In this study, the Fengyun-3D (FY-3D) clear-sky microwave temperature sounder-2 (MWTS-2) radiances were directly assimilated in the regional mesoscale Weather Research and Forecasting (WRF) model using the Gridpoint Statistical Interpolation (GSI) data assimilation system. The assimilation experiments were conducted to compare the track errors of typhoon Lekima from uses of the Advanced Microwave Sounding Unit-A (AMSU-A) radiances (EXP_AD) with those from FY-3D MWTS-2 upper-air sounding data at channels 5–7 (EXP_AMD). The clear-sky mean bias-corrected observation-minus-background (O-B) values of FY-3D MWTS-2 channels 5, 6, and 7 are 0.27, 0.10 and 0.57 K, respectively, which are smaller than those without bias corrections. Compared with the control experiment, which was the forecast of the WRF model without use of satellite data, the assimilation of satellite radiances can improve the forecast performance and reduce the mean track error by 8.7% (~18.4 km) and 30% (~58.6 km) beyond 36 h through the EXP_AD and EXP_AMD, respectively. The direction of simulated steering flow changed from southwest in the EXP_AD to southeast in the EXP_AMD, which can be pivotal to forecasting the landfall of typhoon Lekima (2019) three days in advance. Assimilation of MWTS-2 upper-troposphere channels 5–7 has great potential to improve the track forecasts for typhoon Lekima.

中文翻译：

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吸收FY-3D MWTS-2高空探测数据对预报台风勒基玛（2019）的影响

在这项研究中，使用网格点统计插值（GSI）在区域中尺度天气研究和预报（WRF）模型中直接吸收了风云3D（FY-3D）晴空微波温度探测器2（MWTS-2）辐射。数据同化系统。进行了同化实验，比较了使用高级微波探测单元-A（AMSU-A）辐射（EXP_AD）和FY-3D MWTS-2高空探测数据在台风5–时产生的台风莱基玛的跟踪误差。 7（EXP_AMD）。FY-3D MWTS-2通道5、6和7的晴空平均偏差校正后的观测负背景（OB）值分别为0.27、0.10和0.57 K，这比没有偏差校正的情况要小。与对照实验相比，该实验是在不使用卫星数据的情况下对WRF模型进行的预测，通过EXP_AD和EXP_AMD，对卫星辐射的同化可以改善36小时后的预测性能，并将平均航迹误差分别降低8.7％（〜18.4 km）和30％（〜58.6 km）。模拟转向流的方向从EXP_AD的西南方向更改为EXP_AMD的东南方向，这对于提前三天预测台风Lekima（2019）的登陆可能至关重要。MWTS-2对流层高空通道5-7的同化具有极大的潜力，可以改善对台风Lekima的航迹预报。这对于提前三天预测台风Lekima（2019）的登陆至关重要。MWTS-2对流层高空通道5-7的同化具有极大的潜力，可以改善对台风Lekima的航迹预报。这对于提前三天预测台风Lekima（2019）的登陆至关重要。MWTS-2对流层高空通道5-7的同化具有极大的潜力，可以改善对台风Lekima的航迹预报。