Each component model provides the Flux Coupler with a set of output fields.
Output fields from a model include *output states*
(which can be used by another component to do a flux calculation)
and *output fluxes* (fluxes that were computed within the model
and which need to be disseminated to other component models).

The Coupler provides each component model with input fields.
Input fields sent to a model include *input states*
(the state variables of other models, which are needed to do a flux calculation)
and *input fluxes* (to be used as forcing fields).

§**2.1** Atmosphere Model

§**2.2** Ice Model

§**2.3** Land Model

§**2.4** Ocean Model

- layer height (m)
- u: zonal velocity (m/s)
- v: meridional velocity (m/s)
- potential temperature (°Kelvin)
- specific humidity (kg/kg)
- pressure (Pa)
- temperature (Kelvin)

**fluxes** - longwave, downward (W/m²)
- precipitation: liquid, convective (kg/s/m²)
- precipitation: liquid, large-scale (kg/s/m²)
- precipitation: frozen, convective (kg/s/m²)
- precipitation: frozen, large-scale (kg/s/m²)
- net shortwave radiation (W/m²)
- shortwave radiation: downward, visible, direct (W/m²)
- shortwave radiation: downward, near-infrared, direct (W/m²)
- shortwave radiation: downward, visible, diffuse (W/m²)
- shortwave radiation: downward, near-infrared, diffuse (W/m²)

** Data received from Coupler **

- albedo: visible, direct
- albedo: near-infrared, direct
- albedo: visible, diffuse
- albedo: near-infrared, diffuse
- surface temperature (° Kelvin)
- snow height (m)
- ice fraction
- ocean fraction
- land fraction

**fluxes** - zonal surface stress (N/m²)
- meridional surface stress (N/m²)
- latent heat (W/m²)
- sensible heat (W/m²)
- upward longwave heat (W/m²)
- evaporation (kg/s/m²)

**diagnostic quantities** - 2 meter reference air temperature (° Kelvin)

- ice fraction ( [0,1] )
- surface temperature (°Kelvin)
- u: zonal velocity (m/s)
- v: meridional velocity (m/s)
- snow depth (m)
- albedo: visible, direct, daily average
- albedo: near-infrared, direct, daily average
- albedo: visible, diffuse, daily average
- albedo: near-infrared, diffuse, daily average

**fluxes** - penetrating shortwave radiation (W/m²)
- ocean heat used for melting (W/m²)
- melt water (kg/s/m²)

** Data received from Coupler **

- dh/dx: zonal surface slope (m/m)
- dh/dy: meridional surface slope (m/m)

**fluxes** - zonal surface stress (N/m²)
- meridional surface stress (N/m²)
- net shortwave radiation (W/m²)
- latent+sensible+longwavedown+melting heat (W/m²)
- d(latent+sensible+longwavedown+melting heat)/dT (W/m²/°K)
- upward longwave radiation (W/m²)
- precipitation+evaporation (kg/s/m²)
- Q: heat of fusion (Q>0) or melting potential (Q<0) (W/m²)
- ice formed in ocean (kg/s/m²), derived in ice model from Q>0
- net atm/ocn heat flux (W/m²)

- surface temperature (Kelvin)
- albedo: visible, direct
- albedo: near-infrared, direct
- albedo: visible, diffuse
- albedo: near-infrared, diffuse
- snow height (m)

**fluxes** - zonal surface stress (N/m²)
- meridional surface stress (N/m²)
- latent heat (W/m²)
- sensible heat (W/m²)
- upward longwave heat (W/m²)
- evaporation (kg/s/m²)
- basin runoff (kg/s/basin)

**diagnostic quantities** - 2 meter reference air temperature (Kelvin)

** Data received from Coupler **

- atm layer height (m)
- atm u: zonal velocity (m/s)
- atm v: meridional velocity (m/s)
- atm potential temperature (°Kelvin)
- atm specific humidity (kg/kg)
- atm pressure (Pa)
- atm temperature (Kelvin)

**fluxes** - longwave, downward (W/m²)
- precipitation: liquid, convective (kg/s/m²)
- precipitation: liquid, large-scale (kg/s/m²)
- precipitation: frozen, convective (kg/s/m²)
- precipitation: frozen, large-scale (kg/s/m²)
- shortwave radiation: downward, visible, direct (W/m²)
- shortwave radiation: downward, near-infrared, direct (W/m²)
- shortwave radiation: downward, visible, diffuse (W/m²)
- shortwave radiation: downward, near-infrared, diffuse (W/m²)

- SST: surface temperature (°Kelvin)
- u: zonal velocity (m/s)
- v: meridional velocity (m/s)
- dh/dx: zonal surface slope (m/m)
- dh/dy: meridional surface slope (m/m)

**fluxes** - Q: heat of fusion (Q>0) or melting potential (Q<0) (W/m²)

** Data received From Coupler **

- zonal surface stress (N/m²)
- meridional surface stress (N/m²)
- net shortwave radiation (W/m²)
- latent+sensible+longwave+melting heat (W/m²)
- precipitation+evaporation+melting water (kg/s/m²)
- land runoff water (kg/s/basin)