The observation of wind over oceans remains challenging. This results in difficulty in predicting the wind speed and direction. In this study, we examined the accuracy of upper-tropospheric wind speed forecasts along the flights between Tokyo International Airport and Los Angeles International Airport. We compared the Global Spectral Model data from the Japan Meteorological Agency (as forecast data) with the observation data from the aircraft's Quick Access Recorder (as true values). The forecast errors are highest over the North Pacific Ocean, not at the end of flight when the elapsed hours are longest, with meridional winds having a larger forecast error than zonal winds. Analysis of the meteorological field where a large meridional wind forecast error occurred using ERA5 indicates that the convergence-divergence of the jet stream or the blocking of westerly winds by the upper trough may have affected the large forecast error.

海洋风的观测仍然具有挑战性。这导致风速和风向的预测变得困难。在这项研究中，我们检查了东京国际机场和洛杉矶国际机场之间航班上对流层风速预报的准确性。我们将日本气象厅的全球光谱模型数据（作为预报数据）与飞机快速访问记录器的观测数据（作为真实值）进行了比较。北太平洋上空的预报误差最高，而不是在飞行结束时经过的时间最长，经向风的预报误差比纬向风更大。利用ERA5对经向风预报出现较大误差的气象场进行分析表明，急流的辐合发散或高槽对西风的阻挡可能是造成预报误差较大的原因。