Sensitivity analysis of WRF model to physical parameterization for the characterization of coastal and offshore wind patterns in Caspian Sea region

Reliable estimations of wind speed and direction over water bodies are required for scientific and engineering applications. The optimum model parameters vary for different locations and conditions. In the present study, the Weather Research and Forecasting (WRF) model was employed to assess different parametrizations for the Caspian Sea region for warm and cold periods. All simulations were performed for nine different configurations for parameters related to the planetary boundary layer (PBL). Model evaluation was performed using synoptic station data, offshore buoy data, and Advanced Scatterometer (ASCAT) remote sensing data for two representative 10-day intervals in winter and summer periods. In the southern coasts of the South Caspian Sea (SCS), the Medium Range Forecast (MRF) PBL scheme performed best during winter, while the Total Energy-Mass Flux (TEMF) PBL scheme excelled in summer. The MRF PBL remains a suitable choice for year-round wind pattern simulation, except for the eastern Caspian Sea. In the eastern coasts, winter wind simulation performed well across configurations, but summer results were less favorable, with the Mellor-Yamada-Nakanishi-Niino (MYNN) and Asymmetric Convective Model 2 (ACM2) PBL schemes preferred for this season. In the western coast, the Yonsei University (YSU) PBL stood out in winter, while the Mellor-Yamada-Janjic (MYJ) PBL scheme was recommended for both cold and warm seasons. At the buoy station, the MYNN PBL scheme excelled in winter, while the MYJ PBL scheme performed best in summer, making it the preferred choice for year-round wind pattern simulation. The comparison with ASCAT data confirmed better model statistics during winter. The results also showed that model simulations were more accurate at the offshore buoy location than at coastal stations for all configurations.