Chlorophyll (OLCI ~600m)
The sharpest daily colour composite, from the Sentinel-3 satellites. It only exists within about 108 nm of a coast, so blank open water is by design, and cloud holes are left empty.
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, from the OLCI camera on the Sentinel-3 satellites. Each pixel is about 600 meters across, a third of a nautical mile. It arrives about a day after the satellite pass.
Offshore, use Chlorophyll (GlobColour) or Chlorophyll (PACE, same-day).
A run of cloudy days gives a run of blank days.
Use it for fine detail near the coast, where Chlorophyll (GlobColour) can average away a color edge.
How it relates to the other chlorophyll layers. Chlorophyll (GlobColour) is the complete daily picture, with the cloud holes filled in by estimate. Chlorophyll (Sentinel-3, same-day) is a single pass from the same camera, sharper again and on the map the same afternoon. Chlorophyll (PACE, same-day) is another single pass, from a different satellite. 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 pass |
| How detailed it is | About 600 meters per pixel, a third of a nautical mile |
| Where it covers | Coastal only: within about 108 nautical miles of shore |
| How far back you can look | About 8 days; the provider keeps only a short archive |
| Goes blank under cloud? | Yes, often |
| Observed or modeled | Observed. Nothing is filled in |
| 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 the Sentinel-3 OLCI satellites.