Evaluation of ERA5 Significant Wave Height versus New Multi-Mission Satellite Altimeter Measurements in an Enclosed Basin

The present study aims to examine the accuracy of significant wave height (Hs) based on the ECMWF (European Center for Medium-Range Weather Forecasts) ERA5. The ERA5 reanalysis datasets are retrieved for the period 2002−2021, having spatial and temporal resolutions of 0.50  0.50 and 1 hour, respectively. The ERA5 Hs datasets are validated versus in-situ measurements. The ERA5 reanalysis datasets are reasonably well matched at four measurement stations, as indicated by a relatively high correlation coefficient (r, Q-Q plot) and low statistical error measures (bias, NBI, SI, and RMSE). The results indicate that the ERA5 datasets perform well in estimating Hs in the Black Sea. The ERA5 Hs is used for the spatial validation of the data from the European Space Agency for Sea State Climate Change Initiative (ESA CCI-SS). The ESA CCI-SS, a new multi-mission satellite altimeter measurement of the Hs datasets, provides the data with a 1.0  1.0 spatial resolution and monthly temporal resolution, spanning from 2002 to 2021. It has been determined that ESA CCI-SS (v3, latest version) datasets from the multi-mission altimeter measurements are in good agreement with the ERA5 reanalysis data over the entire Black Sea. The results of the long-term (20-year average) and monthly averages exhibit that the ESA CCI-SS datasets are a good alternative data source in terms of Hs and can be reliably used for the Hs in the Black Sea wave climate studies.