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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

  1. Determine plume vertical extent: bottom = max(elevation, surface_altitude), top = max(cloud_top, surface_altitude).
  2. For eruptive profile, concentrate emissions in the upper 1/3 of the plume: z_bot_volc = z_top − (z_top − z_bot) / 3.
  3. For each vertical level, compute the fractional overlap between the model layer and the plume injection zone.
  4. Distribute sulfur_emission * fraction into each overlapping level.
  5. 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