RTTOV-WRF-MPAS

Simulate satellite observation using RTTOV from WRF or MPAS model output

• Input: NetCDF model output
• Output: brightness temperatures or reflectances

Usage

Always call scripts in the same python environment as was used for compiling RTTOV, otherwise import pyrttov will likely fail.

MPAS

The script rttov_mpas.py has two modes of operation:

1. If no observation grid is supplied, we run RTTOV on all MPAS model cells.
2. If supplied an obs_locations_file, we run RTTOV for the observation locations only. The model is interpolated to the observation. The file should have observation locations, satellite angles, and times. See configuration in config_mpas.yaml.

Usage: python rttov_mpas.py <MPAS_input_file> <output_file> --obs_locations_file [path] --obs_time [YYYY-MM-DDTHH:MM:SS] --force

WRF

The WRF script is configured for the SEVIRI instrument and less flexible. Use configuration config_wrf.py and 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, which creates the output file /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.

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-MPAS.git
3. Run cd RTTOV-WRF; pip install -e . in the command line. Dependencies will be installed by the pip command.
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

RTTOV support

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/)