台风网格风场主客观融合技术的应用及评估

APPLICATION AND VERIFICATION OF TYPHOON GRIDDED WIND-FIELD SUBJECTIVE AND OBJECTIVE FORECAST FUSION TECHNIQUE

针对实际预报工作中,台风主观预报和模式风场客观预报不一致的问题,基于南海台风模式(CMATRAMS)资料、实时台风主观预报资料,采用一种考虑下垫面作用的动力解释应用方法TCwind,得到了能较合理描述台风风场的数学方程组,结合网格预报技术,进行台风主观预报和模式风场的主客观融合,实现了台风风场预报的订正,能为网格预报提供有效辅助。以实时台风主观预报为评判标准,检验评估了2018—2019年西北太平洋所有台风的融合订正效果,发现订正后的台风风场中心能较准确地向主观路径预报调整;台风中心附近最大风速相较模式显著增强,趋近主观强度预报;台风环流风速比模式原始风速增大,风场结构分布相比模式原始风场也更合理。

In the present study,the fusion technique of typhoon subjective and objective forecast is introduced by using the TRAMS-18km numerical model and real-time typhoon subjective forecasting data,and utilizing the gridded forecast technique and a dynamical interpretation method considering the effect of underlying surface to derive the equations of typhoon wind-field,which would calibrate the typhoon windfield forecast and help to improve the fineness of gridded forecast.The data after the fusion of subjective and objective forecast of typhoons over the Northwestern Pacific from 2018 to 2019 are compared with real-time typhoon subjective forecasting data.The result show that:(1)The cyclonic center of calibrated wind-field circulation coincides or is close to the typhoon center in subjective forecast.(2)The maximum wind speed of calibrated wind-field center exceeds the maximum wind speed predicted by the numerical model,and matches the maximum wind speed of typhoon center in subjective forecast in most cases.(3)The wind speed of typhoon circulation is higher than that predicted by the numerical model,and the structure of calibrated wind-field conforms to physical laws and is more reasonable than that predicted by the numerical model.