Volcano¶

Overview¶

Computes volcanic sulfur dioxide (SO₂) emissions as a point source with vertical distribution based on eruption plume height. The scheme injects SO₂ into the atmospheric column at a specified grid location, distributing emissions vertically between the volcanic vent elevation and cloud top height, concentrated in the upper third of the plume (eruptive profile).

Registration Names¶

Native C++: "volcano"
Fortran bridge: "volcano_fortran"

Configuration Parameters¶

YAML Key	Type	Default	Description
`target_i`	int	1	Grid i-index for volcanic source location
`target_j`	int	1	Grid j-index for volcanic source location
`sulfur_emission`	double	1.0	SO₂ emission rate [kg/s]
`elevation`	double	600.0	Volcanic vent elevation [m]
`cloud_top`	double	2000.0	Cloud top / plume top height [m]

Import Fields¶

Field Name	Units	Description
`surface_altitude`	m	Surface elevation
`layer_thickness`	m	Thickness of each vertical layer

Export Fields¶

Field Name	Units	Description
`volcanic_so2`	kg/s	Volcanic SO₂ emission rate (3D)

Algorithm¶

Determine plume vertical extent: bottom = max(elevation, surface_altitude), top = max(cloud_top, surface_altitude).
For eruptive profile, concentrate emissions in the upper ⅓ of the plume: z_bot_volc = z_top − (z_top − z_bot) / 3.
For each vertical level, compute the fractional overlap between the model layer and the plume injection zone.
Distribute sulfur_emission * fraction into each overlapping level.
If plume height is zero or negative, all emissions go into the surface level.

YAML Configuration Example¶

physics:
  - name: volcano
    config:
      target_i: 50
      target_j: 30
      sulfur_emission: 1000.0
      elevation: 1500.0
      cloud_top: 8000.0

Implementation Notes¶

Available as both native C++ (Kokkos) and Fortran bridge implementations
The scheme is a point source — it only modifies a single (i, j) column
The Kokkos kernel iterates over vertical levels only (not the full 3D grid)
In a real coupled model, target_i/target_j would need to be mapped to local process bounds