Input

Input

Requirements for a Simulation

To run a Simulation with ICON-ART there are three main points to consider: Setting the namelist parameters, preparing the xmls, and optionally prepare additional Input data.

Namelist Inputs

To run a simulation with ICON-ART installed the first thing to prepare is the runfile. It is usually best to start with an existing and working runfile and adapt parts as needed. The runfile contains the majority of parameters to run a simulation, like the length, timesteps and grids used, as well as a variety of options for methods and parametrisations used in the model. The runfile contents are then split up in several namelists that the model reads at the beginning of a simulation. An overview of the Namelist Parameters can be found in Namelist.

To enable ART in an ICON simulation, the switch lart = .TRUE. has to be set in the section &run_nml. This is the global on/off switch for ICON-ART. This is how this could look like in the context of a runfile:

! run_nml: general switches ----------
&run_nml
 ltestcase = .FALSE.
 num_lev = 50
 ltransport = .TRUE.
.............

 \textcolor{red}{lart = .TRUE.}

Generally the first letters of a namelist switch refer to its type, the "l" in "lart" stands for logical, meaning it has to be either True or False. Here are some examples.

Some namelist switches and their data types.

namelist switch	type
lart	logical
cart_aerosol_xml	character
iart_init_aero	integer

The namelist &art_nml is used for general options of the ART simulation. To run a certain kind of simulation the according switch has to be set to .TRUE.. For Example to include a point source the switch cart_aerosol_xml has to be set to .TRUE..

XML Inputs

This enables the inclusion of a .xml file containing additional information like location and strength of the point source. The table below contains the most important &art_nml namelist parameters and additional namelist parameters required if they are set to .TRUE..

XML files and their namelist dependencies

XML File	Description	Namelist parameter dependency	Default
cart_chemtracer_xml	Switch for simple OH chemistry	lart_chemtracer	.FALSE.
cart_mecca_xml	Switch for kpp chemistry	lart_mecca	.FALSE.
cart_pntSrc_xml	Enables addition of point sources	lart_pntSrc	.FALSE.
cart_aerosol_xml	Main switch for the treatment of atmospheric aerosols	lart_aerosol	.FALSE.
cart_modes_xml	Main switch for the treatment of atmospheric aerosols	lart_aerosol	.FALSE.
cart_diagnostics_xml	Enables diagnostic output fields	lart_diag_out	.FALSE.

The reason for the use of those additional .xml files is that the ART variables they contain (sea salt, mineral dust etc.) might be different for every run which differs from the Icon Variables (Temperature, Pressure, etc.) which usually don’t change between runs. .xml files are readable for both humans and machines, which makes them easy to tweak and integrate. An Example for the contents of an .xml file adding ash particles can be seen below.

<modes>
  <aerosol id="asha">
    <kind type="char">2mom</kind>
    <d_gn type="real">1.190E-6</d_gn>
    <sigma_g type="real">1.410E+0</sigma_g>
    <rho type="real">2.600E+3</rho>
  </aerosol>
</modes>

Further .xml examples can be fount in /your_ART_Directory/runctrl_examples/xml_ctrl.

Input Data

Depending on the type of simulation there might be additional input files required. These are essential files that are not contained in classical ICON initialisation data. For example for the emission of mineral dust there has to be information about the soil types supplied to the model. The additional input files should be renamed to a netcdf file and follow the naming convention shown in fig 1.1. Please note that the XXX has to be replaced by one of the indices mentionend in Table input-init and input-emissions.

Additional input files for the initialisation

Species	Namelist switch	Options	XXX
Gas	iart_init_gas	0 (cold start), 5 (from file)	IGX
Aerosol	iart_init_aero	0 (cold start), 5 (from file)	IAE

Additional input files for the emissions

Type	Data	XXX
Point souces	XML-file	-
Sea salt	no extra data necessary	-
Mineral Dust	Soil Type Data	ART_STY
Biogenic VOCs	Emissions or Vegetatiom	ART_STY
Athropogenic emissions	Emission data sets	ART_BIO ART_ANT
Biomass burning	Satellite data	ART_BCF

Obtaining Input Data

The 2 ways of obtaining input data are to generate it yourself or download it.

How to generate input data

How to download input data