2020年西北太平洋台风活动特征和预报难点分析

The Analysis of Characteristics and Forecast Difficulties of TCs in Western North Pacific in 2020

利用1949—2019年中国气象局台风最佳路径资料、2020年中央气象台的台风路径和强度实时预报资料、欧洲中期预报中心的ERA-Interim逐6 h再分析资料(水平分辨率为0.25°×0.25°),以及NCEP RTG_SST海温分析产品等,对2020年西北太平洋台风活动的主要特征和预报难点进行了分析。结果表明:2020年度,台风生成和登陆个数偏少、强度偏弱;台风生成源地偏西;台风活动的阶段性、群发性特征突出和近海快速加强特征明显。对2020年度的预报误差进行分析,结果显示:24、48、72、96、120 h台风路径预报误差分别为70、117、169、222、276 km,各时效误差均较2019年有所减少;24、48、72、96、120 h台风强度预报误差分别为3.9、5.1、5.5、6.2和6.3 m·s^(-1),较2019年也明显减小,24 h误差连续4年小于4.0 m·s^(-1)。另外,2020年度最主要的台风预报难点在于,一是近海快速加强台风的强度预报,二是北上台风登陆后的陆上强度维持。

The characteristics of TCs on Western North Pacific in 2020 are analyzed by using the best-track data,CMA operational forecasting data,ECMWF ERA-Interim reanalysis products and NCEP RTG_SST data.Results show that the number of typhoons and landing typhoons were less and the strength were weak in 2020.The generating locations were inclined more westward.The stage and group characteristics of typhoon activity were prominent,and the features of offshore rapid intensification(RI)were obvious.Estimations of track errors in 2020 show that there were some decreases compared to those of 2019,with the error values of 70,117,169,222 and 276 km for the forecasts with 24,48,72,96 and 120 h lead time,respectively.The strength errors were 3.9,5.1,5.5,6.2 and 6.3 m·s^(-1) for the forecasts with 24,48,72,96 and 120 h lead time,respectively and decreased a little compared to the errors of 2019.The 24 h errors were less than 4.0 m·s^(-1) for 4 consecutive years.In addition,the forecast difficulties in 2020 lie in that,first,the strength forecast of RI TCs off-shore,and second,the strength forecast of typhoons going northward after landing.