The North Pacific Ocean has a complex circulation system and is thus sensitive to global atmospheric and oceanic changes. Mesoscale eddies are widely found in this region. Research on the distribution characteristics and motion features of mesoscale eddies is very important in explaining the energy change and air-sea interaction in the region. In this study,the merged altimeter data obtained from AVISO are used to identify and trace the mesoscale eddies in the North Pacific（ 100° E—77° W,0° N—70° N）from 1993 to 2012. The attribute characteristics（ such as amplitude,radius,and speed）,spatial distribution,and transmission characteristics are statistically analyzed. The seasonal,interannual,and decadal variabilities are also studied. The SLA-basedmethod is used to identify mesoscale eddies based on the outermost closed contour of sea level anomalies. This algorithm is widely used because of its high accuracy. The tracking method applied is a combination of the nearest distance method and the similaritybased method. If no trace is observed for two weeks,the eddy is considered to have disappeared. The tracking process needs to last at least four weeks. The average amplitude and speed of the eddies in the North Pacific are 8. 44 cm and 6. 4 cm / s,respectively.An eddy can continue for about 6. 9 wk. Unlike those of cyclones,the amplitude and lifetime of anticyclones obviously change in different zonal bands. As latitude increases,the propagation speed of eddies gradually reduces. Eddies are abundant in California,the Gulf of Alaska,and especially in the Kuroshio Extension. Most of these eddies propagate west nonlinearly. Anticyclones are prone to poleward deflections,whereas cyclones are prone to equatorward deflections. Eddies occur frequently in spring and summer and occasionally in autumn and winter. Seasonal variations are apparent in California. The interannual variabilities of the number of eddies are closely related with the ENSO phenomena. In 1993 to 2002,the number of eddies was positively relative to the EMI index,but in 2003 to 2012,it was negatively relevant. We focused on the spatio-temporal distribution characteristics of mesoscale eddies in the North Pacific and analyzed the distribution differences from 1993 to 2002 and from 2003 to 2012. The differences were mainly observed in the subtropical countercurrent area and in the open ocean in the Northeast Pacific. However,the mechanisms of eddy genesis and the causes of the differences in temporal and spatial distribution must be analyzed with a physical ocean model. This aspect should be implemented in future research.

satellite altimeter;mesoscale eddy;North Pacific;temporal and spatial characteristics;ENSO