Possible Influence And Mechanism Of The North Pacific Storm Track On China Air Temperature During Winter

Based on the daily minimum temperature data provided by the National Climate Center of the China Meteorological Administration and National Center for Environmental Prediction/National Center for Atmospheric Research(NCEP/NCAR)reanalysis data from1961 to 2017,this paper have analysed the main variation characteristics of North Pacific storm track and winter temperature in China,and the possible influence of North Pacific storm track on winter temperature in China on the interannual scale,and diagnoses the effect of storm track anomaly on the winter temperature in China.The main conclusions are as follows:(1)By using correlation analysis and SVD analysis,the relationship between storm track and winter temperature in China is found that the intensity change of storm track is most closely related to the winter temperature in China.When the storm track weakens(strengthens),the winter temperature in China is generally lower(higher).Further regression analyses show that the intensity change of North Pacific storm track in winter is closely related to the atmospheric circulation in East Asia.When the storm track weakens,the 500 h Pa geopotential height field shows the positive phase of EU and WP teleconnection,and the meridional circulation in the mid-high latitudes;on the 300 h Pa zonal wind field,the polar front jet is weakened,and the subtropical jet is strengthened;on the sea level pressure field,the Siberian high is strengthened and the Aleutian low is deepened,which makes the winter monsoon stronger.A cold mass is formed in south of Lake Baikal,resulting in low temperature weather in China.(2))It is of great significance for the formation and maintenance of the atmospheric circulation that the momentum and heat transfer of synoptic transient eddies in the North Pacific.When the storm track weakens,the momentum transport of transient eddies leads to the deepening and southward movement of the East Asian Trough,and is conducive to the maintenance of positive phase of WP teleconnection,the strengthening of the subtropical jet,the deceleration of the westerly flow on the north side,the strengthening of Siberia High and the deepening of the Aleutian Low.The anomalous center of the atmospheric circulation caused by the transient eddies is basically the same as that of the actual atmospheric circulation anomalies.These atmospheric circulation anomalies are conducive to the strengthening of winter monsoon,which leads to a wide range of low temperature weather in China.However,the temperature anomaly of the time average flow caused by the transient heat transfer is not obvious in China.