Assessment of a wind map over the Korean Peninsula based on WRF-FDDA

Abstract

Wind map with a high resolution needs to encourage wind energy industry and assessment of wind resource. Wind speed above 50m above ground level (AGL) is important for wind energy, but it is difficult for us to obtain observed wind speed information above 50m AGL. Therefore, it is necessary to use mesoscale or microscale numerical model and we establish wind map using numerical model over the Korean Peninsula. The model which is used in this study is Weather Research and Forecasting (WRF) that is developed in NCAR. A high resolution topography with a 100-m resolution and a land-use data which has a 30-m resolution are implemented over the Korean environment for the improvement of surface layer wind forecast in WRF. WRF-FDDA (Four-Dimensional Data Assimilation) has conducted with a 1 km resolution which is forecasted using NCEP FNL data employed as initial and boundary condition. Surface and upper observations are ingested in WRF-FDDA to improve initial condition by regional observation. The WRF model has run for one year for the wind map over the South Korea. The running periods that is named as typical meteorological year (TMY) is determined by statistical method. The TMY represents mean atmospheric characteristics from 1998 to 2009. Strong wind occurs in eastern, southern coastal region, and Jeju island of Korea. Wind in the Korean Peninsula blows from northwest during most of the season, but from southeast during summer. High occurrence rate of main wind direction is shown in mountainous region of inland and coastal region. The results of wind map study help indentify locations of with highest wind energy potential in the Korean Peninsula. The performance of the TMY results over the South Korea is validated with surface and radiosonde observation at 10m and 80m above ground level. Root-mean-square-error (RMSE) shows about 2-3 m/s and 3-4 m/s for wind speed at 10m and 80m, respectively and mean absolute error is about 30-50 degree for wind direction. Validation results indicate that accuracy of wind map decreases over the mountainous region such as eastern coastal region of the Korea. Although the simulation with a 1 km horizontal resolution indicates high resolution, it is limited to resolve over complex mountainous region. The model performance shows that the error increased in the mountainous region. Therefore, we conducted the simulation using WRF-LES with a 333-m horizontal resolution over the complex terrain. WRF-LES results would be presented in the conference.