Abstract:Base on the reanalysis data of NCEP/NCAR and NOAA, index of Nino3.4 from CPC,influences of different ENSO phases corresponding to SST(sea surface temperature) anomalies in the equatorial middle-eastern Pacific on the coupled pattern of atmosphere-ocean system and the concurrent variations of northern Atlantic and Pacific storm tracks are investigated. The results are summarized as follows:1) The equatorial middle-eastern Pacific SST anomalies are closely related to the concurrent variations between the two storm tracks in boreal winter. When SST anomaly is in positive phase,the two storm tracks are intensified with the whole Atlantic storm track and eastern part of Pacific storm track shift southward. Meanwhile, concurrent variations of the two storm tracks are opposite as SST anomaly is in negative phase.2) When SST anomaly is in positive phase (El Nio), in the middle troposphere, the polar vortex extends toward the northern Pacific, the north-west pacific subtropical high is intensified and moves westward, the East Asian trough is weakened, and the geopotential height anomalies is characterized by the negative phase of WP and EA teleconnection and positive phase of PNA teleconnection. In the low-troposphere, the Canada high is intensified, the Aleutian low is intensified and shifts southeastward, the Jet in East Asia is intensified and extends eastward, the Jet in North America is intensified, and the westerly near 50°N over Eurasia is intensified with weakened meridional circulation. The baroclinic energy anomalies in the Northern Hemisphere enhance the conversion from available potential energy to eddy kinetic energy, resulting in intensified Pacific storm track and the southward shift of eastern storm track. The increase of baroclinic energy to the south of the Atlantic storm track results in southward shift of the whole Atlantic storm track and an intensification in its middle-western parts. When SST anomaly is in negative phase (La Nia), anomalies of SST and circulation are opposite to variations of storm tracks in positive phase.3) When SST anomaly is in positive phase (El Nio), it was warmer in the north and colder in the south over the North American continent in the low-tropospheric temperature field. Temperature anomalously increase over East Asia in area south of 60°N except southwest China. When SST anomaly is in its negative phase (La Nia), the abnormal temperature increase is mainly in the south of North America and north of East Asia, because anomalies of geopotential height and wind in Eurasia and North America are not exactly the opposite to those in El Nio phase.