Ocean surface wind simulation forced by different reanalyses: comparison with observed data along the Iberian Peninsula coast

Abstract

The performance of the Weather Research and Forecast (WRF) mesoscale model in the ocean surface wind simulation was assessed and evaluated under different initial and boundary forcing conditions. Due to the continuous evolution and progress in the development of reanalyses datasets, this work aims to compare different WRF forcings through reanalyses datasets that are currently kept up to date in near real-time. These datasets consists of the first generation reanalysis NCEP-R2 and two recently released reanalysis datasets that represent the new generation of this type of data (ERA-Interim and NCEP-CFSR). These three reanalyses datasets were used as initial and boundary conditions for the WRF model to simulate surface oceanic wind simulations offshore of the Iberian Peninsula region (more specifically, on the Galician coast and the Gulf of Cádiz). The results are compared with observed wind data from five buoys that measure the wind in the selected region, with the objective of determining which of the three reanalyses produces more accurate wind simulations. The results show that simulations driven with ERA-Interim reanalysis present lower errors when compared to measured winds. This approach provides the most realistic initial and boundary data that can generate ocean wind simulations closest to real winds, although the NCEP-CFSR simulation results are very similar to those obtained with ERA-Interim. The NCEP-R2 reanalysis showed higher errors when compared to the new generation reanalyses. Based on the analysis and results presented in this work, it can be concluded that, for the area under study, the new generation reanalyses are considerably better for ocean wind simulations than the older reanalyses. This is in agreement with the improvement of the models, measurements and data assimilation that are used in the building of the reanalysis datasets. The higher spatial resolutions, the larger amount of assimilated measured data and the improvements of the data assimilation and correction techniques of ERA-Interim and NCEP-CFSR reanalyses data allow for a more accurate and realistic representation of the local wind climate.