Evaluation of the Wind Speed and Wave Heights Simulation in the Kara Sea Using the COSMO-CLM and WAVEWATCH III Models

Purpose. The work is aimed to obtain the quality estimates of the results of modeling the wind speed and wave heights in the Kara Sea. Methods and Results. The COSMO-CLM model was used to simulate the atmospheric conditions, and the WAVEWATCH III model – to obtain the wave parameters with high resolution in the coastal zone. Eight COSMO-CLM-based numerical experiments including various model options and grid sizes from 12 to 2.8 km were carried out for the periods September – October, 2012 and August – September, 2014. To assess the quality of wind speed and wave height modeling, the data of the CryoSat and SARAL satellites, as well as the coastal weather stations were used. Statistical indicators for assessing the quality of wind and wave reproduction for different model configurations were obtained. The wind speed assessing was best provided by the COSMO-CLM model configuration with the ~ 12 km resolution in the basic domain and the ~ 3 km resolution in the nested one; at that in both cases the “spectral nudging” technology was used. Verification using the weather stations data and the satellite measurements performed for the model optimal configuration, has shown that for the wind speed, the average correlation coefficients were ~ 0.8, the bias varied from 0.1 to 0.4 m/s, and the RMS error was 1.7–1.8 m/s. As for the wave height assessments, the best result was obtained when the wind fields with the 3 and 10 km resolutions were applied (the RMS error was ~ 0.4 m and the correlation coefficient was ~ 0.87). Conclusions. It is shown that in all the cases, application of the “spectral nudging” technology improves quality of the wind speed and wave height modeling performed due to the COSMO-CLM – WW3 system for the Kara Sea region. Quality of the results of wind field reproduction using the COSMO-CLM model with the ~ 3 km resolution is comparable to quality of the ERA5 and CFSv2 reanalyses. Since mesoscale modeling provides a more detailed wind field spatial structure, especially in the coastal regions, the results permit to use the wind fields with the 3 km resolution for a wide range of scientific and applied tasks.