6.13. jules_deposition.nml

This file contains options and parameters for modelling of dry deposition of atmospheric trace constituents. It contains a variable number of namelists depending on the required model configuration. The namelist JULES_DEPOSITION is always required, and one or more instances of the namelist JULES_DEPOSITION_SPECIES is required if dry deposition has been selected.

Warning

Atmospheric deposition in JULES is still in development and is far from fully functional in this version - the code is included to allow further development. Users should not try to activate the deposition code: leave l_deposition as FALSE.

6.13.1. JULES_DEPOSITION namelist members

JULES_DEPOSITION::l_deposition
Type:

logical

Default:

FALSE

Switch to activate deposition code in JULES.

TRUE

Model deposition in JULES.

FALSE

Do not model deposition in JULES.

Only used if l_deposition = TRUE.

JULES_DEPOSITION::dry_dep_model
Type:

integer

Permitted:

1

Default:

none

Choice for model of dry deposition.

Possible values are:

  1. Parameterisation based on that found in UKCA (but now implemented in JULES).
JULES_DEPOSITION::l_deposition_flux
Type:

logical

Default:

FALSE

Switch for calculation of deposition fluxes as opposed to deposition velocities.

TRUE

Calculate deposition fluxes. This requires that the concentrations of atmopsheric tracer species are provided as prescribed data (see List of supported variables).

FALSE

Calculate deposition velocities.

Only used if l_deposition = TRUE and dry_dep_model = 1 (UKCA).

JULES_DEPOSITION::ndry_dep_species
Type:

integer

Permitted:

>= 1

Default:

none

Number of species for which dry deposition is calculated.

JULES_DEPOSITION::l_ukca_ddep_lev1
Type:

logical

Default:

FALSE

Switch controlling which atmospheric levels are used for dry deposition.

TRUE

Deposition occurs only from the lowest atmospheric level.

FALSE

Deposition occurs from all levels within the atmospheric boundary layer.

JULES_DEPOSITION::tundra_s_limit
Type:

real

Default:

none

Latitude of southern limit of tundra (degrees). This is used to alter the calculation of deposition of certain species in the tundra region (actually for all points north of this limit). Only used if the list of species (see dep_species_name_io) includes one or more of ‘CO’, ‘NO2’, ‘O3’, ‘PAN’, ‘PPAN’, ‘MPAN’ or ‘ONITU’.

JULES_DEPOSITION::dzl_const
Type:

real

Default:

none

Constant value for separation of boundary layer levels (m). All layer thicknesses are set to this value. This is used as a simple way to prescribe the layer thicknesses in standalone mode. This value can be overriden by prescribed data - see JULES_PRESCRIBED. This can be considered as the representative depth for tracer concentration and the depth over which the deposition flux is removed.

6.13.2. Notes on the JULES_DEPOSITION namelist

The height of the atmospheric boundary layer is required and is set to a default constant value of 1000 m. This value can be overridden via the namelist variable bl_height, or can be prescribed (i.e. allowed to vary in time and/or space) by providing bl_height as prescribed data (see List of supported variables).

The number of model levels in the boundary layer is required and is set to a default balues of 1. This can be overridden via the namelist variable bl_levels. The number of levels is only used to communicate with the atmospheric model (e.g. UKCA).

The separation of the model levels in the boundary layer is required and is set to a constant value via dzl_const. The separation can be prescribed (i.e. allowed to vary in time and/or space) by providing level_separation as prescribed data (see List of supported variables). This can be considered as the representative depth for tracer concentration and the depth over which the deposition flux is removed.

If deposition fluxes (rather than deposition velocities) are to be calculated (see l_deposition_flux), the concentrations of atmospheric tracer species need to be prescribed (see tracer_field in List of supported variables).

6.13.3. JULES_DEPOSITION_SPECIES namelist members

This namelist should occur ndry_dep_species times, with each occurence containing parameters for an atmospheric tracer species that is to be considered in dry deposition.

JULES_DEPOSITION_SPECIES::dep_species_name_io
Type:

character

Default:

none

Name of an atmospheric tracer species to be included in deposition modelling.

JULES_DEPOSITION_SPECIES::diffusion_coeff_io
Type:

real

Default:

none

Diffusion coefficient (m-2 s-1).

JULES_DEPOSITION_SPECIES::rsurf_std_io
Type:

real(ntype)

Default:

none

Standard value of surface resistance for each surface type (s m-1).

Only used if dep_species_name_io = NO2, O3, PAN, PPAN, MPAN or ONITU. Values provided for other species will be ignored.

JULES_DEPOSITION_SPECIES::diffusion_corr_io
Type:

real

Default:

none

Diffusion correction factor for stomatal resistance, accounting for the different diffusivities of water and other species (dimensionless).

Only used if dep_species_name_io = CO, NO2, O3, PAN, PPAN, MPAN or ONITU. Values provided for other species will be ignored.

JULES_DEPOSITION_SPECIES::r_tundra_io
Type:

real

Default:

none

Surface resistance used in tundra region (s m-1).

Only used if dep_species_name_io = CH4.

JULES_DEPOSITION_SPECIES::ch4_scaling_io
Type:

real

Default:

none

Scaling applied to methane soil uptake (dimensionless). (Originally this was used to match the value from the IPCC Third Assessment Report.)

JULES_DEPOSITION_SPECIES::ch4dd_tundra_io
Type:

real(4)

Default:

none

Coefficients of cubic polynomial relating methane loss for tundra to temperature. Flux is in units of ug (CH4) m-2 s-1.

Only used if dep_species_name_io = H2.

JULES_DEPOSITION_SPECIES::h2dd_c_io
Type:

real(ntype)

Default:

none

Constant in quadratic function relating hydrogen deposition to soil moisture (s m-1).

JULES_DEPOSITION_SPECIES::h2dd_m_io
Type:

real(ntype)

Default:

none

Coefficient of first order term in quadratic function relating hydrogen deposition to soil moisture (s m-1).

JULES_DEPOSITION_SPECIES::h2dd_q_io
Type:

real(ntype)

Default:

none

Coefficient of second order term in quadratic function relating hydrogen deposition to soil moisture (s m-1).

Only used if dep_species_name_io = HNO3, HONO2 or ISON.

JULES_DEPOSITION_SPECIES::dd_ice_coeff
Type:

real(3)

Default:

none

Coefficients in quadratic function relating dry deposition over ice to temperature.

Only used if dep_species_name_io = O3.

JULES_DEPOSITION_SPECIES::cuticle_o3_io
Type:

real

Default:

none

Constant for calculation of cuticular resistance for ozone (s m-1).

JULES_DEPOSITION_SPECIES::r_wet_soil_o3_io
Type:

real

Default:

none

Wet soil surface resistance for ozone (s m-1).