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Investigation is conducted of the interannual variability of the northern Pacific storm track and its con current association with 500 hPa height and Pacific sea surface temperature (SST) during winter. Evidence suggests that during the studying period the center of the northern winter Pacific storm track experiences substantial interannual variability in the variation of its latitude, longitude and intensity. Singular value de composition (SVD) of 15 winter 500 hPa filtered geopotential height variance over the storm track with the tropical and northern Pacific SST shows that the first coupled mode depicts the effect on the track of SSTA over the equatorial central and eastern Pacific, while the second one reflects the impact of Kuroshio SSTA on the track. Further Composite analysis indicates, moreover, that the SSTA over Kuroshio (equatorial cen tral and eastern Pacific) during winter, which is relative to WP (PNA) teleconnection response pattern in 500 hPa height field, respectively, exerts crucial influence on the interannual variability in vigor and meridianal (zonal) displacement of the track over its central and western (eastern) part.

An influence of ENSO event on the maintenance of Pacific storm track in the Northern winter is studied based on the NCEP/ NCAR daily re-analysis data. The result shows that in El Nino (La Nina) year an increase (decrease) of baroclinicity over the storm track, extension (withdrawal) eastward and southward (westward but northward for its east end) of its position and augmentation (debilitation) of its strength are closely in response to the enhancement (abatement) of eddy heat flux and momentum flux that are associated with the development of the storm track. It thus indicates that ENSO event exerts an important impact on its maintenance and development in the Pacific Ocean.