AUBELLHOP: environment configuration options

Each Bellhop simulation is driven by its so-called environment configuration file. This is created by aubellhop based on the setup of the respective Environment class. This page details each of the fields/options that can be set in the class.

See the environment configuration page for general methods of setting up the class.

1 Simulation extent

    simulation_depth: float
    simulation_range: float
    simulation_cross_range: float

These parameters set the absolute value of the boundaries of the Bellhop simulation. They default to a scaling factor of the maximum relevant dimension:

  • simulation_depth is based on the bathymetry
  • simulation_range is based on the furthest receiver range
  • simulation_cross_range is based on the component of the largest bearing angle and the furthest receiver range

Where a ray might travel into ‘negative’ ranges, the simulation_range and simulation_cross_range define both positive and negative greatest extent. For instance, if a receiver is located 1 km away, and the scaling factor is 1.1, rays will travel up to 1.1 km in the negative range direction before terminating in the boundary.

For complex bathymetry and altimetry profiles, it is certainly possible that an eigenray might travel significantly past a receiver and then bounce back. In these cases, simulation_range cannot be estimated in advance and the user should manually set it to a sufficiently (but not overly) large value.

    simulation_depth_scale: float
    simulation_range_scale: float
    simulation_cross_range_scale: float

These scaling factors default to 1.01 in the depth direction, 1.1 in the range direction and 2.0 in the cross range direction.

    simulation_cross_range_min: float

For “degenerate” cases with bearing angle approaching zero and maximum cross range approaching zero, beams may exit the simulation boundary due to numerical issues. The value calculated for the cross range extent may capped at a minimum. By default this is 10 m.