Development and Implementation of a Langmuir Turbulence Parameterization
Abstract
Langmuir turbulence (LT) occurs under the influence of wave and wind forcing, which arises as an additional vortex force in the momentum equations according to the theory of Craik and Leibovich (1976). Although LT is now regarded as a contributing and often dominant factor driving turbulent processes that transport heat and momentum in the upper layer of oceans and lakes, our understanding on this physical process is still limited. Current attempts to represent the LT effect in ocean models are all based on idealized study with simplified oceanic and wind conditions, and thus can have limited practical application in real ocean modeling. This report describes the development of a parameterization that represents the eddy viscosity difference due to the presence of LT based on real case studies, and its implementation in the Navy Coastal Ocean Model (NCOM). The new parameterization overcomes two significant limitations by previous attempts that presume wind-wave alignment and constant Stokes depth penetration ratio (). The model proposed here includes an additional function to account for the wind-wave angle of misalignment and variable Stokes decay scales base on real case simulations. Although model comparisons at the Ocean Weather Station Papa show comparable skill between the newly developed parameterization and the turbulence closure models by Kantha-Clayson (2004) and Harcourt (2015), given the relative simple ocean dynamics at the station, we expect better performance from the new parameterization in more complicated atmospheric and ocean conditions.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 28, 2019
- Accession Number
- AD1089901
Entities
People
- Miguel Solano
- Paul J. Martin
- Yalin Fan
Organizations
- United States Naval Research Laboratory