Variation in the Vertical Structure of the Winter North Pacific Storm Track and Its Relationship with Extreme Low Temperature Activity in China

The spatiotemporal evolution of the North Pacific storm track in winter was studied on the basis of NCEP-NCAR reanalysis data and ERA-40 reanalysis data.The results showed an evident interannual variation in the North Pacific storm track, and two main vertical structure modes were clarified.The first mode is consistent over the entire region, and the second is a vertically opposite mode.Thus, four vertically anomalous types of storm track are apparent:those with a consistently strong pattern, those with a consistently weak pattern, those with an upper-level strong and lower-level weak pattern, and those with an upper-level weak and lower-level strong pattern.It was also found that the vertical structures of the storm tracks are closely related to extreme low temperature in China.Specifically, the consistently strong pattern(consistently weak pattern) correlates closely with relatively weaker(relatively stronger) extreme low temperature over the whole of China.Meanwhile, the upper-level strong and lower-level weak pattern(upper-level weak and lower-level strong pattern) correlates closely with relatively stronger(relatively weaker) extreme low temperature in Northeast China and relatively weaker(relatively stronger) extreme low temperature in other regions.