Using A Inertial Internal Wave Breaking Mixing Scheme To Improve The LICOM Model

Owing to the important effect of the ocean on the climate system, oceanic general circulation model (OGCM) is an extremely important part of coupled ocean-atmosphere general circulation models. The study of ocean interior mixing plays a key role in improving and developing OGCM. With the development of the observation technology, the rapid development of the ocean interior mixing is attained by oceanographers. The process of ocean internal energy transmission becomes increasingly clear. Vertical mixing process in ocean, such as fine structure, is one of the most important parts of ocean interior mixing. In the ocean general circulation model (OGCM), the parameterization of vertical mixing (or diapycnal mixing) in the ocean interior is a key issue.Based on the theoretical spectral model of inertial internal wave breaking (fine structure) proposed previously, in which the effects of the horizontal Coriolis frequency component f-tilde on a potential isopycnal are taken into account, Fan et al. put forward a inertial internal wave breaking mixing scheme. In this paper, in the framework of the LICOM (LASG/IAP Climate System Ocean Model) we use two schemes of vertical mixing in the OGCM respectively, that is, the turbulence mixing scheme of Canuto et al. (T-scheme for short) in 2010 alone, and adding the inertial internal wave breaking mixing scheme(F-scheme for short) put forward recently by Fan et al.(2015) in the OGCM except the region from 15°S to 15°N. In order to study the effect of the inertial internal wave breaking mixing scheme on OGCM, we compare and analyze the result of two experiment.The comparison and analysis of the experiment results indicate that:(1)A notable improvement in the simulation of salinity and temperature over the global ocean is attained by using T-scheme adding F-scheme, especially in the mid-and high-latitude regions in the simulation of the Intermediate Water and Deep Water, and the biggest improvement value on the depth of the average temperature is 0.2 ℃;(2)The modeling strength of the Atlantic Meridional Overturning Circulation (AMOC) by using T-scheme adding F-scheme may be more reasonable than that by using T-scheme alone;(3)A great amelioration in the simulation of the Atlantic Water Core Temperature (AWCT) and its depth in the Arctic Ocean is obtained;(4) The simulation of meridional density difference decreases, especially between northern high latitude region and the tropics;(5)A shortcoming in F-scheme is that in this paper the error of simulated salinity and temperature by using T-scheme adding F-scheme is larger than that by using T-scheme alone in the subsurface layer.