In this study, the dynamics of track deflection associated with Tropical Cyclone (TC) Sidr (2007) are explored using a numerical weather prediction model. It is found that (a) the simulated track of Sidr is sensitive to flow, orographic, and model vertical structure that change the environmental steering flow leading to the track deflection. In particular, the track of TC Sidr is deflected northwestward for cases with lower domain height, horizontal domain covering only part of Himalaya mountains, and varying mountain heights; (b) the simulated track of TC Sidr, when compared with GFS reanalysis data, is mainly controlled by its deep-layer environmental steering flow as a point vortex; (c) the northwestward deflection with lower domain height is caused by an artificially larger high pressure at lower levels in the vicinity of the Himalayas, due to the upward propagation of wave energy being reflected by the upper domain boundary; (d) the significant northwestward deflection associated with the varying mountain height cases is due to the cyclone vortex being advected by the northeasterly monsoonal flow, which is blocked by the mountains in the corresponding cases with mountains; (e) the northeastward track deflection after the landfall of Sidr is explained by the addition of the frictional force.

In summary, the model vertical domain height and the Himalaya mountain representation play key roles in influencing the accuracy of TC Sidr track simulation, compared with other factors, such as the vertical resolution, at least for TC Sidr.

在这项研究中，使用数值天气预报模型探索了与热带气旋（TC）Sidr（2007）相关的磁道偏转动力学。发现（a）Sidr的模拟轨迹对流量，地形和模型垂直结构敏感，这些结构会改变导致转向的环境转向流。特别是，对于低磁畴高度，水平磁畴仅覆盖喜马拉雅山脉的一部分以及山高不同的情况，TC Sidr的轨迹向西北偏转。（b）与GFS再分析数据相比，TC Sidr的模拟轨迹主要受其深层环境转向流作为点涡的控制；（c）具有较低域高度的西北偏斜是由喜马拉雅山附近较低水平的人为较大的高压造成的，由于波能量的向上传播被上限域边界反射；（d）与变化的山高情况有关的西北偏大，是由于旋风涡旋被东北季风气流平流所致，在相应的山脉情况下，该气流被山脉阻塞了；（e）Sidr登陆后的东北轨道偏转是通过增加摩擦力来解释的。

总之，与其他因素（例如垂直分辨率）相比，至少对于TC Sidr，模型的垂直域高度和喜马拉雅山脉表示法在影响TC Sidr轨迹模拟的准确性方面起着关键作用。