基于Resnet50的江苏近海海面风场预报订正方法研究

Correction method for surface wind forecasts in Jiangsu offshore area based on Resnet50

海面风场的精确预报对于海上风能开发具有非常重要的影响。利用2019—2021年ERA5再分析数据系统评估了欧洲中期天气预报中心的EC细网格10 m风场预报在江苏近海区域的预报准确性,发现EC细网格对于该区域4级风的预报准确性最高,24 h(48 h)风速预报的均方根误差为2.28 m/s(2.34 m/s),但是随着风级增大,风速预报的准确性大幅降低,5~11级风24 h(48 h)预报的均方根误差(RMSE)由2.39 m/s(2.58 m/s)增加到8.67 m/s(8.51 m/s)。此外,风速预报误差存在显著的空间差异性,误差随着离岸距离的增大而增大。在此基础上,基于Resnet50模型构建了江苏近海海面风场预报订正模型,并利用2022年的预报数据对其进行独立性检验。结果表明:订正模型可以显著改善EC细网格24 h(48 h)的10 m风速预报结果,订正后的RMSE为1.45 m/s(1.66 m/s),较订正前降低了45%(40%)。对于3~10级风,订正模型24 h和48 h预报的RMSE为1.13~6.67 m/s和1.21~5.68 m/s,同样明显低于订正前(2.33~7.65 m/s和2.58~9.97 m/s)。

Accurate forecasts of surface winds plays an important role in offshore wind energy development.This study uses the ERA5 reanalysis data during 2019‒2021 to evaluate the EC fine-grid 10 m winds forecasts in Jiangsu offshore area.It is found that the EC fine-grid 10 m wind speed forecasts perform best in accuracy for wind scale 4,with a 24 hour(48 hour)forecasting RMSE of 2.28 m/s(2.34 m/s).As wind scale increases,the wind speed forecasting accuracy decreases significantly,and the 24 hour(48 hour)forecasting RMSE for wind scales 5~11 increases from 2.39 m/s(2.58 m/s)to 8.67 m/s(8.51 m/s).In addition,significant spatial differentiation exists in the 10 m wind speed forecast errors,and the errors grow along with the increase of offshore distance.Based on the Resnet50 model,a correction method for surface wind forecasts in Jiangsu offshore area is constructed.The independence test using the forecasting data in 2022 shows that the correction method significantly improves the accuracy of the EC 24-hour and 48-hour 10 m wind speed forecasts,with a 24 hour(48 hour)forecasting RMSE of 1.48 m/s(1.65 m/s),which is 45%(40%)lower than the original EC forecasts.For wind scales 3~10,the 24-hour and 48-hour corrected forecasting RMSE are 1.13 m/s to 6.67 m/s and 1.21 m/s to 5.68 m/s,which is also significantly lower than the original EC forecasts(2.33 m/s to 7.65 m/s and 2.58 m/s to 9.97 m/s).