We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Simulating marine neodymium isotope distributions using ND v1.0 coupled to the ocean component of the FAMOUS-MOSES1 climate model: sensitivities to reversible scavenging efficiency and benthic source distributions.
- Authors
Robinson, Suzanne; Ivanovic, Ruza; Gregoire, Lauren; Tindall, Julia; van de Flierdt, Tina; Plancherel, Yves; Pöppelmeier, Frerk; Tachikawa, Kazuyo; Valdes, Paul
- Abstract
The neodymium (Nd) isotopic composition of seawater is a widely used ocean circulation tracer. However, uncertainty in quantifying the global ocean Nd budget, particularly constraining elusive non-conservative processes, remains a major challenge. A substantial increase in modern seawater Nd measurements from the GEOTRACES programme coupled with recent hypotheses that a seafloor-wide benthic Nd flux to the ocean may govern global Nd isotope distributions (eNd) presents an opportunity to develop a new scheme specifically designed to test these paradigms. Here, we present the implementation of Nd isotopes (143Nd and 144Nd) into the ocean component of the FAMOUS coupled atmosphere-ocean general circulation model (ND v1.0), a tool which can be widely used for simulating complex feedbacks between different Earth system processes on decadal to multi-millennial timescales. Using an equilibrium pre-industrial simulation tuned to represent the largescale Atlantic Ocean circulation, we perform a series of sensitivity tests evaluating the new Nd isotope scheme. We investigate how Nd source/sink and cycling parameters govern global marine eNd distributions, and provide an updated compilation of 6,048 Nd concentration and 3,278 eNd measurements to assess model performance. Our findings support the notions that reversible scavenging is a key process for enhancing the Atlantic-Pacific basinal eNd gradient, and is capable of driving the observed increase in Nd concentration along the global circulation pathway. A benthic flux represents a major source of Nd to the deep ocean. However, model-data disparities in the North Pacific highlight that the source of eNd from seafloor sediment is too unradiogenic in our model with a constant benthic flux. Additionally, model-data mismatch in the northern North Atlantic suggests a missing source of Nd that is much more unradiogenic than the bulk sediment, alluding to the possibility of preferential contributions from 'reactive' detrital sediments under a benthic flux driven model of marine Nd cycling. The new Nd isotope scheme forms an excellent tool for exploring global marine Nd cycling and the interplay between climatic and oceanographic conditions under both modern and palaeoceanographic contexts.
- Subjects
NEODYMIUM isotopes; ATMOSPHERIC models; GENERAL circulation model; OCEAN; SEAWATER composition; OCEAN circulation; CLIMATE sensitivity
- Publication
Geoscientific Model Development Discussions, 2022, p1
- ISSN
1991-9611
- Publication type
Article
- DOI
10.5194/egusphere-2022-606