Modulation of winter precipitation associated with tropical cyclone of the western North Pacific by the stratospheric Quasi-Biennial oscillation

Tropical cyclone precipitation (TCP) has increasing impacts on many coastal regions under global warming. Causes of TCP variation have been principally explored in the troposphere. This study identifies the significant modulation of the stratosphere Quasi-Biennial oscillation (QBO) on the winter TCP in the coastal regions of the western North Pacific (WNP). In the westerly QBO winter, the zonal wind vertical shear anomalies in the stratosphere strengthen (weaken) convective activities around the East China Sea (the Philippines) and cause middle-level easterly (westerly) anomalies of the middle (low) latitudes in the troposphere, leading to more (less) TC activities around the East China Sea (the Philippines). Consequently, a TCP dipole pattern can be observed. The TCP increases in East China, Korean peninsula, Japan and Russian Far East, but decreases in Indo-China Peninsula, South China and the Philippines. These results not only improve the knowledge of QBO-TCP relationship but also provide a potential indicator for the seasonal prediction of the TCP in the coastal regions of the WNP due to the high predictability of the QBO.

Automated summary

This study identifies the significant modulation of the stratosphere Quasi-Biennial Oscillation (QBO) on the winter Tropical Cyclone Precipitation (TCP) in the coastal regions of the western North Pacific (WNP). The research found that in the westerly QBO winter, there are anomalies in zonal wind vertical shear in the stratosphere which affect convective activities and lead to changes in TC activities in specific areas, resulting in a dipole pattern of TCP. As a result, TCP increases in some areas such as East China, Korean peninsula, Japan, and Russian Far East, while it decreases in others like Indo-China Peninsula, South China, and the Philippines. This provides a potential indicator for seasonal prediction of TCP in these regions.