Daily and weekly sea surface temperature data of Tropical Rainfall Measuring Mission (TRMM) Microwave Imager and Advanced Microwave Scanning Radiometer-Earth Observing System sensors are used as forcing of the underlying sea surface in the mesoscale numerical model to simulate Typhoon Dujuan that moved across the South China Sea in 2003. The numerical results show that different SSTs near the typhoon center result in differences in the atmospheric wind field, indicating that the model has a fast and obvious response to SSTs. Different SST influences the intensity and track of Dujuan to some degree and has significant impacts on its precipitation and latent heat flux near the eye. The SST influence on Dujuan is mainly fulfilled by changing the latent heat flux between the ocean surface and the atmosphere above.
基于GRAPES(Global/Regional Assimilation and Predition System)三维变分同化系统,设计在6小时内分别应用三小时一次和逐小时的台风定位和定强信息对台风进行多次BDA(Bogus Data Assimilation)同化,在多次BDA中只同化近似程度高的涡旋风分量而近似程度较差的辐散风分量则通过多次调整和协调逐步向涡旋风适应。多次BDA能逐步调整台风位置并且在同化过程中随着台风位置更接近实况,使得台风周围流场更趋合理。采用多次BDA方案对"天鹅"(0907)台风进行数值试验,结果表明多次同化方案能逐步改进台风中心附近的环流场信息,与一次BDA相比,得到的初始场结构更协调,对台风的路径和降水预报也有一定改善。
