Abstract: A performance evaluation is conducted for a state-of-the-art Coupled Model
Intercomparison Project Phase 6 (CMIP6)-derived ensemble of global wave climate simulations. A single-model (forcing), single-scenario approach is considered to build the ensemble, where the differentiating factor between each member is the wave model or physics parameterization used to
simulate waves. The 7-member ensemble is evaluated for the 1995-2014 historical period,
highlighting the impact of the multiple source terms on its robustness. The ensemble?s
ability to accurately represent the present wave climate is assessed through an
extensive comparison with long-term ERA5 reanalysis and in-situ observational data.
Relevant aspects such as the depiction of extremes and natural wave climate variability
are analyzed, and inter-member uncertainties are quantified. Overall, the results indicate
that the ensemble is able to accurately simulate the global wave climate, regarding
the significant wave height (???? ), mean and peak wave periods (???? and ????,
respectively) and mean wave direction (???? ??). However, we show that using multiple wave models
and parameterizations should be cautiously considered when building ensembles, even under
the same forcing conditions. Model- parameterization-induced ensemble spreads during the
historical period are found to be high, compromising the robustness of projecte
anges in wave parameters towards the end of the 21st century across several areas of the global ocean.