Mesoscale modelling in China: Risø DTU numerical wind atlas calculation for NE China (Dongbei)

摘要

This document reports on the methods and findings of project “A01 Mesoscale Modelling”, part of the CMA component of the Wind Energy Development (WED) programme, focusing mainly on the methods and work undertaken by Risø DTU. The KAMM/WAsP methodology for numerical wind atlas calculation of the wind resource for Dongbei south of 50oN. The results of the numerical wind atlas show a wind resource over the region of interest modulated mainly by topographic features. These are principally elevated terrain features, giving high resources on exposed ridges and lower resources adjacent to the low slopes of mountains and large-scale valley features. A comprehensive verification was carried in which the generalized wind climates derived from mesoscale modelling and measurements for nine meteorological stations were compared. A mean absolute error of 8 % for 50 m wind speeds was determined. The major new aspects of the project were the large number of KAMM/WAsP sensitivity studies, comparison with WRF, and the CMA’s numerical wind atlas method (WERAS). Additionally, the reliability of the input data for the methodology, and the wave-number spectra properties of the output data were investigated. Comparison and verification of the results of CMA’s numerical wind atlas method (WERAS) were carried out. Generalized wind climates show a positive bias compares to measurement, though an improved generalization method is thought will improve this result. A more direct comparison was made between KAMM and WRF by using KAMM wind classes in WRF, run in idealized mode. A smoother resource map was given by WRF and different gap flow behaviour was noted. Future work would be well directed towards i. improving the method for importing WRF results into WAsP, ii. developing relationships between the sensitivity analysis and uncertainties, iii. continuing the measurements at current sites and additional sites, in order to improve and enhance the verification analysis.