| Seawater samples collected in the northeast Pacific from 112 degrees 50'W to 126 degrees 36'W along a latitudinal band (21-25 degrees N) have been analysed for Ra-228 and Ra-226. Both nuclides exhibit their characteristic distributions. In the surface water, the exponential-like decrease of Ra-228 away from Baja California can be interpreted by horizontal water mixing with eddy diffusion coefficients (K-x) of 1 x 10(6) cm(2) s(-1) and 5 x 10(7) cm(2) s(-1) for scale lengths of 200 km and 1000 km, respectively. In the bottom waters, the decrease of Ra-228 away from bottom sediments can be modeled by vertical eddy diffusivities (K-z) of 15-30 cm(2) s(-1) except at one station (24 degrees 16.9' N, 115 degrees 8.9' W) where a value of 120 cm(2) s(-1) is... |
