Output File Format

Model outputs are saved using the netCDF4 file format.

Gridded Variables

In any given run, the saving parameters “save_<var>_grids” control whether or not that 2-D grid variable (e.g. velocity) is saved to the netCDF4 file. In the netCDF4 file, a 3-D array with the dimensions time x length x width is created for each 2-D grid variable that is set to be saved. The appropriate units for these variables are stored as well, such as “meters per second” for the velocity grid.

Grid Coordinates

To save the model information associated with the domain itself, variables associated with the grid are saved as well. These are the meshed 2-D grids corresponding to the distance of each cell from the boundary in the “Width” dimension of the domain, x in meters. As well as the distance away from the boundary of each cell in the “Length” dimension, as y in meters. Similarly, a time variable is stored which is a 1-D array (vector) holding the model time values in seconds, associated with each set of saved output data.

Model Metadata

In addition to the grid coordinates, model metadata is saved as a group of 1-D arrays (vectors) and 0-D arrays (floats and integers). The values that are saved as metadata are the following:

  • Length of the land surface: L0

  • Width of the inlet channel: N0

  • Center of the domain: CTR

  • Length of cell faces: dx

  • Depth of inlet channel: h0

  • Sea level: H_SL

  • Bedload fraction: f_bedload

  • Sediment concentration: C0_percent

  • Characteristic Velocity: u0

  • If subsidence is enabled:
    • Subsidence start time: start_subsidence

    • Subsidence rate: sigma

Working with Model Outputs

The resulting netCDF4 output file can be read using any netCDF4-compatible library. These libraries range from the netCDF4 Python package itself, to higher-level libraries such as xarray. For deltas, and specifically pyDeltaRCM, there is also a package under development called DeltaMetrics, that is being designed to help post-process and analyze pyDeltaRCM outputs.