Abstract: Based on the NCEP/NCAR reanalysis data from 1969 to 2013, the impacts of the northern polar vortex on the North Pacific storm track and its possible physical mechanism in recent 45 winters were analyzed.The results show that storm track is mainly located in the range of 120°E-120°W, 30°-60°N, and the strongest disturbance center is near 45°N.Singular Value Decomposition (SVD) suggests that there are two major coupled modes between the polar vortex and storm track.The first coupled mode depicts that the storm track is stronger (weaker) in the vicinity of its long-term mean locations while the polar vortex is stronger (weaker) in the polar region.The second mode depicts that as the polar vortex increases and shifts to the North Pacific, the storm track comparing to its mean state is stronger in the south of its long-term mean locations.On the contrary, as the polar vortex increases and moves to the north America, the storm track comparing to its mean state increases in the north of its long-term mean locations.A regression analysis further suggests that the anomalous change of polar vortex may give rise to change at 500 hPa geopotential height, and then change the East Asia westerly jet and the baroclinicity in the upstream of the storm track, and finally the storm track itself.

Key words: North Pacific storm track, Northern polar vortex, Teleconnection pattern