Typhoon Sanba (2012), the strongest tropical cyclone (TC) of the year worldwide, moved northward almost along 130° longitude during its lifetime and passed through different background flows from low to high latitudes. The steering flows with different timescales for Sanba are retrieved by using the NCEP reanalysis data with the total wind field separated into: a mean state, an interannual component, an intraseasonal component, and a synoptic component. Our analysis indicates that the intraseasonal timescale wave train (WT) with east-west oriented circulations made the largest contribution to the movement of Sanba. The effects of the environmental steering with different timescales on Sanba’s movement are investigated with numerical simulations using the Weather Research and Forecasting (WRF) model. In the control simulation, total fields from the NCEP reanalysis are used as initial and boundary conditions, and the northward motion of Sanba is well captured. In sensitivity experiments, each of the intraseasonal and interannual components is removed one at a time. The steering vectors associated with these timescales can explain their influences on the movement of Sanba in the experiments. Vorticity budget analyses indicate that the horizontal vorticity advection made the largest contribution to the movement of the storm.

Sanba台风（2012）是全球年度最强的热带气旋（TC），在其一生中几乎沿经度130°向北移动，并经历了从低纬度到高纬度的不同背景流。通过使用NCEP再分析数据将Sanba的不同时标的转向流进行检索，总风场分为：平均状态，年际分量，季节内分量和天气分量。我们的分析表明，具有东西向环流的季节内时标波列（WT）对Sanba的运动贡献最大。使用天气研究和预报（WRF）模型，通过数值模拟研究了不同时间尺度的环境转向对Sanba运动的影响。在控制仿真中 来自NCEP重新分析的全部场都用作初始条件和边界条件，并且很好地捕捉到了桑巴的向北运动。在敏感性实验中，每个季节内和年度间的组件一次都被删除。与这些时标相关的操纵向量可以解释它们对实验中Sanba运动的影响。涡度预算分析表明，水平涡度对流对风暴运动的影响最大。