同化QuikSCAT资料对台风Vongfong(2002)数值模拟的影响

Assimilation of QuikScat Data and Its Impact on Prediction of Typhoon Vongfong(2002)

利用四维同化技术和中尺度数值模式MM5相结合对南海台风Vongfong(2002)的登陆过程进行了模拟,分析表明:同化Qu ikScat资料主要能使模拟的台风移动路径与实况更为接近。而台风的强度变化、降水量和降水分布的模拟与对流参数化方案有密切的关系,其中以Betts-M iller湿对流调整型方案最为合适。HFT试验模拟的台风路径、强度变化、暴雨分布和降水强度与实况一致。且试验结果较好地重现了Vongfong的一些异常特征,如路径突然折向北、移速先慢后快、近海强度加强、降雨量大、强暴雨中心落在台风西北侧等。利用非常规资料改善模式初始场,有逼真的物理过程,可以提高对台风登陆过程的预报。

As a mesoscale meteorological model, PSU/NCAR MM5 is utilized to make a series of multiscale numerical simulations of Typhoon Vongfong （2002） originated over the South China Sea （SCS）. As verified against various observations, Assimilation of QuikScat data into the model clearly shows an improvement in the simulation of Typhoon Vongfong. With assimilation of QuikScat data into the model, the typhoon track mainly can be simulation. moreover, Simulation of changes of the typhoon intensity and rainstorm distribution depend strongly on the cumulus parameterization. From the simulated results, it might be shown that Betts-Miller scheme appears to be more suitable for the simulation of landfalling process of Typhoon. Compared with the general typhoons in the SCS, Vongfong has anomalous features as enhancing inshore, slow-moving turned to fast -moving, turned suddenly to move northward, with a largd amount of rainfall centralized in the northwest of the typhoon center. The model reproduced these anomalous features, such as the track, moving pace, intensity changes, rainfall and precipitation distribution. The results suggest that it may be possible to predict reasonably the track, intensity, precipitation and inner-core structure of Typhoon if with good initial conditions, realistic model physics and high grid resolution are incorporated.