Predicting tropical cyclone (TCs) tracks is a primary concern in TC forecasting. Some TCs appear to move in a direction favorable for their development, beyond the influence of the steering flow. Thus, we hypothesize that TCs move toward regions with high water-vapor content in the lower atmosphere. In this study, four numerical experiments, including a control experiment and three sensitivity experiments, were performed using the Weather Research and Forecasting Model, to analyze the relationship between water vapor distribution and the track of Severe Typhoon Hato (2017). Observations validated the features reproduced in the control experiment. The sensitivity experiments were conducted to explore variations in the TC track under different water vapor environments. Results indicate that the horizontal distribution of water-vapor content exerted a greater impact on the TC track than the steering flow when both factors were significant. Further analysis revealed that the TC’s movement vector was between the direction of the steering flow and the direction toward the peak of vorticity increasing area. The peaks of vorticity increasing area were close to the peaks of water vapor increasing area, which also proved the effect of water vapor distribution on the TC track. These results are expected to improve TC track analysis and forecasting.

预测热带气旋 (TC) 轨迹是 TC 预测的主要问题。一些 TC 似乎朝着有利于其发展的方向移动，超出了转向流的影响。因此，我们假设 TC 向低层大气中水汽含量高的区域移动。本研究利用天气研究与预报模型进行了包括控制实验和灵敏度实验在内的四次数值实验，以分析水汽分布与强台风天鸽（2017）路径之间的关系。观察验证了控制实验中再现的特征。进行灵敏度实验是为了探索不同水汽环境下 TC 轨迹的​​变化。结果表明，当两个因素都显着时，水汽含量的水平分布对 TC 轨迹的​​影响大于转向流。进一步分析表明，TC的运动矢量介于转向流方向和涡度增加区域峰值方向之间。涡度增加区域的峰值与水汽增加区域的峰值接近，这也证明了水汽分布对TC轨迹的影响。这些结果有望改进 TC 轨迹分析和预测。涡度增加区域的峰值与水汽增加区域的峰值接近，这也证明了水汽分布对TC轨迹的影响。这些结果有望改进 TC 轨迹分析和预测。涡度增加区域的峰值与水汽增加区域的峰值接近，这也证明了水汽分布对TC轨迹的影响。这些结果有望改进 TC 轨迹分析和预测。