Based on the methods of multivariate EOF(MVE-OF) and lead-lag correlation and regression analysis,the spatiotemporal variations of the 10 m horizontal wind over the tropical Pacific(10°S-10°N,100°E-60°W) and their associations with East Asian atmospheric circulation were investigated using the monthly global NCEP/NCAR reanalysis data for the period 1958 to 2001. The MV-EOF results show that there are two leading modes of the 10 m horizontal wind anomalies over the tropical Pacific.The first leading mode captures the well-known wind anomaly pattern associated with El Niño(La Niña),and is also characterized by the equatorially quasi-symmetric westerly(easterly) wind anomalies over the central Pacific and convergence(divergence) onto the equator in the east.The corresponding PC time series(PC1) is highly correlated(R=0.74) with the time series of the Niño3.4 index,suggesting that PC1 captures the main ENSO mode and that the mode corresponds to the low-level horizontal wind anomalies during the warm(cold) phase of ENSO.The second leading mode,however,is highly antisymmetric about the equator and exhibits a pattern of easterly(westerly) anomalies north of the equator and westerly(easterly) anomalies south of the equator,along with a strong low-level anticyclonic(cyclonic) circulation anomaly over the western North Pacific.The westerly(easterly) anomalies south of the equator,at about 10°S,in the central Pacific,correspond to the southward displacement of zonal wind anomalies during the decaying spring season of El Niño(La Niña),which is in accordance with the wind anomalies during the transition phase of ENSO.The corresponding PC2 usually emerges rapidly several months after the PC1 peak.The two corresponding time series both feature significant interannual varibility and seasonal phase-locking characteristics,but their dominant oscillation periods and relationships with the ENSO cycle vary prominently. The lead-lag regression analysis reveals that persistent significant anomalous positive(negative) geopotential height at 500 hPa and remarkable anticyclonic(cyclonic) atmospheric circulations at 850 hPa are set up to the south of Lake Baikal(SLB) when the two leading modes are in their positive(negative) phases.Further examination of the corresponding velocity potential quantities show that the connection pathways between the two modes and the anomalous SLB circulations differ from one another.The first mode,which is characterized by abnormal dipole Walker Circulation forced by the warm water in the eastern tropical Pacific,may be affected by the anomalous SLB circulation through the northerly winds over the East Asian coast and the South China Sea trough during its developing period.In addition,the anomalous SLB circulation also plays an important role in the maintenance of the mode after it matures.The circulation is linked with large-scale vertical motion over the central eastern tropical Pacific,and also the abnormal convergence motion over Southeast China.The opposite situation occurs when the first mode is in its negative phase.The second mode features abnormal quadrupole Walker Circulation forced by the warm water over the regions from the eastern tropical Indian Ocean to the western tropical Pacific,as well as the Atlantic Ocean.Thus the corresponding anomalous SLB circulation may be mainly related to the strong meridional Hadley Circulation over the the region from the eastern tropical Indian Ocean to the western tropical Pacific,and vice versa.