Abstract
Abstract. This paper describes the implementation of a coupling between a three-dimensional ocean general circulation model (NEMO) and a wave model (WW3) to represent the interactions of upper-oceanic flow dynamics with surface waves. The focus is on the impact of such coupling on upper-ocean properties (temperature and currents) and mixed layer depth (MLD) at global eddying scales. A generic coupling interface has been developed, and the NEMO governing equations and boundary conditions have been adapted to include wave-induced terms following the approach of McWilliams et al. (2004) and Ardhuin et al. (2008). In particular, the contributions of Stokes–Coriolis, vortex, and surface pressure forces have been implemented on top of the necessary modifications of the tracer–continuity equation and turbulent closure scheme (a one-equation turbulent kinetic energy – TKE – closure here). To assess the new developments, we perform a set of sensitivity experiments with a global oceanic configuration at 1/4∘ resolution coupled with a wave model configured at 1/2∘ resolution. Numerical simulations show a global increase in wind stress due to the interaction with waves (via the Charnock coefficient), particularly at high latitudes, resulting in increased surface currents. The modifications brought to the TKE closure scheme and the inclusion of a parameterization for Langmuir turbulence lead to a significant increase in the mixing, thus helping to deepen the MLD. This deepening is mainly located in the Southern Hemisphere and results in reduced sea surface currents and temperatures.
Highlights
An accurate representation of ocean surface waves has long been recognized as essential for a wide range of applications from marine meteorology to ocean and coastal engineering
While the Axell (2002) parameterization was already implemented in Nucleus for European Modelling of the Ocean (NEMO), there are three major novelties in our implementation: (i) the online coupled strategy allows us to use the surface Stokes drift directly delivered by the wave model instead of the original value empirically estimated from the wind speed (e.g., 1.6 % of the 10 m wind). (ii) We only considered the component of the Stokes drift aligned
In this paper we have described the implementation of an online coupling between the oceanic model NEMO and the wave model WW3
Summary
An accurate representation of ocean surface waves has long been recognized as essential for a wide range of applications from marine meteorology to ocean and coastal engineering. Belcher et al (2012) showed that Langmuir turbulence should be important over wide areas of the global ocean, more in the Southern Ocean In this region, they show that the inclusion of the effect of surface waves on the upper-ocean mixing during summertime allows for a reduction of systematic biases in the OSBL depth. The objective is to introduce a new online two-way-coupled ocean– wave modeling system with great flexibility to be relevant for a large range of applications from climate modeling to regional short-term process studies This modeling system is based on the Nucleus for European Modelling of the Ocean (NEMO; Madec, 2012) as the oceanic compartment and WAVEWATCH III® (hereinafter WW3; WAVEWATCH III® Development Group, 2016) as the surface wave component.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
