ERA Interim problem with Waves Has anyone had a problem with significant wave height (swh) and mean wave period (mwp) from ERA-Interim not matching very well with either a time series of measurements or a different model? Or does anyone know if the formulas in the model (the way they made it) have changed from one period to another? (In my case they seem to correlate better/worse at either side of 1991).
I haven't looked into ERA-Interim wave data a huge amount but I know around 1991 it started to assimilate ocean wave data from satellite altimeters (ERS-1).
See the first figure here
https://climatedataguide.ucar.edu/climate-data/era-interim

I remember Jean-Raymond Bidlot who runs WAM at ECWMF showing me so experiments with and without the assimilation into the wave. I think the Hs differed by ~1m in large events so not insignificant.