The MODIS (Moderate Resolution Imaging Spectro-radiometer) sensor was deployed onboard the NASA Aqua satellite. It is a multi-disciplinary sensor providing data for the ocean, land, aerosol, and cloud research and is used for detecting chlorophyll-a concentrations in the world's oceans, among other applications. Aqua MODIS views the entire Earth's surface every 2 days, acquiring data in 36 spectral bands. The data available here are the latest reprocessing from June 2015, which NASA undertook to correct for some sensor drift issues.
Through detection of phytoplankton, chlorophyll-a concentration provides a measure of biological activity. Phytoplankton are microscopic, free-floating photosynthetic organisms that form the basis for most of the ocean's food chain and play an important role in the global carbon cycle by removing carbon dioxide (CO2) from the atmosphere during photosynthesis.
dates available: 2002 - present
spatial resolution: 0.05° (~4 km)
data archive: https://oceanwatch.pifsc.noaa.gov/doc.html#chl