Chlorophyll (GlobColour)
How green the water is, merged from several satellites into one daily picture. The most complete colour layer we carry — but the cloud holes are filled in by estimate, not observed.
Updates daily
More detail
This layer shows chlorophyll, the green pigment in plankton, at the surface. Low numbers are clear blue water, and high numbers are green water. It is made by the Copernicus Marine Service, the European Union's ocean data service, which calls it GlobColour, from five satellites. It runs about a day behind the satellite passes.
The estimates are weaker than a real look, and the map does not show which parts are estimates. The biggest holes are left empty. The layer covers the Gulf of America, the East Coast and Baja.
Use it to find where green water meets blue when you want the whole picture. Be careful with a sharp edge that sits under several days of cloud.
How it relates to the other chlorophyll layers. Chlorophyll (OLCI ~600m) is a sharper next-day picture that exists only within about 108 nautical miles of a coast and leaves cloud blank. Chlorophyll (PACE, same-day) and Chlorophyll (Sentinel-3, same-day) are single satellite passes, on the map the same afternoon, with cloud left blank. Use Chlorophyll (GlobColour) for a complete picture, Chlorophyll (OLCI ~600m) for a sharp look near the coast, and the two same-day layers to see only what was seen today. The four do not agree exactly. All four share one color scale. Chlorophyll Concentration is a computer model's estimate, not a satellite picture, and will not match them.
The provider keeps about the last 8 days. The first version of each day is replaced with a corrected one within about a month, so an older date may not look the way it did.
The numbers
| How often it updates | Once a day, one frame per day |
| How fresh it usually is | About 1 day behind the satellite passes |
| How detailed it is | About 2.2 nautical miles (4 km) per pixel |
| Where it covers | Gulf of America, East Coast and Baja |
| How far back you can look | About 8 days; the provider keeps only a short archive |
| Goes blank under cloud? | Rarely. Cloud holes are filled in by estimate, though the largest holes stay empty |
| Observed or modeled | Observed, then filled |
| What you see on screen | mg/m^3, the amount of chlorophyll in the water. The default color range is 0.03 to 1.0. Surface only |
Source: a satellite picture from GlobColour, merged from several ocean-color satellites (Copernicus); cloud holes filled by estimate.