Model setup methodology

NOTE: This article has been discontinued and is no longer maintained.

This is the log of the current best-practice methodology for setting up hydrodynamic nested models.

Build the General Data

Bathymetries

• Grid: First of all, define your domain(s) and build the grid(s). We use Mohid GIS for that matter. For nested models, remember to keep a maximum downscaling factor ratio of 1:3. In the end, you should have a bunch of .grd files.

• Baseline data: Next, you need to define/obtain your baseline topographic/bathymetric data as well as your landline data. For example, in regional oceanography, one could choose the ETOPO or GEBCO datasets (available in intranet at \\kepler\DataCenter\DadosBase\Oceanografia\Batimetria) for the bathymetry.

• ConvertToXYZ: However, before interpolation of the datasets to your grid, you need to convert the dataset into a readable file for Mohid GIS. ConvertToXYZ is a little program used for that effect. It will create a .xyz file.

• Digital Terrain Creator: Create land line and save it as a .xy file. Interpolate the bathymetry data .xyz file to your grid by using the Digital Terrain Creator software.

• SmoothBatimNesting: Optionally, if you created a son grid, then you'll want to smooth it near the boundaries relatively to the father grid. We use the SmoothBatimNesting software for that matter.

• Retouch manually the bathymetry .dat file(s) under Mohid GIS in order to remove all awkward looking cells, as they tend to be a nuisance for stability issues later on.

That's it, your bathymetries should be ready to go!

Tidal gauges

To simulate tide, MOHID generates the tide water level at the boundaries by interpolation of predicted levels between points defined near the open boundaries of the domain. The predicted levels are calculated by the TidePrev software embedded in MOHID. TidePrev calculates the water level from the tidal harmonic components. The harmonic components are given by the Fes95 or the Fes2004 solution, and tidal gauges can be extracted for points near the boundary. Thus MOHID requires the tidal gauges. The tidal gauges are obtained by the Fes95 or Fes2004 software. The input for the Fes2004 software is an .xyz file.

Initial S and T fields

S and T fields are waterproperties. Mohid allows several ways to initialize S and T.

• PROFILE
• LAYERS
• ASCII_FILE
• etc...

You should refer to waterproperties.dat to learn how to initialize S and T.