Application of wave‐induced vertical mixing to the K profile parameterization scheme

Abstract

Surface‐wave‐induced vertical mixing is incorporated to modify the K profile parameterization (KPP) scheme. The effects of this modified KPP scheme on a quasi‐global oceanic general circulation model are examined by carrying out four test cases. To evaluate simulated upper layer temperature and surface mixed‐layer depth (MLD), the model seasonal cycle of temperature and MLD are compared with those from Levitus climatology. In this study, the MLD is defined as the depth that the temperature has changed 0.8°C from the reference depth of 10 m. Statistic analysis shows that test cases with the addition of wave‐induced vertical mixing can reduce the root‐mean‐square difference of upper layer temperature and increase the correlation with Levitus climatology. On the basis of the comparison with Levitus climatology, the surface‐wave‐induced mixing improves the simulation of MLD in summertime for both hemispheres. Comparing the MLD in different seasons, the wave‐induced mixing improves MLD in both hemispheres in summer more than in other seasons. The simulation results are sensitive to weighting coefficients of the wave‐induced mixing, suggesting that a preferred weighting coefficient be between 0.1 and 0.3 in the modified KPP scheme.