Title: Modeling Neodymium Isotopes in the Ocean Component of the Community Earth System Model (CESM1)

Abstract

Neodymium (Nd) isotopic composition (ε_Nd) is an important tracer for water mass mixing and the reconstruction of past ocean circulation. To allow for a direct model-data comparison, we have implemented Nd isotopes in the ocean component of the Community Earth System Model (CESM1.3). The model is able to capture the major features of the observed modern distribution of both ε_Nd and Nd concentrations. Our model provides a useful tool for the interpretation of ε_Nd reconstructions. For example, we show that in an idealized North Atlantic freshwater hosing experiment, ε_Nd changes in the Atlantic are documenting primarily the changes in water mass mixing and are hardly affected by the concomitant and large changes in the marine biological productivity and organic matter fluxes. However, the hosing experiment also shows that the end-member changes due to the change of ocean circulation can influence the interpretation of ε_Nd in the Atlantic, depending on the location. The implementation of Nd, together with other existing tracers, such as δ¹⁸O, ²³¹Pa/²³⁰Th, δ¹³C, and radiocarbon in the same model, can improve our understanding of past ocean circulation significantly.

Authors:

Gu, Sifan  ^[1];

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Liu, Zhengyu ^[2]; Jahn, Alexandra  ^[3];

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Rempfer, Johannes ^[4]; Zhang, Jiaxu  ^[5];

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Joos, Fortunat  ^[4]

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+ Show Author Affiliations

1. Department of Atmospheric and Oceanic Sciences, University of Wisconsin-Madison, Madison WI USA, Now at Physical Oceanography Laboratory, Ocean University of China, Qingdao China
2. Atmospheric Science Program, Department of Geography, The Ohio State University, Columbus OH USA
3. Department for Atmospheric and Oceanic Sciences and Institute of Arctic and Alpine Research, University of Colorado Boulder, Boulder CO USA
4. Climate and Environmental Physics, Physics Institute and Oeschger Center for Climate Change Research, University of Bern, Bern Switzerland
5. Computational Physics and Methods (CCS-2) and Center for Nonlinear Studies (CNLS), Los Alamos National Laboratory, Los Alamos NM USA

Publication Date:

2019-03-04

Research Org.:

Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Sponsoring Org.:

USDOE Laboratory Directed Research and Development (LDRD) Program

OSTI Identifier:

1497749

Alternate Identifier(s):

OSTI ID: 1497750; OSTI ID: 1499368

Report Number(s):

LA-UR-19-21453
Journal ID: ISSN 1942-2466

Grant/Contract Number:  

SC0006744; 89233218CNA000001

Resource Type:

Published Article

Journal Name:

Journal of Advances in Modeling Earth Systems

Additional Journal Information:

Journal Name: Journal of Advances in Modeling Earth Systems; Journal ID: ISSN 1942-2466

Publisher:

American Geophysical Union (AGU)

Country of Publication:

United States

Language:

English

Subject:

58 GEOSCIENCES; Nd isotopes; isotope modelling; CESM