Global distribution of the 230Th £ux to ocean sediments constrained by GCM modelling, Deep-Sea Res

• Main Authors: Gideon M. Henderson, Christoph Heinze, Robert F. Anderson, Arne M. E. Winguth
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1999
• Subjects: Weddell; Weddell Sea
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.591.9940; http://www.earth.ox.ac.uk/~gideonh/pdffiles/230Th.pdf

We have introduced a simple particle "eld into an existing and well-documented ocean general circulation model. This enables us to investigate the advection and scavenging of particle-reactive species within the water column. As a "rst use of this model, we have assessed the advection and #ux to sediment of 230Th, a nuclide with a well understood marine chemistry that exhibits extreme particle reactivity. The #ux to sediment of this nuclide is of interest as it is widely assumed to be related only to water depth, and therefore to act as a constant-#ux indicator for marine sediments. By assuming an average settling velocity for marine particles of 3 m/d, in good agreement with observational constraints, the model generates a particle "eld close to that observed. Thorium-230 is scavenged onto this particle "eld reversibly according to Kd values constrained by observations and incorporating a particle-concentration e!ect. This scavenging gives a good "t to the +900 literature water-column measurements of 230Th suggesting that the model is advecting and removing 230Th realistically. An exception to this is the Weddell Sea, where the model has too little ice cover and too much lateral mixing, which prevents it from duplicating the observed high 230Th values. The model con"rms that signi"-