CMEM: Community Microwave Emission Modelling Platform

CMEM Download  

Platform source code (top)

CMEM (Copyright © ECMWF) is a Fortran90 software package. It has been tested with pgf90, gfortran and ifc fortran compilers. It includes 47 subroutines and 9880 lines.

Download CMEM:

When you download CMEM, please keep us informed, by sending us an e-mail (see contact). You will then be added to the CMEM users diffusion list and we will keep you informed of any modifications, bug reports and new version of the code.

Current version (10 May 2012):

Download CMEM version 4.1

Characteristics of this new tag and difference with previous version.

Bug report on cmem v4.0

Previous versions:

v4.0 (February 2012): Characteristics and Bug report ; download

v3.0 (November 2009): Characteristics and Bug report ; download

v2.1 (March 2009): Characteristics and Bug report ; download

V2.0 (January 2009) : Characteristics and Bug report ; download

V1.3 (April 2008): Characteristics and Bug report ; download

V1.2 (Feb 2008): Characteristics and Bug report

V1.1 (Dec 2007): Characteristics and Bug report

CMEM Input/ Output (top)

Download CMEM I/O sample:

CMEM Input/Output are coded in a modular way, so that the user can choose either ASCII, GRIB or NETCDF I/O format. For any of these I/O type, CMEM is flexible with automatic detection of the Input files sizes. See the description of CMEM I/O and Modelling Platform decription.

A test data set is provided, including input/Output in the three formats (grib, acsii, netcdf) . It is compatible since cmem 1.3. Output files are obtained with CMEM v4.0.

Note that for grib input/output you can use either GRIB API encoding ('gribapi' option, which is the default in cmem v2.1) or GRIBEX encoding ('gribex' option which was the default option until cmem_v1.3, named 'grib' at this stage).

Frequently Asked Questions (top)

What happens when two vegetation types (with different LAIs) are equally dominant in the grid cell?

You need to decide for at most one dominant Low vegetation type and one dominant High vegetation type per grid box in the CMEM input files.

When we use the CIDVEG='ECOCLIMAP' is it based on (H)TESSEL clasification ?

No. When this option is activated, the vegetation classification used is:
0 No vegetation; 1 Decidious forests; 2 Coniferous forests; 3 Rain forests; 4 C3 Grasslands; 5 C4 Grasslands; 6 C3 Crops; 7 C4 Crops.

When I use the 'gribapi option' in cmem_v2.0, I have no probleme with compilation, but running cmem fails with this message (when it starts to write the outputs):
GRIB_API ERROR : grib_new_from_template: Internal error

In your xterm you must do:setenv GRIB_TEMPLATES_PATH /YourPathWhereTemplateFileIs/

It seems to be a problem with the netCDF libraries. Do you probably have some already precompiled netCDF libraries that work well together with CMEM (32bit and 64bit Linux) that you could probably send us for testing?

No CMEM does not use any specific libraries. There must be a problem with your netcdf installation and link to fortran. You have more informations on http://www.unidata.ucar.edu/software/netcdf/docs/netcdf-f90/

A simple test for you to test your installation would be to try to compile and to use a very simple fortran programme which do uses netcdf functions. Examples are given in http://www.unidata.ucar.edu/software/netcdf/docs/netcdf-f90/index.html#Top

Based on this documentation I also put one example here: test_netcdf.F90 to read the foo.nc test file.

In dielsoil_sub.F90 the Dobson model computation of beta does not match with the equation given in the Dobson et al. (1985) paper for the imaginary part. CMEM uses beta = (133.797_JPRM - 0.603_JPRM * sand - 0.166_JPRM * clay) / 100._JPRM, while Dobson et al. indicates that beta = (1.33797 - 0.603 * sand - 0.166 * clay) / 100.

The original Dobson paper had a typo error and was later corrected in Peplinski et al. (1995) (IEEE TGRS, Vol 33) where the expression is given as: beta = (1.33797 - 0.603 * sand - 0.166 * clay), where sand and clay are expressed in fraction. This formulation is used in CMEM where sand and clay contents are expressed in percent.

CMEM TBs are identical in horizontal and vertical polarizations when CMEM is used in C-band. However the 1.4 GHz simulations seem to behave as they should.

Before using CMEM please ensure that soil parameters are properly defined. The soil roughness parameter ip_rgh_surf is defined by default to be 2.2 cm in cmem_setup.F90. It must be replaced by an appropriate value for each case study (lower than 1 in most cases).

CMEM Users (top)

If you are CMEM users and are not in this list just let us know by email so that the CMEM's users list will be updated.

Citing CMEM (top)

CMEM is an ECMWF copyrighted code (Copyright © ECMWF)

We request that you acknowledge the use of CMEM in any publication or report using CMEM. Please refer to one of the citations below. You can also refer to the web page for further information.
We also request that you send us one reprint of any publication that cites the use of CMEM. This helps us to determine the level of use and range of applications of the model we distribute. Thank you.

Holmes, T., M. Drusch, J.-P. Wigneron, S. Lafont, and R. de Jeu, 2008: A global simulation of microwave emission: Error structures based on output from ECMWF's operational Integrated Forecast System, Vol 46(3), pp 846-856 SMOS special issue IEEE Trans. Geosc. Rem. Sens.

Drusch, M., T. Holmes, P. de Rosnay and G. Balsamo, 2009: Comparing ERA-40 based L-band brightness temperatures with Skylab observations: A calibration / validation study using the Community Microwave Emission Model, Vol 10, DOI: 10.1175/2008JHM964.1, J. Hydromet.

de Rosnay P., M. Drusch, A. Boone, G. Balsamo, B. Decharme, P. Harris, Y. Kerr, T. Pellarin, J. Polcher and J.-P. Wigneron, "The AMMA Land Surface Model Intercomparison Experiment coupled to the Community Microwave Emission Model: ALMIP-MEM", J. Geophys. Res., Vol 114, doi:10.1029/2008JD010724, 2009

Community Microwave Emission Modelling Platform (CMEM): http://www.ecmwf.int/research/ESA_projects/SMOS/cmem/cmem_index.html