Interannual Variability of the South Atlantic Ocean Heat Content in a High‐Resolution Versus a Low‐Resolution General Circulation Model

Gronholz, A., Dong, S., Lopez, H., Lee, S. K., Goni, G., & Baringer, M. (2020). Interannual variability of the South Atlantic Ocean heat content in a high‐resolution versus a low‐resolution General Circulation Model. Geophysical Research Letters, e2020GL089908.

Plain Language Summary: In this study we analyze heat content changes of the upper South Atlantic Ocean and the impact of model resolution on these changes. Results from two numerical simulations are compared. One simulation with high‐resolution allows smaller‐scale processes directly, while the other simulation with low‐resolution does not. In both simulations oceanic heat transport dominates the ocean heat content changes on interannual time scale, while atmospheric fluxes play a secondary role. The heat anomalies, however, originate from different regions in the two simulations. While the oceanic heat transport from the south dominates in the high‐resolution simulation, oceanic heat transport from the north dominates in the low‐resolution simulation. Furthermore, wind‐induced surface heat transport plays a significant role in the low‐resolution while the heat transport in the high‐resolution simulation is dominated by changes in the ocean density field at depth. These results suggest fundamentally different driving mechanisms between the simulations and highlight the importance of model resolution to appropriately represent ocean dynamics in the South Atlantic Ocean and associated impacts on large‐scale climate.

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