Abstract:In order to find the effect of the upper-level jet on tropical cyclones (TCs), ten landing tropical cyclones from the Yellow Sea or the Bohai Sea are divided into the northern-moving pattern and northeastern-moving pattern, and a set of composite analyses based on the data of ECMWF are conducted. The result shows that the TCs actually tend to move in the right side of the upper-level jets, and tend to be approaching up to the entrance of the maximum wind speed zones of the jets. In addition, when TCs approached to the jets, the lower-level motions around the TCs appeared a second-order maximum speed center of horizontal wind components and a centrifugal growth of convection in consequence. The upward motion caused by the divergence linked to the upper-level jet is regarded as the main reason of the changes of the horizontal and vertical motions of the TCs.