Aerodynamic roughness comparison between the estimated based on masts and the defined in model over Xinjiang wind areas
Based on the data from 17 wind masts over Xinjiang wind areas,the aerodynamic roughness lengths extending some ranges are estimated using the standard deviations of wind speed and direction.Then the estimated roughness lengths in the target areas are compared with those defined in numerical model MM5 or WRF or CALMET on account of 3 km and 1 km horizontal resolutions,respectively.Results are as follows:In most of the cases,the defined roughness lengths are moderately consistent with the estimated ones while few of them show major discrepancies due to a misinterpretation of landuse dataset.Thus further emphasis should be on modifying these datasets.The calculated roughness lengths in the strong wind areas are uniformly smaller than the defined roughness in meso-scale model in summer.To attain a better accuracy in cases where the roughness in primary and secondary wind directions is severly nonhomogeneous,the two methods of wind speed and direction standard deviations should be combined.In this study,the roughness lengths are estimated with the samples in neutral atmosphere while they will not be the applicable in areas where neutral atmosphere barely occurs.
Xinjiang wind areasunderlying surfaceestimated dynamic roughness lengthstheoretically defined dynamic roughness lengths in MM5/WRF/CALMET models