Sarmiento, J. L., C. G. H. Rooth, and W. S. Broecker, 1982: Radium 228 as a tracer of basin wide processes in the abyssal ocean. Journal of Geophysical Research, 87 (C12), 9694-9698.

Abstract: A simple model of isopycnal mixing in a circular basin is developed in order to examine the utility of the 5.75-year half-life tracer radium 228 for studying basin wide processes in the deep ocean. The model shows that it is possible to resolve diffusivities of approximately less than 8 x 10⁷ cm² s^-1 in a basin of ~3000-km diameter with profiles measured near the center and edge of the basin. A least squares fit of the model to four abyssal profiles measured during GEOSECS in the North Atlantic Basin gives an isopycnal diffusivity of 6 x 10⁷ cm² s^-1.