Reinterpretation of oceanic Th profiles based on decadal export productivity (2003-2010).

Understanding Th distributions in the global ocean is important to support and guide the use of this important radioactive nuclide in multiple aspects of oceanographic research, and this issue is now revisited. Based on estimates of export productivity (EP) over 2003-2010 and assuming Th scavenging at equilibrium at seven Pacific stations where linear Th profiles are found, an empirical equilibrium-state Th-scavenging versus EP correlation is established. This correlation demonstrates the relationship between Th-scavenging intensity and EP in the absence of advection. With this correlation, other Th profiles from global oceans are reinterpreted. My findings provide alternative explanations of signals carried by Th distributions with regard to advection, by a reassessment of the Th deficits in deep waters. Such an equilibrium-state Th-scavenging versus EP correlation provides a basis for convenient parameterization for use in 3D modeling studies of the Th distributions.