MEGAN Emissions

prepmegan4cmaq is a fortran program that grids all the data needed to run biogenic emissions inside CMAQ model.

Dependencies:

• Fortran GNU compiler
• NetCDF library

Get MEGAN input data:

All the data required to run this pre-processor is freely available from MEGAN GLOBAL DATA.

Data required:

• Leaf Area Index / Vegetation Cover Fraction (LAIv).
• Growth type (fraction): crop, grass, shurb, tree, tropical trees, needleleaf trees..
• Ecotype.
• Soil data (for BDSNP soil NO algorithm): Land type, Climate data (arid/non-arid), Nitrogen deposition and soil Nitrogen from fertilizers.

Build

Go to the src directory:

> cd src/

Edit the Makefile to set the compiler and path to NetCDF lib and include files. Check your nc-config --libdir and nc-config --includedir.

> make

If the compilation is successful, the executable prepmegan4cmaq.exe should be created.

Run

Edit the namelist example.inp that contains the following variables:

&control
griddesc_file='./GRIDDESC'
     gridname='LCC_TAN_TEST',

ecotypes_file='veg_Ecotypes.nc',
growtype_file='veg_GrowthFormFracions.nc',
    laiv_file='veg_LAIv.nc',
 climate_file='soil_climate.nc',
   ferti_file='soil_fert.nc',
landtype_file='soil_landtype.nc',
   nitro_file='soil_nitro.nc',

GtEcoEF_file="./db/GtEFbyEcotype.csv"      !Emission factor of each GT grouped by Ecotype
/

Note that the variables must be adjusted to match the appropriate values for your system.

Then execute prepmegan4cmaq.exe:

> ./prepmegan4cmaq.exe < example.inp

Please feel free to contact the developer if you have any issues or suggestions.

Planned future improvements:

• Reduce number input files and output files.
  • Group LAI files into one.
  • Group GT frac files into one.
  • Group Fert files and Nitro files.
  • Group landtype files by using int as id.
• Input and output files and variables with minningfull names.
• Remove GDAL/OGR dependence
  • Roboust GRIDDESC reader.
  • coordinate transformations functions
  • interpolation subroutines (bilinear, bicubic, average, mode, median)
• BDNP: Fert variable support.
• Add variables in the namelist to decide which sectons should be run.
• Add output format for CAMx and MEGAN (standalone)
• Add support for 8-day LAIv
• Create 8-day LAIv global data set
• Add an overall error checker at the end of the run.
• Check polar stereographic transformations (not yet validated)
• Add some scripts to download and prepare some input files (LAI, Fert, Nitro, etc.)