Abstract
Tides play an important role in ocean energy transfer and mixing, and provide major energy for maintaining thermohaline circulation. This study proposes a new explicit tidal scheme and assesses its performance in a global ocean model. Instead of using empirical specifications of tidal amplitudes and frequencies, the new scheme directly uses the positions of the Moon and Sun in a global ocean model to incorporate tides. Compared with the traditional method that has specified tidal constituents, the new scheme can better simulate the diurnal and spatial characteristics of the tidal potential of spring and neap tides as well as the spatial patterns and magnitudes of major tidal constituents (K1 and M2). It significantly reduces the total errors of eight tidal constituents (with the exception of N2 and Q1) in the traditional explicit tidal scheme. Relative to the control simulation without tides, both the new and traditional tidal schemes can lead to better dynamic sea level (DSL) simulation in the North Atlantic, reducing significant negative biases in this region. The new tidal scheme also shows smaller positive bias than the traditional scheme in the Southern Ocean. The new scheme is suited to calculate regional distributions of sea level height in addition to tidal mixing.
Highlights
Diapycnal mixing plays a crucial role in the interior stratification of global oceans and meridional overturning circulation
The scheme uses the positional characteristics of the Moon and the Sun to calculate the tides directly instead of applying empirical specifications, such as the amplitudes and frequencies of tides, which were used in traditional methods
Compared with the traditional explicit eight tidal constituents scheme, we found that the new tidal scheme can better simulate the spatial characteristics of spring and neap tides
Summary
Diapycnal mixing plays a crucial role in the interior stratification of global oceans and meridional overturning circulation. The implicit form uses an indirect parameterization scheme that does not simulate the tides themselves (Laurent et al 2002) It enhances mixing, especially for deep seas and coastal areas, to represent the tidal effects. Especially for deep seas and coastal areas, to represent the tidal effects This type of mixing scheme was first applied in a coarse-resolution OGCM by Simmons et al (2004), and their results show that the biases of ocean temperature and salinity are substantially smaller. Saenko and Merryfield (2005) reported that this type of parameterization scheme contributes to the amplification of bottom-water circulation especially for the Antarctic Circumpolar Current and deep-sea stratification. The purpose of this study is to propose a new explicit tidal scheme in a CMIP6 class of OGCMs (Phase 6 of the Coupled Model Intercomparison Project) and assess its performance.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
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
