2012—2021年中央气象台台风3~5 d路径预报误差分析

Analysis of typhoon track forecast errors for 3~5 days by Central Meteorological Observatory from 2012 to 2021

2012—2021年中央气象台台风3~5 d路径预报误差统计结果表明,虽然大误差的样本数仅为小误差样本数的1/12,但其贡献的误差占到后者的1/2,在预报误差整体降低的趋势背景下,大误差随时间变化无显著下降趋势。对大误差的分布特征及来源进行分析,其来源于4种台风类型:转向变性型(ET,60.6%)、双台风型(BT,24.2%)、弱引导气流型(WB,9.1%)和异常型(NSF,6.1%)。进一步总结天气形势场,可以得出:ET型会因低估台风变性后的移速导致大误差;BT型由于双台风作用导致的打转和异常转折等复杂路径,导致预报难度高;WB型台风引导气流弱且方向多变,导致移向误差大;NSF型会因预报移向失误导致大误差。

The statistical results of typhoon track forecast errors for 3~5 days issued by Central Meteorological Observatory from 2012 to 2021 show that although the number of samples with large errors is only 1/12 of that with small errors,the errors it contributes account for 1/2 of the latter.Although the overall forecast error decreases,there is no significant decreasing trend in large errors over time.The analysis of the distribution characteristics and sources of large errors reveals that they come from four types of typhoons:extratropical transition type(ET,60.6%),binary typhoons type(BT,24.2%),weak background type(WB,9.1%)and nonsteering flow type(NSF,6.1%).By further summarizing the synoptic situation field,it is pointed out that the large errors of ET type is caused by the underestimation of the typhoon’s moving speed after its transition;the complex tracks such as rotation and abnormal turning caused by the effect of binary typhoons make it very difficult to forecast for the BT type;the WB type has weak and direction-variable guiding flow,resulting in large error in direction;the large errors of NSF type is caused by the error in direction forecasting.