Effect of lateral boundary scheme on the simulation of tropical cyclone track in regional climate model RegCM3

摘要

The effect of the lateral boundary scheme in regional climate model (RCM) on the track simulation of tropical cyclone (TC) was investigated using RegCM3, for the case of Winnie (1997), which formed in the Western Pacific and landed on China in August 1997. The results show that there is an inevitable simulation error in the track of Winnie, and the narrower buffer zone size (BZS) will make a great error. However, it was demonstrated that a much broader BZS does not allow a better track simulation of Winnie, and the optimal BZS does not reduce the track error substantially. Moreover, the configuration scheme of nudging parameters plays an important role in the track simulation, and different nudging parameter configuration scheme could make the root mean square errors (RMSEs) of simulated track by more than two times. Nevertheless, the optimal configuration scheme can reduce the track error effectively by maintaining the equilibrium between the two additional nudging terms in the prognostic equations in the buffer zone, whereas both the strong nudging scheme and the weak nudging scheme distort the track simulation of the Winnie. It is also found that the simulated weaker west Pacific subtropical high (WPSH), which leads to the turning of the TC ahead of time, is the reason for the track simulation error. A possible approach for reducing track simulation error of TCs is also discussed.