More realistic oceanic particle field improved the thorium-230 and protactinium-231 modeling

Thorium-230 (230Th) and protactinium-231 (231Pa) are two geochemical tracers extensively used for investigating particle transport in the ocean and reconstructing past ocean circulation. A key feature in reproducing their distributions by modelling is to understand and constrain as good as possible the scavenging processes, which means: 1) having the good adsorption-desorption kinetic rates and 2) describing the up to date best particle field. The later was challenged by the NEMO-PISCES team who considerably improved the particle field description of the NEMO-PISCES model. This recent development allowed van Hulten and co-workers (2018, see reference below) to propose a new simulation of 230Th and 231Pa using a version called NEMO-ProThorP 0.1 in which the dust lithogenic particles were added. Although nepheloid and hydrothermal particles are still missing to better simulate the particle field this new version provides satisfying distributions of both tracers. Thanks to the GEOTRACES field database, comparison of the model results to the measured ones shows more realistic partition coefficients than what was simulated so far. Although further improvements are still needed, this work is an important step forward in our understanding of these tracer behaviors in the ocean.

18 vanHulten l

Figure: Modelled dissolved thorium-230 activity at four depth level (mBqm−3 ); observations are represented as discs on the same colour scale. Click here to view the figure larger.

Reference:

van Hulten, M., Dutay, J.-C., & Roy-Barman, M. (2018). A global scavenging and circulation ocean model of thorium-230 and protactinium-231 with improved particle dynamics (NEMO–ProThorP 0.1). Geoscientific Model Development, 11(9), 3537–3556. DOI: http://doi.org/10.5194/gmd-11-3537-2018

Latest highlights

Science Highlights

Quantifying the weathered fluxes to the ocean is far from over: the overlooked role of rock coast erosion

This study reveals that cliff derived sediment supply is only three times less than the solid discharge of rivers for Europe.

21.01.2022

Science Highlights

Contrasting distributions of dissolved manganese, nickel, cadmium and zinc in the Mediterranean Sea

Extensive trace metal clean sampling during the Dutch GEOTRACES cruise in the Mediterranean Sea allowed Middag and his colleagues to establish the basin scale distribution of these trace metals.

19.01.2022

Science Highlights

Specific features characterize the dissolved iron distribution in the North Western Indian Ocean

Venkatesh Chinni and Sunil Kumar Singh propose dissolved iron profiles along two meridional transects realized during spring and fall seasons between the Arabian Sea and the sub-tropical western Indian Ocean…

07.01.2022

Science Highlights

Anthropogenic aerosol has become a dominant source of zinc in the deep water of the Northern South China Sea

Liao and colleagues determined zinc concentrations and isotope compositions in sinking particles collected in the Northern South China Sea…

24.11.2021

Rechercher