Simplified Chemistry: Difference between revisions

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* partly information about included emission data (ANT=anthropogenic emission, BIO=biogenic emission, BBE=biomass burning emission, more information about available emission data, see [[Emission Data]])
* partly information about included emission data (ANT=anthropogenic emission, BIO=biogenic emission, BBE=biomass burning emission, more information about available emission data, see [[Emission Data]])
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Part 4: Chemtracer-xml-file for OH chemistry (Example configuration)
Chemtracer-xml-file for OH chemistry (Example configuration)
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Revision as of 14:47, 20 July 2023

- work in progress -

In this first example it is shown how to perform a simulation of with simplified chemistry in ICON-ART. This tutorial teaches you...

  • the basics of setting up an ICON runscript with ICON-ART settings
  • the use of the most simple ICON-ART namelist parameter
  • the implementation of the desired chemical species in a simulation by setting up a chemtracer xml-data for simplified chemistry simulations
  • the implementation of emission data in a simulation

Emission data will be applied on the simulation as well.

Configuration case

The depicted case is about simulating the tropospheric hydroxyl radical (OH), one of the most important oxidants of the atmosphere. It's main source in the lower troposphere is the photolysis of ozone and its consequent reaction of an excited oxygen atom with the surrounding water vapor:

Additionally the excited Oxygen atom reacts further with Nitrogen and Oxygen:

The main sink of OH in the Troposphere is methane and carbon monooxide:

Now the OH concentrations are calculated with the respective kinetic and photolysis constants, based on chemical kinetic laws: Failed to parse (syntax error): {\displaystyle [\ce{OH}]=\frac{\mathrm{2[\ce{O(^1D)}]}k_{\ce{H2O}}[\ce{H2O}]}{k_{\ce{CH4}}[\ce{CH4}]+(k_{\ce{CO,1}}+k_{\ce{CO,2}})[\ce{CO}]}} with Failed to parse (syntax error): {\displaystyle [\ce{O(^1D)}]=\frac{J_{\ce{O3}}[\ce{O3}]}{k_{\ce{O2}}[\ce{O2}]+k_{\ce{N2}}[\ce{N2}]+k_{\ce{H2O}}[\ce{H2O}]}} .

Additionally emission data of the main sinks of OH are implemented. Since the simulation is performed on a R2B05-grid the following emission data are the most suitable ones for the respective trace gases:

  • : anthropogenic (EDGAR-432 monthly), biomass-burning (GFED3), biogenic (MEGAN-MACC)
  • : anthropogenic (EDGAR-432 monthly)

For more information on recommended emission data see the abstract, dealing with Emission Data. Since emission data are relatively large, they can also just be left out.

Setting up the Runscript

Let's start with the runscript that has to be prepared. Please note that the in the following explained parts have to be printed in one runscript-file with the naming designation "xyz.run". Here it is named ohsim_simple_icon.run but of course you can call it differently as well.

Inside of that, first check that all your directories are correct, probably they have to be adjusted. Abbreviations used here are the following:

  • CENTER: Your organization
  • EXPNAME: name of your ICON-Simulation
  • OUTDIR: Directory where the simulation output will be stored
  • ARTFOLDER: Directory where the ICON-ART code is stored
  • INDIR: Directory where the necessary Input data are stored
  • EXP:
  • lart: For ICON-ART Simulation that has to be switched to Oheim_simple_icon.run.

Part 1: Runscript Directory Settings (Example configuration)

Additionally in the next lines of code you set the timing. In this simulation we only simulate a few days. Because OH is dependent from the solar radiation, the output interval is set to 10 hours to calculate OH to every time of the day.

Part 2: Runscript Timing Settings (Example configuration)

Further, all the namelist parameters (from the regular ICON model without ART-extension) have to be set. For a regular ICON-ART-Simulation the following settings are recommended - if not stated differently.

Part 3: Runscript ICON-Parameter and -Namelist Settings (Example configuration)

Please note in the last namelist section "output_nml" that you can set all output variables that you need to postprocess your data later. All assigned variables here will be written in the output netCDF-files as well. To learn more about post processing your data, check out a later chapter of this article or the Postprocessing article.

Now, we're getting to the ICON-ART settings. To enable chemistry in an ICON-ART Simulation inn general, the switch lart_chem has to be set to .TRUE.. With lart_diag_out output of the diagnostic fields can be enabled. Due to setting lart_chem=.TRUE. either lart_chemtracer or lart_mecca have to be set to .TRUE.. Because we want to perform a simulation with simplified chemistry, we have to switch on lart_chemtracer. If this namelist parameter is set to .TRUE., also cart_chemtracer_xml has to be fulfilled. Here you enter the path of your xml-file which describes the tracers occurring and their properties in the simulation. How to create this xml-file is explained in the next chapter. Because this xml-file will contain information about included emission data of certain chemical species, in cart_emiss_xml_file the path of a second emission-xml-file has to be set. An example configuration for this part is shown in the following:

Part 4: Runscript ICON-ART Settings (Example configuration)

Please note that there are also several other namelist parameter you can select from (see Namelist article) but to perform our we're done for this part.

Depending on the used HPC-System, some parameter concerning the running job like maximum running time and used nodes can be set. For this case study the following settings can be copied. Note that this is valid for the HoreKa HPC system and that it can differ to other systems.

Part 5: Runscript job Settings (Example configuration)

To conclude and to double check, in the following box the complete runscript is shown once again.

Complete example configuration of the runscript

Setting up the xml-files

An xml-file describes the chemical components of the simulation which means that all trace gases or aerosols and their properties that are relevant for the simulation are listed here. Since we perform a simulation with simplified ICON-ART chemistry we need the matching chemtracer-xml-file. Additionally we need to create an emission-xml-file since emission data of certain chemical species is included in our simulation.

Chemtracer-xml-file

This file contains all the necessary information to describe the chemical mechanism with the respective important chemical species. The following information are given per chemical species:

  • properties like mol weight, units or lifetime of the tracer
  • main sink
  • main reaction product after reacting with the main sink after a given lifetime
  • partly information about included emission data (ANT=anthropogenic emission, BIO=biogenic emission, BBE=biomass burning emission, more information about available emission data, see Emission Data)

Chemtracer-xml-file for OH chemistry (Example configuration)

Emission-xml-file

To link the information from the chemtracer-xml-file that we want to include emission data of a specific chemical species with the specific information about the respective emission, ICON-ART is working with, we need a second xml-file: The emission-xml-file. It is normally a standard grid-dependant xml-file you can use where nothing has to be changed. Since this Simulation is performed on a R2B05 grid, we use the emissions_R2B05_0014_cs.xml. Have a look at the article about Emission Data to check out all the available emission-xml-files for different resolutions.

Running the simulation

Double check all filled in paths and namelist - especially the ART-namelists. If every namelist parameter in the runscript is filled in correctly, the runscript has to be saved. Afterwards by typing

/.ohsim_simple_icon.run

a job can be submitted to the respective HPC-System. Type the terminal command

squeue

to view a list of your submitted and currently running and jobs. By changing in the output directory (which is according to our runscript /hkfs/work/workspace/scratch/hp8526-ws_icon_oh/output/ohsim_icon_simple_atom1 you can check the slurm file for possible errors and run times after your job has been run through.

In the output directory you can also find all output data for postprocessing in netCDF format.