Copernicus Marine Layers

The Copernicus Marine Service publishes the ocean products of the European Union's Copernicus programme: temperature, salinity, currents, sea level, waves, sea ice, chlorophyll and more, as satellite observations and as model analyses and forecasts. Its MyOcean viewer draws them from a public tile service that any map can read. The basemap library carries four of its layers as overlays. This page records how the service works, why the library stops at four, and how to add another by hand.

The four overlaysCopy Anchor Link

They sit in the basemap Library, as overlays that stack over the active basemap.

Each one is requested without a date, so the server draws its default: today for the forecasts, the latest analysis for the temperature, the latest complete month for the chlorophyll. The tiles are transparent over land.

The data is coarse next to a terrain model. The tile grid stops at zoom 10. The chlorophyll, at 300 m, holds up along a coast; the other three, at 5 to 8 km, are for basin-scale context.

Why only fourCopy Anchor Link

The service lists 10 051 layers (November 2026). Each product has several datasets, one per time step and version, and each dataset has several variables, plus an uncertainty layer for most of them. Listing them all would bury the rest of the library, so the selection is by hand: one layer for each of the four questions people ask most.

The tile serviceCopy Anchor Link

The service is WMTS, at https://wmts.marine.copernicus.eu/teroWmts. It answers with an open Access-Control-Allow-Origin: * header and needs no key or account. There is no WMS: Copernicus Marine retired it in favour of WMTS.

Layer names have three parts, PRODUCT/dataset/variable:

GLOBAL_ANALYSISFORECAST_PHY_001_024/cmems_mod_glo_phy_anfc_0.083deg_P1D-m_202406/siconc

The dataset name ends with a version stamp, here 202406. When Copernicus re-versions a dataset the stamp changes and the old layer name stops answering. That is the one way these overlays can go stale, and the fix is to look the new name up in the capabilities.

Tile grids. Every layer comes in EPSG:3857 and EPSG:4326, each also at @2x and @3x pixel density, from zoom 0 to 10. The Web Mercator grid matches the map's own, so a layer works as a plain tile template:

https://wmts.marine.copernicus.eu/teroWmts?SERVICE=WMTS&REQUEST=GetTile&VERSION=1.0.0
  &FORMAT=image/png&TILEMATRIXSET=EPSG:3857
  &TILEMATRIX={z}&TILEROW={y}&TILECOL={x}
  &LAYER=<PRODUCT/dataset/variable>&STYLE=<style>

Styles are a colour map and options, joined by commas: cmap:thermal, cmap:algae,logScale. Each layer lists its own in the capabilities, a default map chosen for the variable plus its log-scale twin. Vector variables such as currents add vectorStyle:solid, vectorStyle:vector or vectorStyle:solidAndVector for colour, arrows or both.

Dimensions. Every layer has a time dimension, given as a start, an end and a step, for instance one day from 2022-06-01 to nine days ahead for the physics forecast. Layers with depth add elevation, in metres below the surface as negative numbers. Both are plain query parameters, &time=2026-10-28T00:00:00Z&elevation=-100, and both fall back to a default when left out: the latest step and the level nearest the surface.

CapabilitiesCopy Anchor Link

The full capabilities document is about 70 MB, far too large to load in a browser:

https://wmts.marine.copernicus.eu/teroWmts?SERVICE=WMTS&REQUEST=GetCapabilities

One product's capabilities are small, 380 KB for the global physics forecast, and list its layers, styles and dimensions:

https://wmts.marine.copernicus.eu/teroWmts/GLOBAL_ANALYSISFORECAST_PHY_001_024?SERVICE=WMTS&REQUEST=GetCapabilities

The product id is the one in the address of the product's page in the Copernicus Marine catalogue.

Adding another layer by handCopy Anchor Link

1. Find the product in the catalogue and note its id.
2. Open that product's capabilities, and pick a layer identifier and one of its styles.
3. In the app, add a custom basemap of type TMS/XYZ (Raster Tile) with the tile template above, the layer and the style filled in. Pick the Overlay role to stack it over the basemap, and set the maximum zoom to 10.
4. For a past day or a depth, append &time= and &elevation= to the template.

CaveatsCopy Anchor Link

• Daily satellite chlorophyll does not hold. The 4 km gap-free daily product answered its default day and the two days before with an error in November 2026, and it keeps a rolling window of ten days only, so a fixed date a week back works for a few days and then leaves the window. This is why the library's chlorophyll is the monthly 300 m mean, which lists a single month, the latest complete one, and always answers. For a daily and current chlorophyll, the model is the layer that holds: GLOBAL_ANALYSISFORECAST_BGC_001_028/cmems_mod_glo_bgc-pft_anfc_0.25deg_P1D-m_202311/chl, at 0.25°.
• No timeline yet. The overlays show one day. The time dimension would fit the historical timeline, a tick per step, and a catalogue picker could load one product's capabilities on demand. Neither is built.
• Projection. The service draws Web Mercator tiles itself, so nothing is reprojected in the browser. The polar oceans stretch as on any Web Mercator map.

LicenceCopy Anchor Link

Copernicus Marine products are free and open, for any use. The service asks for the credit "Generated using E.U. Copernicus Marine Service Information" and, in a publication, for the product's DOI, which each product page gives.