Comparison of ROMS and CROCO versions
=====================================

+----------------------+----------------------+----------------------+-----------------------+
| Models               | CROCO                | ROMS-UCLA            | ROMS-Rutgers / COASWT |
+======================+======================+======================+=======================+
| Origin               | UCLA-IRD-INRIA-      | UCLA                 | UCLA-Rutgers-USGS     |
|                      | IFREMER-SHOM-CNRS    |                      |                       |
+----------------------+----------------------+----------------------+-----------------------+
| Maintenance          | IRD-INRIA-IFREMER-   | UCLA                 | Rutgers-USGS          |
|                      | SHOM-CNRS            |                      |                       |
+----------------------+----------------------+----------------------+-----------------------+
| Realm                | Europe-World         | US West Coast        | US East Coast         |
+----------------------+----------------------+----------------------+-----------------------+
| Introductory year    | 1999 (AGRIF)         | 2002                 | 1998                  |
|                      | 2016 (CROCO)         |                      |                       |
+----------------------+----------------------+----------------------+-----------------------+

**CODE FEATURES**

+------------------------+---------------------------------------------+------------------------------------------+-------------------------------------------+
| Models                 | CROCO                                       | ROMS-UCLA                                |                   ROMS-Rutgers / COASWT   |
+========================+=============================================+==========================================+===========================================+
| Parallelization        | | MPI or OpenMP                             | Hybrid MPI-OpenMP                        | MPI or OpenMP                             |
|                        | | (Hybrid branch exists)                    |                                          |                                           |
+------------------------+---------------------------------------------+------------------------------------------+-------------------------------------------+                   
| Nesting                | | Online                                    | | Off-line (On-line at                   | Off-line                                  |
|                        | | at barotropic level                       | | baroclinic level and                   |                                           |
|                        |                                             | | not yet operational)                   |                                           |
+------------------------+---------------------------------------------+------------------------------------------+-------------------------------------------+
| Data assimilation      |3DVAR                                        | 3DVAR                                    | 4DVAR                                     |
+------------------------+---------------------------------------------+------------------------------------------+-------------------------------------------+
| Wave-current interact. | :cite:t:`mcwilliams_asymptotic_2004`        | :cite:t:`mcwilliams_asymptotic_2004`     | | :cite:t:`mellor_three-dimensional_2003` |
|                        |                                             |                                          | | :cite:t:`mcwilliams_asymptotic_2004`    |
+------------------------+---------------------------------------------+------------------------------------------+-------------------------------------------+
| Air-sea coupling       | OASIS-MCT                                   | Home made                                | MCT                                       |
+------------------------+---------------------------------------------+------------------------------------------+-------------------------------------------+
| Sediment Dynamics      | | :cite:t:`blaas_sediment-transport_2007`   | :cite:t:`blaas_sediment-transport_2007`  | | :cite:t:`blaas_sediment-transport_2007` |
|                        | | MUSTANG                                   |                                          | | :cite:t:`warner_development_2008`       |
+------------------------+---------------------------------------------+------------------------------------------+-------------------------------------------+
| Biogeochemistry        | | NPZD :cite:t:`gruber_eddy-resolving_2006`,| NPZD :cite:t:`gruber_eddy-resolving_2006`| | EcoSim, NEMURO,                         |
|                        | | PISCES                                    |                                          | | NPZD Franks,                            |
|                        |                                             |                                          | | NPZD Powell, Fennel                     |
+------------------------+---------------------------------------------+------------------------------------------+-------------------------------------------+
| Sea ice                | none                                        | none                                     | :cite:t:`budgell_numerical_2005`          |
+------------------------+---------------------------------------------+------------------------------------------+-------------------------------------------+
| Vertical mixing        | KPP, GLS                                    | KPP, GLS                                 | KPP, GLS                                  |
+------------------------+---------------------------------------------+------------------------------------------+-------------------------------------------+
| Wetting-Drying         | :cite:t:`warner_wetting_2013`               | none                                     | :cite:t:`warner_wetting_2013`             |
+------------------------+---------------------------------------------+------------------------------------------+-------------------------------------------+

**TIME STEPPING**

+----------------------+---------------------------+---------------------------+----------------------------------+
| Models               | CROCO                     + ROMS-UCLA                 + ROMS-Rutgers / COASWT            +
+======================+===========================+===========================+==================================+
| 2D momentum          | Generalized FB AB3-AM4    | Generalized FB AB3-AM4    | LF-AM3 with FB feedback          |
+----------------------+---------------------------+---------------------------+----------------------------------+
| 3D momentum          + LF-AM3                    + LF-AM3                    + AB3                              +
+----------------------+---------------------------+---------------------------+----------------------------------+
| Tracers              | | LF-AM3 with stabilizing | | LF-AM3 with stabilizing | | LF-TR with explicit            |
|                      | | correction for isopycnal| | correction for isopycnal| | geopotential diffusion         |
|                      | | hyperdiffusion          | | hyperdiffusion          | | (no stabilizing correction :   |
|                      |                           |                           | | strong stability constraint)   |
+----------------------+---------------------------+---------------------------+----------------------------------+
| Internal waves       | LF-AM3 with FB feedback   | LF-AM3 with FB feedback   | Generalized FB (AB3-TR)          |
+----------------------+---------------------------+---------------------------+----------------------------------+
| Coupling stage       | Predictor                 | Corrector                 |                                  |
+----------------------+---------------------------+---------------------------+----------------------------------+

**STABILITY CONSTRAINTS (Max Courant number)**

======================= ======================= ======================= =======================
Models                  CROCO                   ROMS-UCLA               ROMS-Rutgers / COASWT
======================= ======================= ======================= =======================
2D                      1.78                    1.78                    1.85
3D advection            1.58                    1.58                    0.72
Coriolis                1.58                    1.58                    0.72
Internal waves          1.85                    1.85                    1.14
======================= ======================= ======================= =======================