Neodymium isotopes in the ocean model of the Community Earth System Model (CESM1.3)
Sifan Gu1, Zhengyu Liu1, Alexandra Jahn2, Johannes Rempfer3, Jiaxu Zhang1, and Fortunat Joos31Department of Atmospheric and Oceanic Sciences and Center for Climate Research, University of Wisconsin-Madison, Madison, 53705, USA 2Department for Atmospheric and Oceanic Sciences and Institude of Arctic and Alpine Research, University of Colorado Boulder, Boulder, 80309, USA 3Climate and Environmental Physics, Physics Institute and Oeschger Center for Climate Change Research, University of Bern, Bern, CH-3012, Switzerland
Received: 14 Feb 2017 – Accepted for review: 10 Mar 2017 – Discussion started: 13 Mar 2017
Abstract. Neodymium (Nd) isotope ratio (εNd) is a quasi-conservative water mass tracer and has been used increasingly as paleoclimate proxy to indicate the past evolution of ocean circulation. However, there are many uncertainties in interpreting εNd reconstructions. For the purposes of direct comparison between climate models and proxy reconstructions, we implement Nd isotopes (143Nd and 144Nd) in the ocean model of the Community Earth System Model (CESM). Two versions of Nd tracers are implemented: one is the "abiotic" Nd in which the particle fields are prescribed as the particle climatology generated by the marine ecosystem module of the CESM under present day forcing; the other is the "biotic" Nd that is coupled with the marine ecosystem module. Under present day climate forcing, our model is able to simulate both Nd concentrations and εNd in good agreement with available observations. Also, Nd concentration and εNd in our model show similar sensitivities to the total boundary source and the ratio between particle related Nd and dissolved Nd as in previous modeling study (Rempfer et al., 2011). Therefore, our Nd-enabled ocean model provides a promising tool to study past changes in ocean and climate.
Gu, S., Liu, Z., Jahn, A., Rempfer, J., Zhang, J., and Joos, F.: Neodymium isotopes in the ocean model of the Community Earth System Model (CESM1.3), Geosci. Model Dev. Discuss., doi:10.5194/gmd-2017-40, in review, 2017.