Coupling MOZART-4 with Meso-NH for initial and boundary conditions

Create your own chemical scheme

The following procedure is valid for Meso-NH versions since MASDEV4_9_0

STEP 1: write your chemical scheme

in a specified format (*.chf) like this one: ReLACS-mix-reac.chf

Edit this chf file and make the necessary changes.

STEP 2: create the fortran source

with the awk program m10.awk

Usage: "m10.awk ReLACS-mix-reac.chf"

STEP 3: compile your chemical scheme

Change the name of the chemical scheme to BASIC.f90

Create your user library (see the A-INSTALL file) and compile.

Scripts to create emissions files in the right format for PREP PGD


The following scripts are designed to convert the original emission files taken from the GEIA/ECCAD international program ( to the latitude-longitude-value ascii format needed by the PREP_PGD .

Emissions files are downloaded from the ECCAD web site in the netcdf format.

The scripts emiss_conv_nc_to_asc.ncl converts netcdf format to lat-lon-val with final emissions in molec/cm2/s.

The script needs to be adapted to the user requirements:


When running the model, the routine build_emisstabn.F90 in SURFEX will automatically make the conversion of the above mentioned units to molec/m2/s according to the keyword provided in the chemistry file under the EMISUNIT keyword: MOL (if emissions are provided in microMol/m2/day), MIX (if emissions are provided in ppp m/s), CON (emissions are provided in molec/cm2/s).


emission fluxes in microMole/m2/day

emission fluxes in ppp m/s

emission fluxes in molec/cm2/s

Example of input file for chemistry: CCHEM INPUT FILE

To run the chemistry in Meso-NH, additional informations are needed such as Henry's law coefficients, molecular masses, etc. These informations need to be provided in an input file which name is specified in the namelist EXSEG1.nam:

 . &NAM_CH_MNHCn       LUSECHEM = T,
 .                     CCHEM_INPUT_FILE  = "MNHC.input",

An example of such a file is given here MNHC.input which is compatible with the default chemical scheme provided with the Meso-NH package.

This file allows the user to initialize the chemical species with fixed


Photolysis rates are computed based on the TUV program developped at NCAR (Source:

In order to run the TUV program (version 5.0) in Meso-NH, additional files are needed which can be downloaded here: tuv50.tar.gz

Mesonh-49: MesonhTEAMFAQ/Chemistry (last edited 2014-06-03 14:05:06 by JuanEscobar)