A nonhydrostatic oceanic regional model ORCTM v1 for 1 internal solitary wave simulation 2

. 7 An Oceanic Regional Circulation and Tide Model (ORCTM version 1) including the nonhydrostatic 8 dynamics module which can numerically reproduce the Internal Solitary Waves (ISWs) dynamics, is 9 presented in this paper. The model open boundary conditions are also supportive of regional baroclinic 10 tidal wave simulations. 11 The incompressible Boussinesq equations in z-coordinates consider the three-dimensional and fully 12 nonlinear forms. The pressure field is also decomposed into the surface, hydrostatic and nonhydrostatic 13 components on the orthogonal curvilinear Arakawa-C grid. The nonhydrostatic pressure determined by 14 the intermediate velocity divergence field is obtained via solving a three-dimensional Poisson equation 15 based on a pressure correction method. Model validation experiments for ISWs simulations with the 16 topographic change in the two-layer and continuously stratified ocean demonstrate that the ORCTM has 17 a considerable capacity for reproducing the life cycle of Nonlinear Internal Waves evolution and tide- 18 topography interactions. 19 reflected waves including 342 a series of elevation tail waves, are released at x = 1.6 m. In detail, the first elevation is the leading one 343 with the rank-ordered structure in the rear all propagating to the west. After reaching the deep-water zone 344 left to 1.3 m, the wave rear begins to steepen and sink, generating a depression wave behind it. Namely, 345 the soliton wave passes the critical point inversely as a consequence of the water deepening. -1 a double-peak structure distributed at the depths of 150 602 and 1000 m the vertical velocity the strength in the deep layer is than the 603 upper’s, in smaller isotherm fluctuation above 200 m. the Taylor-Goldstein equation 604 the eigenfunction the vertical velocity 21d. The second-mode 605 eigenvalues have two peaks in vertical direction whose depths correspond to 150 and 1070 m with the 606 latter strength stronger than the former, and the corresponding phase speed is about 1.34 m s -1 . The above 607 theoretical results can compare well with the distribution of stimulated characteristics, indicating that our 608 nonhydrostatic ocean model succeeds in describing the nonlinear evolution of higher modal baroclinic