Correspondence of 0m elevation height of a digital elevation model (Copernicus DEM) to mean sea level

Question

I want to model future coastal flooding caused by sea-level rise under the latest IPCC scenarios at global scale. To this end, I use the Copernicus Digital Elevation Model (Copernicus DEM: https://spacedata.copernicus.eu/web/cscda/dataset-details?articleId=394198). I thought that the elevation height of 0m of the Copernicus DEM was the mean sea level of the data acquisition period of this DEM, but I have been told that it might not be the case.

Does the elevation height of 0m of the Copernicus DEM correspond to mean sea level of the ata acquisition period of this DEM (i.e., 2011-2015)?

Does it correspond to mean sea level of the vertical reference datum of this DEM (i.e., Earth Gravitational Model 2008 - EGM 2008) or does it correspond to an older historical reference?

In the Copernicus DEM metadata it is written:

Ocean water bodies are set to the elevation height of 0m, including all seas, inlets, fjords and any other extensions of the ocean.

I need to know what this 0m elevation height corresponds to and at what elevation is the mean sea level on this DEM.

Answer 1

Here is the answer given by the Support team of Copernicus:

The definition of the 0 m elevation for ocean areas is not dependent on the acquisition date of the input images. Please note that the Copernicus DEM is quality-based combination of multiple acquisitions which, from our understanding, prevents to focus on just a single scene and the ocean extent present at that day. Elevation 0m in the Copernicus DEM is more general and referring to the mean sea level of the vertical reference datum of this DEM (i.e., Earth Gravitational Model 2008 - EGM 2008).