Association of the Zonal Migration of North Pacific Storm Track With the East Asian Monsoon in Boreal Wintertime

The winter North Pacific storm track (WNPST) distinctly manipulates weather and climate in the midlatitudes. Thus, it is necessary to comprehend the factors and related mechanisms governing the location and intensity of WNPST. In the present study, the influence of the East Asian winter monsoon (EAWM) on the zonal movement of the WNPST represented by the lower-tropospheric meridional eddy heat flux is investigated, and the possible physical processes are analyzed. There is a significantly positive correlation, especially interannual signal, between the strength of the EAWM and the zonal position of the WNPST. The Liang-Kleeman information flow theory is used to prove the mutual causality between the intensity of EAWM and the zonal migration of WNPST. The EAWM-related intensity anomaly pattern of the WNPST, with prominently negative anomalies over the northwest Pacific and significantly positive anomalies over the northeast Pacific, is associated with the eastward movement of the WNPST. In addition, the results show that the patterns of anomalous lower-tropospheric atmospheric baroclinicity and barotropic energy transfer do not match the EAWM-related anomalous WNPST. The upper-tropospheric jet anomalies may be related to the weakening in the peak area and the western flank of the climatological WNPST. The impact of the EAWM on the zonal movement of the WNPST can be related to the anomalous baroclinic energy transfer and buoyancy conversion. Furthermore, the moisture effect including anomalous meridional and vertical eddy moisture flux may also play a role by latent heat release.

Automated summary

The study found that the East Asian winter monsoon significantly influences the zonal movement of the winter North Pacific storm track, with a significantly positive correlation between the two. This could be due to anomalous climate factors and mismatched distribution patterns between the two.