Ocean Chlorophyll-a — worldwide satellite map

An interactive world map of ocean chlorophyll-a (phytoplankton) concentration from NASA ocean-color satellites — MODIS Aqua, VIIRS and PACE. View any day from 2002 to the present, build weekly or monthly cloud-free averages, and compare two dates side by side as a difference map. Useful for exploring phytoplankton blooms, ocean productivity, upwelling, and El Niño / La Niña effects on the ocean.

Ocean Data Explorer

Worldwide · NASA & NOAA ocean satellites
Color scale
Click anywhere on the map to read the value at that point.
Credits & methods

Data sources. We acknowledge the use of imagery provided by NASA's Global Imagery Browse Services (GIBS), part of NASA's Earth Science Data and Information System (ESDIS): chlorophyll-a (MODIS-Aqua, VIIRS NOAA-20/SNPP, PACE OCI; processed by the NASA Ocean Biology Processing Group, OB.DAAC) and GHRSST MUR sea-surface-temperature. Basemap, coastlines and labels: NASA GIBS. Coral Reef Watch products — SST, SST anomaly, Degree Heating Weeks and Bleaching Alert Area — from NOAA Coral Reef Watch (5 km, 1985–present), served via the PacIOOS ERDDAP.

Averaging & differences. For NASA imagery layers, weekly/monthly averages and date-to-date differences are computed in your browser by decoding each pixel from the fixed colour scale — chlorophyll as a geometric mean / log-ratio, SST as a mean / °C difference. These are derived from colour-coded tiles, not source data values.

Trends. Clicking a point charts a time series there. Chlorophyll trends use gap-filled VIIRS Science-Quality Level-3 data (NOAA CoastWatch, 4 km); Coral Reef Watch trends use NOAA CRW gridded values (via PacIOOS); SST trends are sampled from the map tiles. The marker value reflects the displayed imagery at the selected date.

Limitations. Intended for visualization and education — not quantitative or navigational use. For research-grade values use NASA Giovanni, NASA Ocean Color, or NOAA Coral Reef Watch directly.

Map library: Leaflet. This site is not affiliated with or endorsed by NASA, NOAA, or PacIOOS.