Open-Ocean Tides Simulated by ICON-O

Abstract

Abstract. This paper evaluates barotropic tides simulated by a newly developed ocean general circulation – ICON-O and assesses processes and model configurations that can impact the quality of the simulated tides. Such an investigation is crucial for applications addressing internal tides that are much more difficult to evaluate than the barotropic tides. Although not specially tuned for tides and not constrained by any observations, ICON-O is capable of producing the main features of the open-ocean barotropic tides as described by the geographical distributions of amplitude, phase, and amphidromic points. An error analysis shows however that the open-ocean tides simulated by ICON-O are less accurate than those simulated by two other OGCMs. Using a suite of tidal experiments we show that an increase in horizontal resolution improves only tides in shallow waters. Relevant for using ICON-O with its telescoping grid capacity, we show that spatial inhomogeneity does not deteriorate the quality of the simulated tides. We show further that implementing a parameterization of tidal bottom drag improves the quality of simulated tides, independent of model configuration used.