Namelist

Recommended ICON Namelist Settings

It is necessary for the user to choose the ICON settings carefully. Part of the values listed in are recommended to obtain a stable ICON-ART simulation with scientifically reasonable results. Another part is necessary to enable ART features like aerosol-cloud-interactions.

Recommended ICON namelist settings for ART tracers.

Parameter	Value	Namelist	Description
dtime	-	run_nml	If facing stability problems, it is recommended to use a shorter time step as recommended by operational setups (e.g. ${\textstyle {\frac {3}{5}}\cdot }$dtime${\textstyle _{oper}}$).
ndyn_substeps	-	run_nml	There is no need to call the dynamics more often than in operational setup. Adjust it according to your dtime choice.
inwp_gscp	6	nwp_phy_nml	In order to enable aerosol-cloud-interactions within ICON-ART, you have to specify this. Note, that you will still need to set iart_aci_warm and iart_aci_cold from .
irad_aero	6	radiation_nml	aerosol optical properties are taken from climatology
	9		optical properties depend on aerosol concentrations (set iart_ari = 1 in art_nml )

ART Namelists

ICON-ART has an own namelist to modify the setup of ART simulations at runtime. The main switch for ART, lart, is located inside run_nml. The namelist for the other ART switches is called art_nml.

A naming convention is used in order to show the type of data. An INTEGER namelist parameter starts with iart_, a REAL namelist parameter starts with rart_, a LOGICAL namelist parameter starts with lart_, and a CHARACTER namelist parameter starts with cart_.

The ICON-ART namelist is located in the module src/namelists/mo_art_nml.f90. General namelist parameters are listed and explained within . Namelist parameters for ART input are listed within . Namelist parameters related to atmospheric chemistry are listed within . Namelist parameters related to aerosol physics are listed within . Namelist parameters related to feedback processes between aerosols and meteorological variables are listed in . Finally, namelist parameters related to physics parameterizations in ICON are listed in .

Art namelist parameters

Name	function
General Variables
cart_input_folder	Absolute Path to ART source code
iart_init_aero	Initialization of aerosol species
iart_init_gas	Initialization of gaseous species
lart_diag_out	Enable output of diagnostic fields
lart_pntSrc	Enables point sources
lart_emiss_turbdiff	Switch if emissions should be included as surface flux condition
cart_io_suffix	user given suffix instead of automatically generated grid number
Atmospheric Chemistry
lart_chem	Main switch to enable chemistry
lart_chemtracer	Switch for parametrised chemtracers
lart_mecca	Switch for MECCA chemistry
lart_psc	Switch for computation of PSCs
cart_vortex_init_date	Date of vortex initialization
cheminit_file(max_dom)	Path to chemical initialization file
cart_cheminit_coord	Path to chemical initialization coordinate file
cart_cheminit_type	Type of chemical initialization coordinate file
XML configuration
cart_chemtracer_xml	Path to XML file for parametrised chemtracers
cart_mecca_xml	Path to XML file for MECCA tracers
cart_aerosol_xml	Path to XML file for aerosol tracers
cart_modes_xml	Path to XML file for modes
cart_pntSrc_xml	Path to XML file for point sources
cart_diagnostics_xml	Path to XML file for aerosol diagnostics
cart_emiss_xml_file	Path and file name of the xml files for emission metadata
cart_ext_data_xml	Path to XML file for metadata of datasets prescribing tracers
Atmospheric Aerosol
lart_aerosol	Main switch for the treatment of atmospheric aerosol
iart_seasalt	Treatment of sea salt aerosol
iart_dust	Treatment of mineral dust aerosol
iart_anthro	Treatment of anthropogenic aerosol
iart_fire	Treatment of wildfire aerosol
iart_volcano	Treatment of volcanic ash aerosol
iart_nonsph	Treatment of nonspherical particles
iart_pollen	Treatment of pollen
iart_radioact	Treatment of radioactive particles
cart_volcano_file	Absolute path + filename of input file for volcanoes
cart_radioact_file	Absolute path + filename of input for radioactive emissions
Feedback Processes
iart_aci_warm	Nucleation of aerosol to cloud droplets
iart_aci_cold	Nucleation of aerosol to cloud ice
iart_ari	Direct interaction of aerosol with radiation

General art_nml namelist switches and respective parameters.

Namelist parameter	Default	Description	If .TRUE. then needs
iart_modeshift	1

General namelist parameters to control the ART routines. For naming conventions, see . These switches are - with the exception of lart- located inside art_nml.

		Description
lart	.FALSE.	Main switch which enables the ART modules. Located in the namelist run_nml .
iart_init_aero		Initialization of aerosol species. Possible values: : Initialization with 0. : Initialization with Climatology1 (not yet implemented) : Initialization from files (see )
iart_init_gas		Initialization of gaseous species. Possible values: : Initialization with 0. : Initialization with Climatology1 (not yet implemented) : Initialization in modus, given by the .xml file input declaration init_mode(see ) : Initialization from files (see )
lart_chem	.FALSE.	Enables chemistry. The chemical mechanism and the according species are set via lart_chemtracer and lart_mecca.
lart_pntSrc	.FALSE.	Enables addition of point sources for passive tracer. The sources are controled via cart_pntSrc_xml.
lart_aerosol	.FALSE.	Main switch for the treatment of atmospheric aerosol.
lart_diag_out	.FALSE.	If this switch is set to .TRUE., diagnostic output fields are available. Set it to .FALSE. when facing memory problems.

Namelist parameters to control ART input. These switches are located inside art_nml.

cart_io_suffix(ndom)	’grid-number’	Specifies the grid specification in ART input file name convention (see section [sec:name_concept]). With default grid-number it is replaced by the four character string due to ICON parameter number_of_grid_used . Any other string can be included for each domain.
cart_input_folder	”	Absolute path where input files, like initialization files are located.
cart_emiss_xml_file	”	Path and file name to the XML file for specifying emission metadata.
cart_chemtracer_xml	”	Path and file name to the XML file for specifying chemical and passive tracer.
cart_mecca_xml	”	Path and file name to the XML file for specifying tracers of the MECCA chemical mechanism.
cart_aerosol_xml	”	Path and file name to the XML file for specifying aerosol tracer.
cart_modes_xml	”	Path and file name to the XML file for specifying aerosol modes.
cart_pntSrc_xml	”	Path and file name to the XML file for specifying point source emissions.
cart_diagnostics_xml	”	Path and file name to the XML file for specifying (mainly GRIB2) metadata for diagnostic output variables. Not needed for NetCDF output at the moment.
cart_ext_data_xml	”	Path and file name to the XML file for specifying metadata of external datasets for prescribing tracers.

Namelist parameters related to atmospheric chemistry. For naming conventions, see . These switches art located inside art_nml.

		Description
lart_chemtracer	.FALSE.	Enables the computation of simplified chemistry and passive tracers.
lart_mecca	.FALSE.	Enables the computation of full chemistry via the MECCA package.
cart_vortex_init_date	’ ’	Date of vortex initialization
cart_cheminit_file	’ ’	Path to chemical initialization file
cart_cheminit_coord	’ ’	Path to chemical initialization coordinate file
cart_cheminit_type	’ ’	Type of chemical initialization coordinate file
lart_psc	.FALSE.	Switch if polar stratospheric clouds should be calculated

Namelist parameters related to aerosol physics. For naming conventions, see . These switches are located in art_nml .

		Description
iart_seasalt		Treatment of sea salt aerosol. Possible values: : No treatment. : As specified in . Add 6 to iart_ntracer .
iart_dust		Treatment of mineral dust aerosol. Possible values: : No treatment. : As specified in . : Simplified version of .
iart_volcano		Treatment of volcanic ash particles. Possible values: : No treatment. : 1-moment treatment. As described in . Add 6 to iart_ntracer . : 2-moment treatment. Add 6 to iart_ntracer .
cart_volcano_file	”	Path and filename of the input file for the geographical position and the type of volcanoes.
iart_radioact		Treatment of radioactive nuclei. Possible values: : No treatment. : As described in the ICON-ART technical documentation. An input file has to be specified via cart_radioact_file. Add 9 to iart_ntracer .
cart_radioact_file	”	Path and filename of the input file for the dispersion of radioactive nuclei.
iart_pollen		Treatment of pollen. Possible values: : No treatment. :

Namelist parameters related to feedback processes between aerosols and meteorological variables. For naming conventions, see .

		Description
iart_aci_warm		Treatment of warm-phase activation. Note, that inwp_gscp = 6 is a prerequisite for aerosol-cloud-interactions. Possible values: : Constant ${\textstyle qni=200\,\mathrm {cm} ^{-3}}$ as for inwp_gscp = 4. : with extensions .
iart_aci_cold		Treatment of cold-phase nucleation. Note, that inwp_gscp = 6 is a prerequisite for aerosol-cloud-interactions. Possible values: : scheme with constant IN properties as for inwp_gscp = 4. : scheme with scheme for het. nucleation. : scheme with scheme for het. nucleation. : scheme with scheme for het. nucleation. : scheme with scheme for het. nucleation. : scheme with Ullrich et al. scheme for het. nucleation. : scheme with scheme for het. nucleation and budget variable for activated dust IN. : scheme with prognostic mineral dust IN and budget variable for activated dust IN.
iart_ari		Direct interaction of simulated aerosol with radiation (here default: irad_aero = 6 ).: no interaction : with interaction. Set irad_aero = 9 in radiation_nml

		Description
lart_conv	.TRUE.	Consider tendencies due to the convection parameterization.
lart_turb	.TRUE.	Consider tendencies due to the turbulent diffusion parameterization.

General art_nml namelist switches and respective parameters.

Namelist parameter	Default	Description	If .TRUE. then needs
lart_chem	.FALSE.	Enables chemistry.	lart_chemtracer = .TRUE.OR lart_mecca = .TRUE.
lart_chemtracer	.FALSE.	Switch for simple OH chemistry	cart_chemtracer_xml
lart_mecca	.FALSE.	Switch for kpp chemistry	cart_mecca_xml
lart_pntSrc	.FALSE.	Enables addition of point sources	cart_pntSrc_xml
lart_aerosol	.FALSE.	Main switch for the treatment of	cart_aerosol_xml
		atmospheric aerosol.	and cart_modes_xml
lart_diag_out	.FALSE.	Enables diagnostic output fields	cart_diagnostics_xml