophyll-a, depicting phytoplankton blooms, occur during October-December in response to wind-driven circulation. Vector winds show dominant circulation features such as convergence of tropical easterlies in the near-equatorial region, mid-latitude westerlies, and seasonally reversing monsoon winds in the Indian Ocean.