Water isotope variations in the global ocean model MPI-OM

• Published in: Geoscientific Model Development
• Main Authors: X. Xu, M. Werner, M. Butzin, G. Lohmann
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2012
• Subjects: Geology; QE1-996.5; Arctic
• Online Access: https://doi.org/10.5194/gmd-5-809-2012; https://doaj.org/article/87eba57ba4e548e2a2617a85e2a9208d

The stable water isotopes H 2 18 O and HDO are incorporated as passive tracers into the oceanic general circulation model MPI-OM, and a control simulation under present-day climate conditions is analyzed in detail. Both δ 18 O and δD distributions at the ocean surface and deep ocean are generally consistent with available observations on the large scale. The modelled δD-δ 18 O relations in surface waters slightly deviates from the slope of the global meteoric water line in most basins, and a much steeper slope is detected in Arctic Oceans. The simulated deuterium excess of ocean surface waters shows small variations between 80° S and 55° N, and a strong decrease north of 55° N. The model is also able to capture the quasi-linear relationship between δ 18 O and salinity S , as well as δD and S , as seen in observational data. Both in the model results and observations, the surface δ− S relations show a steeper slope in extra-tropical regions than in tropical regions, which indicates relatively more addition of isotopically depleted water at high latitudes.