An accurate implementation of the compressibility terms in the equation of state in a low order pressure gradient scheme for sigma coordinate ocean models

作者：Marsaleix Patrick^*; Auclair Francis; Estournel Claude; Cyril Nguyen; Ulses Caroline

来源：Ocean Modelling, 2011, 40(1): 1-13.

DOI：10.1016/j.ocemod.2011.07.004

• Pressure gradient
• Sigma coordinate
• Equation of state
• Compressibility
• Seamount
• Pressure Jacobian

In a previous study, the authors studied a low order pressure gradient force (PGF) scheme referred to as the Primitive-Modified scheme, that appears to be equivalent to the Pressure-Jacobian PGF (Lin, 1997). The scheme was successfully tested on the seamount experiment using a simplified equation of state (EOS). Yet, a complete equation of state, including compressibility effect, can raise a serious problem of accuracy. A new implementation is thus proposed in the present paper. The scheme is rewritten using a (numerically equivalent) geopotential formulation. The PGF truncation errors are removed by computing the EOS compressibility terms with potential temperature and salinity interpolated on a suitable geopotential level. The so-called Equivalent Geopotential Formulation (EGF) method is compared to the Finite-Volume approach proposed by Adcroft et al. (2008).

• 出版日期2011