| Summary: | 碩士 === 國立臺灣大學 === 環境工程學研究所 === 99 === In this work, objective analysis is the first step to Establish 3-D wind field in Taiwan. Initial wind field, which is generated by objective analysis, affect the result of final wind field seriously. To reduce the error, we improved the weighting function of objective analysis used in the past and cause the grid point’s simulation value is more in line with the observation value. The weighting function used in the past does not take into account the density of stations in an aera. A variable radius of influence is used in this stuy.We used a small radius of influence in a high density of stations aera and a large radius of influence in a small density of stations aera.In addition, each grid point is interpolated by the nearest stations. The result of using variable radius of influence obtained a better wind field, the average wind speed error between simulation and observation could be less than 0.5m/s and the minium wind speed error could be 0.16m/s. The wind speed correlation is above 0.9.
Moreover, NCEP reanalysis data, which is provided by U.S. Oceanic and Atmospheric Administration Center, was added in our simulation to replace the extrapolate method used in past. Each virtual station’s data is interpolated by NCEP reanalysis data. The results show that by using NCEP reanalysis data as the boundary of domain obtain more reasonable wind field.
|
|---|
