Salt Budgets

This page outlines the pertinent files and methodology to compute a salt budget using output from an MITgcm model.

Required Fields

The following fields are required for the salt budget:

Field	Variable Name	Units
Zonal Advective Flux of Salinity	ADVx_SLT	g/kg m\(^3\)/s
Meridional Advective Flux of Salinity	ADVy_SLT	g/kg m\(^3\)/s
Vertical Advective Flux of Salinity	ADVr_SLT	g/kg m\(^3\)/s
Zonal Diffusive Flux of Salinity	DFxE_SLT	g/kg m\(^3\)/s
Meridional Diffusive Flux of Salinity	DFyE_SLT	g/kg m\(^3\)/s
Vertical Diffusive Flux of Salinity (Explicit part)	DFrE_SLT	g/kg m\(^3\)/s
Vertical Diffusive Flux of Salinity (Implicit part)	DFrI_SLT	g/kg m\(^3\)/s
Net surface freshwater flux	oceFWflx	kg/m\(^2\)/s
Vertical mass-weighted transport of Potential Temperature	WSLTMASS	g/kg m\(^3\)/s
Total surface salt flux	SFLUX	g/m\(^2\)/s
Vertical Diffusive Flux (KPP Scheme)	KPPg_SLT	g/kg m\(^3\)/s

Note that the KPPg_SLT variable is only required when using the kpp package.

Note

If implicitDiffusion=.TRUE., then the diffusive flux terms DFxE_SLT, DFyE_SLT, and DFrE_SLT are not required to close the budget.

Suggested Diagnostics Organization

The following entries to the data.diagnostics file would yield the terms above.

#---
frequency(1)  = 86400.0,
fields(1:3,1) = 'ADVx_SLT','ADVy_SLT','ADVr_SLT',
filename(1)   = 'diags/salt_flux_adv/salt_flux_adv',

#---
frequency(2)  = 86400.0,
fields(1:5,2) = 'DFxE_SLT','DFyE_SLT','DFrE_SLT','DFrI_SLT','KPPg_SLT',
filename(2)   = 'diags/salt_flux_diff/salt_flux_diff',

#---
frequency(3)  = 86400.0,
fields(1:3,3) = 'oceFWflx','WSLTMASS','SFLUX   ',
filename(3)   = 'diags/salt_flux_surf/salt_flux_surf',
levels(:,3)     = 1