Abstract
In Tsugaru Strait and its mixed water region, concentrations of Ra-226, Ra-228 were measured and compared with distribution of the water masses. Ra-226, Ra-228 concentrations were different from Tsugaru warm current to Oyashio current, and it was possible to distinguish both waters clearly by radium isotopes. In addition, the relation with the path of Tsugaru warm current was discussed the seasonal variation of Ra-226, Ra-228 conncentrations in seawater sample collected from Rokkasho and Oma coast.
