Study Of Costal Wind Simulation And Assessment Based On WRF Model And QuikSCAT/Windsat Data Assimilation In Zhoushan Islands

In this study, firstly, the wind resource in Zhoushan Islands in 2012 is simulated by WRF model, and the results are comparatively analyzed combining with observations from wind towers to select the optimal case for wind simulation there. Furthermore, two different satellite (QuikSCAT/Windsat) data are assimilated in WRF to simulate wind regime there with the optimal case in 2008, and the outcomes of unassimilated and assimilated simulation are compared with data of wind towers and stations. Finally, the best way is chosen to simulate wind, assess wind energy resource and wind power site in Zhoushan Islands.The results of wind simulation by WRF in Zhoushan Islands in 2012 show:1) WRF model can well reproduce the wind characteristics in terms of wind speed and direction time series, wind speed frequency, wind direction frequency, monthly average wind field and so on; 2) By analyzing five kinds of statistical parameters (RMSE, Bias, STDE, absolute error and relative error) and linear regression, it is found that the outcomes of simulation with Case2 have a significant correlation with observations in representative months (January, April, July and October) in aspect of time series, frequency distribution and wind field of wind speed and direction. Hence, Case2 is selected as the optimal assembled scheme for wind simulation in Zhoushan islands in the future; 3) Different errors between real atmosphere and simulations by different assemble schemes in terms of atmospheric stability may be the main reason to produce errors on simulation of wind regime at surface layer. Case2 plays a significant role in simulating the state of wind near surface because it can do better in simulation of atmospheric stability which is closed to actual atmosphere, while the other cases do worse than Case2 so that simulations with them cause large error.The comparative outcomes of wind simulation by WRF and QuikSCAT/Windsat satellite data assimilation in Zhoushan Islands in 2008 show:1) The simulative effects of WRF assimilating different satellite data are various, and it is not to obtain better results by assimilating all the satellite data than which has no assimilation; 2) In the first four days of different months, WRF assimilating QuikSCAT data can fully show better capability of wind simulation than other methods in comparison of the trend and overall distribution of time series of wind speed and direction, the linear regression test, absolute error, relative error of wind speed and RMSE of wind direction, which is able to present preferable effects that are more closed to observations. The effect of WRF unassimilated simulation takes second place, while it is better than which of Windsat data assimilation; 3) Using the monthly simulation results and comparing a variety of statistical parameter combining with distribution of average wind speed, SD, daily variation, wind rose, wind profile, wind shear index, maximum wind speed and its corresponding direction, Weibull distribution of wind speed, the simulative effects of WRF assimilating QuikSCAT are more coincide to the actual wind regime than which of having no assimilation, so WRF assimilating QuikSCAT data is more suitable for wind simulation and can be as a optimal method to assess wind resource and locate wind farm in Zhoushan Islands region; 4) The reason about advantages and disadvantages in wind simulations by three kinds of WRF model lies in the precision of initial data and incremental field. As QuikSCAT has higher precision than fnl and Windsat and also can produce detailed incremental fields which imply obvious power adjustment after assimilation by WRF, it makes the effectiveness which produced by assimilating QuikSCAT with the optimal case in WRF superior so as to help improve offshore wind simulation in Zhoushan Islands.The application of assessing wind energy resource of QuikSCAT data assimilation with the optimal case by WRF model in Zhoushan Islands show:1) Wind energy resource there is more rich, especially in Zhujiajian island which is in the south-east of Zhoushan Islands; 2) It is certain that the best installed direction of offshore wind farm in Zhujiajian island is S or N-NNE.