RTTOV-WRF

Simulate SEVIRI satellite channels from WRF output

• Input: wrfout file (NetCDF format) written by WRF
• Output: brightness temperatures or reflectances

Usage examples

Use on command line: NetCDF output

Usage: python rttov_wrf.py /path/to/wrfout (VIS|IR|both)

For example, python rttov_wrf.py /somepath/wrfout_d01_2008-07-30_12:00:00 both

creates /somepath/RT_wrfout_d01_2008-07-30_12:00:00.nc

Option: Use VIS to get VIS 0.6 µm reflectance, IR to get WV 6.2 µm, 7.3 µm and IR 10.8 µm brightness temperature or both to get all channels. You can add or remove channels in rttov_wrf.py.

Use within python: Xarray output

from rttov_wrf import call_pyrttov
#config = setup_IR()
config = setup_VIS()  

ds = xr.open_dataset(wrfout_path)
times = ds.Time

for t in times:
    rad = call_pyrttov(ds.sel(Time=t), config)

Run all ensemble members wrfout files from one forecast init (12z) at 13z with:

python run_pattern.py /path_to_exp/2008-07-30_12\:00/*/wrfout_d01_2008-07-30_13\:00\:00

Install

1. Download and compile RTTOV from nwpsaf.eu.
2. Download RTTOV-WRF for example by running git clone https://github.com/lkugler/RTTOV-WRF.git
3. Run cd RTTOV-WRF; pip install -e . in the command line
4. Set paths in paths.py
5. optional: configure the python script rttov_wrf.py, it sets various assumptions for radiative transfer.
6. when running rttov_wrf.py, ensure that you have loaded the same libraries which you used to install RTTOV. For me, this is intel-mpi intel netcdf netcdf-fortran zlib hdf5 (on VSC: module purge; module load intel-mpi/2019.3 intel/19.1.0 netcdf/4.7.0-intel-19.0.5.281-75t52g6 netcdf-fortran/4.4.5-intel-19.0.5.281-qye4cqn zlib/1.2.11-intel-19.1.0.166-hs6m2qh hdf5/1.10.5-intel-19.0.5.281-qyzojtm)

In order to run, it needs:

1. compiled RTTOV / pyrttov (the python wrapper); with the path of pyrttov in PYTHONPATH (is ensured in rttov_wrf.py)
2. installed RTTOV-WRF (including dependencies)
3. loaded libraries for RTTOV

Dependencies

Will be installed by the pip command.

Note:

If you receive an ImportError similar to this one

ImportError: libpython3.7m.so.1.0: cannot open shared object file: No such file or directory

at line import pyrttov, then your python can not find the pyrttov module. You must call rttov_wrf.py with the same python as was used for compiling RTTOV.

Documentation

For the configuration of RTTOV or in case there are errors with RTTOV, consult the documentation of RTTOV or the RTTOV-python-wrapper. (https://nwp-saf.eumetsat.int/site/software/rttov/documentation/)