WRF-based Assessment Of Wind Resource In A Complex Mountainous Area In Southwest China

With the development of society and economy,human’s demand for energy is increasing day by day.The widespread use of traditional energy will trigger energy crisis and environmental pollution.Wind energy has attracted more and more attention as a clean and renewable energy.Wind resource assessment is the premise and foundation of wind power development.There are three methods for carrying out wind resource assessment based on observation data from meteorological stations,observation data from wind towers and using numerical simulation software.Numerical simulation is more convenient and faster than the other two methods,with strong operability,saving manpower and material costs,and therefore more widely used.More than two-thirds of China’s land is mountain type,and the mountain wind field is complex.Accurate simulation of mountain wind field is the focus and difficulty of wind resource assessment.The mesoscale WRF model considers meteorological physical processes,and the simulation results are more comprehensive and reasonable.In this paper,the WRF model is used to perform high-resolution numerical simulation of a wind field in a complex mountainous area in southwest China.The main work and conclusions are as follows:(1)First,parametric comparative simulation tests were carried out on the 3km,1km and 333 m grid resolution WRF models to verify the WRF boundary layer,cumulus convection,land surface process,microphysical parameterization schemes and different grid resolution model pairs Impact of high-resolution wind field simulation of complex terrain.The results show that the boundary layer,cumulus convection,land surface process and microphysical parameter scheme have a greater influence on the WRF wind field simulation effect.Among the different resolution models,the 1km grid resolution model has the best comprehensive simulation effect.Due to the deviation between the simulated and measured wind speeds,this paper considers the wind speed uncertainty factors and uses the MCP(Measure-correlate-predict)method to correct the simulated wind speed and the standard deviation of the wind speed.This paper also considers the altitude difference between the wind tower and the WRF model grid,and extracts the corresponding simulated wind speed compared with the measured wind speed,The results show that the comparison effect is significantly improved,but the simulated wind speed at the position of the mountain top wind tower is still low,and the mountain top wind speed is underestimated.(2)Secondly,the WRF simulation of complex terrain wind fields has underestimated mountain top wind speeds and overestimated valley wind speeds.In response to this problem,this paper will consider the topo scheme of sub-grid orographic drag and apply it to WRF models with different resolutions,in order to verify its correction effect on complex mountainous simulated wind fields and its application to different resolution models.The results show that the Jimenez(topo1)scheme has a good correction effect on the low-level wind field of the 3km and 1km resolution models,but there is no obvious correction effect on the 333 m resolution model;The Mass(topo2)scheme does not show a significant correction effect on the wind fields of the three resolution models.At the same time,this paper introduces the turbulent orographic drag scheme proposed by Beljaars et al.Into the WRF model,and then corrects the simulation of the wind fields at various levels.The results show that the correction effect of the Beljaars scheme is obvious and can correct the wind fields at various vertical levels.,Improve the correlation coefficient,the root mean square error and other contrast parameters,provide a new idea for the simulation study of complex terrain wind field.(3)Finally,this paper applies the Weibull probability density parameter fitting to the wind field simulated by no Beljaars and Beljaars schemes,and calculates the wind power density distribution.The results show that the high wind speed areas such as ridges in this area are rich in wind resources and have good wind power development potential.