[en] Three vertical water profiles of ²¹⁰Pb and ²¹⁰Po have been measured in the East China and Philippine seas. All the profiles show a large ²¹⁰Po deficiency of ∼ 8 dpm/cm² relative to ²¹⁰Pb in the top ∼ 1,000 m of the water column. Based on the ²¹⁰Po deficiency, the steady state flux for ²¹⁰Po removal from the surface water is estimated to be 14 dpm cm^-2/yr. The ²¹⁰Po/²¹⁰Pb ratio of sinking particles will be too high unless an additional source of ²¹⁰Pb into the surface is accounted for. Thus the large ²¹⁰Po deficit is probably caused by the increased atmospheric input of ²¹⁰Pb without any significant ²¹⁰Po, which is focused in the Kuroshio region by isopycnal transport, and the preferential scavenging of ²¹⁰Po relative to ²¹⁰Pb by settling particles. The transient model calculations indicate that the model can account for the observed high excess ²¹⁰Pb inventory and large ²¹⁰Po deficiency in the water column if focusing of atmospherically derived ²¹⁰Pb in the Kuroshio water is a factor of 2-3 more than the local input. Such lateral redistribution by the western North Pacific gyre circulation is not inconsistent with the deeper penetration and the high water column inventories of anthropogenic substances observed in this region