CoCOMA

Coastal and Continental Ocean Model of Australia (CoCOMA) is CSIRO’s 3D national COMPAS marine model, extending from the coast to beyond the continental shelf. It is based on the finite volume COMPAS numerical model, developed by the Coastal Environmental Modelling team (CEM) and operates on a variable resolution unstructured mesh. It includes the effects of tides (TPXO), atmospheric conditions (ACCESS) of sea-level pressure, solar radiation, air temperature and rainfall and nests within the Bluelink global ocean model to capture large scale ocean dynamics at the boundaries. These broader scale dynamics are further resolved by the model via simulation of barotropic and baroclinic physical processes at higher resolution in the interior of the model that generate features at meso and sub-meso scales.

Future plans include the incorporation of a sediment transport model as well as ecological processes. Fresh water inputs from major rivers will be added soon.

Model versions

Versions are indicative of the nominal cell resolution at the coast. Each of these have the same spatial extent but balance the physical processes needed to resolve particular science applications versus the computational burden. Mesh weighting is based on distance from coast. There are 54 z-layers in the vertical.

Version	Max. cell resolution at the coast / Min. cell resolution at Open Boundary (m)	2D Surface / Total 3D cells (approx.)	Link to pilot model data on THREDDS	Download mesh GIS layer (includes Mesh2_depth attribute)
1K	130 / 13 K	1.45 M / 21 M	available soon	cocoma-1k-mesh.geojsonl.json
2K	350 / 28 K	4.3 K / 6.4 M	CoCOMA-2K	cocoma-2k-mesh.geojsonl.json
5K	700 / 14 K	1.3 K / 2.5 M	available soon	cocoma-5k-mesh.geojsonl.json

 

An example parameter file can be found  here: cocoma_2k.prm

Mesh details – 2K

Model analysis and visualisation

The emsarray python package may be used interrogate the model data directly from the OpenDAP URL’s available from the above THREDDS server. It’s an extension to xarray, allowing users to very quickly create 2D plots on a map, point extractions for time series and depth profiles.

Zoomed animations

The following animations have been extracted from the CoCOMA-2K pilot model data

Port Phillip bay regions, VIC

Keppel bay region, QLD

North West shelf sub-region, WA

Tiled model domains

The CoCOMA 1K mesh has been further divided up into tiled domains. These are exact sub-regions of the larger mesh, allowing independent model execution to reduce the computational burden during the configuration and calibration/validation stages. These regional parameterisations can then be directly applied to the full mesh. These may also be used for specific science studies as applicable for that region and project.

A couple of examples are shown below.

South East (SE) tile

Great Barrier Reef (GBR) tile

Further information

For more details please refer to this technical report : CoCOMA Technical report

Note: This project is very much in-progress, information on this web page as well as the report above will be updated periodically

Contact : farhan.rizwi@csiro.au