Water isotope variations in the global ocean model MPI-OM

• Published in: Geoscientific Model Development
• Main Authors: Xu, X., Werner, M., Butzin, M., Lohmann, G.
• Format: Text
• Language: English
• Published: 2018
• Subjects: Arctic
• Online Access: https://doi.org/10.5194/gmd-5-809-2012; https://gmd.copernicus.org/articles/5/809/2012/

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.