The AMOC at 47° North in Observations and a High Resolution Ocean Model

The Atlantic Meridional Overturning Circulation (AMOC) is the main driver of northward oceanic volume and heat transport in the Atlantic. Due to its definition via the streamfunction the exact calculation of the AMOC requires knowledge of the full velocity field. Since the early 2000s, observations of the AMOC are available at 47° North in the form of hydrographic sections across the Atlantic and continuous current measurements from moored instruments at specific locations. However, the spatial resolution of current measurements is coarse and shipbased hydrographic sections are mostly done only once a year. Also the observational timeseries still remain too short to come to conclusions about decadal trends in the AMOC variability. Thus, today our knowledge about the role of the AMOC in the global climate system is mainly based on model simulations. Comparing these model simulations against observations remains an important task to accurately predict the future of the AMOC and adapt to changes.

We present first results of a model observations comparison in the subpolar North Atlantic between observations at 47° North and the high resolution ocean model VIKING20X. The model has a 1/20° nest in the Atlantic embedded in a global 1/4° model. It covers the years from 1980 to 2018 and thus overlaps with the whole observational period. This comparison will help assessing different methods of estimating the AMOC strength from observations.