沙岭风场风速预报试验分析

An Experimental Analysis of Wind Speed Prediction in Shaling Wind Field

本文应用MM5模型对鄱阳湖区风速进行数值模拟,应用沙岭风场100m梯度测风铁塔数据进行相关分析和验证,发现观测与模拟小时和日均风速值的变化趋势较为一致,在峰值区一般MM5预测值比观测值小,相对观测值而言,模式模拟值变化相对平缓。MM5模型风速模拟值与观测值的小时和日均偏差分别为0.323和0.371,标准差分别为2.382和1.453。模拟风速日均值与观测日均值的相关系数为0.774。尽管不完善,数值模拟在目前的风能短期预报业务中仍起重要作用,也是未来风速预报和风力发电量预报的发展方向。

It is critical to forecast wind energy resources for a specific wind field to provide meaningful information and reference to exploit them for decision-making.In the present study,the authors simulated wind fields across the Poyang Lake areas during the period 2007-2008 and analyzed in detail the simulations from the Fifth-Generation NCAR/Penn State Mesoscale Model （MM5）by comparing them with observations at a wind tower in Shaling wind field.The wind tower in Shaling wind field was installed with the Huayun wind systems,measuring wind direction,wind speed,temperature,humidity,air pressure and rainfall.It was found that simulations of hourly and daily wind speed were in well agreement with observations.In general, extreme predictions from the MM5 model were smaller compared with the observations.On the whole,the predictions from the MM5 were highly correlated with observations.Nevertheless,there still existed certain differences between the simulated and the observed values,showing mean deviations of 0.323 and 0.371,and standard deviations of 2.382 and 1.453 on an hourly and daily basis,respectively.The daily correlation coefficient between simulated and observed values was found to be 0.774.From the perspective of temporal scale of simulations,it was indicated that the longer the period of simulation,the better results would be obtained.The absolute differences between simulated mean monthly hourly wind speed and observations were roughly 1 m/s;the absolute differences between simulated mean daily wind speed and observations lay between 0 m/s and 3 m/s;the absolute differences between simulated hourly wind speed and observed ones basically concentrated on the range of 0 m/s to 4 m/s.As for wind speed distribution,it was shown that there was certain discrepancy between the observed and simulated values.Observed values appeared more frequently than did the predictions from the MM5 under the condition that the wind speed was greater than 7 m/s.However,the MM5 predictions appeared more frequently than did the observations under the condition that the wind speed was between 4m/s to 7 m/s.It was demonstrated in the study that numerical simulation still play an important role in short-term forecasting of wind energy despite some uncertainties under certain circumstances and it is also an effective way for wind forecasting and wind energy predictions in the future.