Model Description

The newly developed TIMCOM is a robust, efficient, accurate, and user-friendly model for studying ocean flow problems. Major features of TIMCOM are summarized as follows.

Hydrostatic or non-hydrostatic pressures:
TIMCOM solves the unsteady, incompressible, 3D primitive equations with Boussinesq and hydrostatic approximations on a full spherical coordinate. For the applications with rapidly changed bathymetry or density inversion, non-hydrostatic version ( Dietrich & Lin,2002) is required and available under licensing agreement.
Nonlinear equation of state:
A standard nonlinear equation of state is used to calculate in-situ density in terms of potential temperature, salinity and pressure-depth.
Turbulence mixing (Viscosity & Diffusivity):
Weakly physical-based parameterization is used for the horizontal mixing. For the vertical mixing, TIMCOM employs the approach of Pacanowski & Philander (1981), instead of computation- and storage-intensive Mellor-Yamada level 2.5 turbulence closure in SOMS model ( Dietrich et al., 1987). The users can also apply any preferred scheme.
Non-damping surface nudging:
An precise surface flux treatment (Dietrich et al., 2004b) which does not damp transients and gives rapid convergence to ensemble average annual cycle climatology is utilized. It may be used in combination with synoptic wind and surface flux forcing.
Highly-accurate and low-dissipative numerical scheme:
TMCOM uses a blend of collocated and staggered grid structure with non-uniform grid increments. Second-order Leap-frog temporal scheme and fourth-order-accurate spatial discretization (or interpolation) are applied to discretize the governing equations. Further, modified Robert-Asselin filter with high accuracy are employed.
Efficient pressure Poisson solver:
Efficient and accurate Error Vector Propagation (EVP) solver is used to solve the system matrix. EVP solver is also ideal and suitable for parallel computing ( Tseng & Chien,2011).
Flux-conserved grid coupling algorithm:
Simple, efficient, stable, and flux-conserved grid coupling algorithm (Dietrich et al., 2004b) facilitates multi-scale dynamics modeling with a greatly reduced computational cost.
Particle tracking:
TIMCOM now has the capability to release tracers from a specified location for particle tracking.
Code Structure:
TIMCOM is written in Fortran 90 programming language with a modular approach, which makes future modification (or improvement) of the code simple and easy. TIMCOM supports Intel and pgi compilers and can work on Windows or Unix system.

The hydrostatic, rigid-lid approximation version of TIMCOM is now released and available on the website The related pages will briefly express the governing equations, numerical methods, grid coupling algorithm, code structure, and the model execution. Currently, several advanced features such as (i) immersed boundary methods for topography, (ii) turbulence parameterization options, (iii) hindcast wind forcing capability, (iv) ensemble simulation capability, (v) bio-geochemistry dynamics are under development and will be reported in the near future.