Sea Salt¶

Overview¶

Computes size-resolved sea salt aerosol emissions from ocean surfaces using the Gong (2003) source function. The scheme integrates the normalized particle source function over accumulation mode (SALA) and coarse mode (SALC) size ranges, then scales by wind speed and sea surface temperature (SST).

References: - Gong, S.L., et al. (2003), A parameterization of sea-salt aerosol source function for sub- and super-micron particles, Global Biogeochem. Cycles, 17(4).

Registration Names¶

Native C++: "sea_salt"
Fortran bridge: "sea_salt_fortran"

Configuration Parameters¶

YAML Key	Type	Default	Description
`integration_step`	double	0.05	Integration step size for Gong source function [μm]
`r80_dry_ratio`	double	2.0	Ratio of r80 (radius at 80% RH) to dry radius
`sea_salt_density`	double	2200.0	Sea salt particle density [kg/m³]
`r_sala_min`	double	0.01	Minimum dry radius for accumulation mode [μm]
`r_sala_max`	double	0.5	Maximum dry radius for accumulation mode [μm]
`r_salc_min`	double	0.5	Minimum dry radius for coarse mode [μm]
`r_salc_max`	double	8.0	Maximum dry radius for coarse mode [μm]
`sst_coeff`	sequence[4]	[0.329, 0.0904, -0.00717, 0.000207]	SST scaling polynomial coefficients
`u_power`	double	3.41	Wind speed power-law exponent

Import Fields¶

Field Name	Units	Description
`wind_speed`	m/s	10-meter wind speed
`tskin`	K	Sea surface skin temperature

Export Fields¶

Field Name	Units	Description
`secondary_input`	kg/m²/s	Accumulation mode (SALA) sea salt emissions
`coarse_input`	kg/m²/s	Coarse mode (SALC) sea salt emissions

Algorithm¶

During initialization, integrate the Gong (2003) normalized source function dF/dr80 over the SALA and SALC size ranges to compute reference mass emission rates (srrc_SALA_, srrc_SALC_).
At each grid cell, compute SST scaling using a cubic polynomial (Horner's method): scale = c0 + SST*(c1 + SST*(c2 + SST*c3)), with SST clamped to [0, 30] °C.
Compute wind factor as u^u_pow (default u^3.41).
Emission = scale * u_factor * reference_rate for each mode.

YAML Configuration Example¶

physics:
  - name: sea_salt
    config:
      r_sala_min: 0.01
      r_sala_max: 0.5
      r_salc_min: 0.5
      r_salc_max: 8.0
      u_power: 3.41
      sst_coeff: [0.329, 0.0904, -0.00717, 0.000207]

Implementation Notes¶

Available as both native C++ (Kokkos) and Fortran bridge implementations
SALA and SALC are computed in separate Kokkos kernels and independently MarkModified
The Gong source function integration is performed once during Initialize; only the wind/SST scaling runs per timestep