The Application of NCEP/NCAR Reanalysis Data to the Assessment of the Wind Resource
NCEP/NCAR再分析数据在风能资源评估中的应用研究

Measure-Correlate-Predict (MCP) is not only a primary technical method to evaluate the development level of wind resource of a wind farm in plan, but it can also determine the annual energy production. The result of MCP can be influenced by the long term wind reference data, which means that if the long term wind reference data is low in credibility, the result of MCP is also unreliable; and then the wind resource assessment of the wind farm in plan can be false. However, in engineering practice, the long term wind reference data from meteorological stations can be affected by some objective factors, such as the new buildings around the wind masts; small trees around the wind masts can grow up to 20m or even higher, which would also affect the wind data. The NCEP/NCAR reanalysis dataset, which are produced by National Centers for Environmental Prediction (NCEP) and National Center for Atmospheric Research (NCAR), is widely used as an alternative long term wind reference data. The dataset is available from January 1 in 1948 to the present and data samples are recorded every 6 hours. Surface wind data and 10 m wind data are available and are saved on a grid at 2.5 degree resolution at different air pressure levels ranging from 10 hPa to 1000 hPa. This paper studies the application of the NCEP/NCAR reanalysis dataset in the wind resource assessment, because of the low resolution of the NCEP/NCAR reanalysis dataset and the general MCP methods, such as the regression method, the Weibull scale method and the matrix method, are not sufficient any more; therefore, a new MCP method, named as wind index, is presented. For evaluate the feasibility of the dataset and the new MCP method, a case study is carried out. The calculated energy production of the studied wind farm, which is based on the long term wind reference data from meteorological stations and NCEP/NCAR reanalysis dataset are compared. The result shows that the calculated energy production is very close to real energy production, which means that different long term reference wind data and different MCP methods show almost same development level of wind resource. Therefore, it can be concluded that the combination of the NCEP/NCAR reanalysis dataset with wind index MCP method is a very reliable MCP calculation principle and can have a good practical value.