Implementation of a Hybrid Surface Layer Parameterization Scheme for the Coupled Atmosphere-Ocean Wave System WEW

Abstract

The two-way fully coupled atmosphere-ocean wave system WEW has been recently developed for studying the factors that contribute to the air-sea interaction processes and feedbacks. The new developed wind-wave parameterization scheme reduces both the near surface wind speed and the significant wave height as a response to the increased aerodynamic drag considered by the atmospheric model over rough sea surfaces. Such behavior is mainly attributed to the surface layer parameterization scheme of the atmospheric component which is based on the Mellor-Yamada-Janjic (MYJ) scheme. Therefore, we proceed to develop a new hybrid surface layer parameterization based on the MYJ and the Janssen schemes that operate in the atmospheric and ocean wave components of the WEW, respectively. In this case the roughness length depends on the wave age instead of the Charnock parameter following the formulation proposed by Drennan et al. (2003). The parameterization of the viscous sublayer and the universal functions for the estimation of the near surface wind speed have been accordingly revised. The new hybrid scheme has been statistically evaluated against buoys measurements and satellite retrievals across the Mediterranean Sea in a case study of high-impact weather and sea state event.