RTTOV v12 Code Updates and Known Issues

RTTOV v12 Code Updates

Updates and bug fixes to RTTOV v12 will be published here.

Known bugs and issues

Please report any bugs you find in RTTOV using the NWP SAF Helpdesk. The official release packages for each version don’t contain the bug fixes or updates listed here under that version so you should apply any fixes provided below. Bugs in earlier versions have been fixed in later versions.

Show/Hide the table of known bugs and other updates in RTTOV v12.3.

DateType/StatusDescription
16/04/2019Bug - fixedAffects: solar simulations (excluding MFASIS simulations) for multiple profiles where some, but not all, profiles have solar zenith angles above 85.3 degrees (the maximum for which RTTOV can compute solar radiation). There is no problem if all profiles passed to RTTOV have solar zenith angles which exceed this limit or if all profiles have solar zenith angles below this limit.

Issue: this particular case is not checked during the local satellite/solar path geometry calculations and a numerical error results. For profiles with large solar zenith angles above the limit RTTOV should return zero radiances.

Fix: download this tarball, extract it in the src/main/ directory, and recompile RTTOV (a clean compilation is not necessary). This fix can be applied to RTTOV v12.2 as well.
16/04/2019Bug - fixedAffects: VIS/IR cloud simulations with the simple cloud overlap option (cldstr_simple) and the new grid_box_avg_cloud option both true (v12.3 only).

NB The simple cloud overlap option generates one clear and one cloudy column with a single effective cloud fraction computed as the maximum cfrac value in the layers from the top of atmosphere down to the pressure specified in the cldstr_low_cloud_top option. It is intended for use in very specific scenarios and in the general case it can have a very detrimental effect on the accuracy of simulations. It is therefore not recommended unless you really know what you are doing. This bug does not affect simulations using the default maximum/random cloud overlap so the vast majority of users will be unaffected.

Issue: when the grid_box_avg_cloud option is true the input grid-box-layer-average cloud concentrations are divided by the cloud fraction inside RTTOV to obtain the cloud concentration of the cloudy fraction of each layer. The code always divided the cloud concentrations by the corresponding layer cfrac which is correct for the maximum/random overlap scheme. However, for the simple overlap scheme the cloud concentrations should be divided by the calculated effective profile cloud fraction instead.

Fix: download this tarball, extract it in the src/main/ directory, and recompile RTTOV (a clean compilation is not necessary).
04/04/2019Bugs - fixedAffects: HTFRTC Jacobian model (v12.3 only).

Issues:
- Tskin Jacobians are zero
- Variable gas Jacobians (water vapour, ozone, etc) are incorrect if the gas units are not kg/kg
- The emissivity Jacobians are output in emissivity_k%emis_out instead of emissivity_k%emis_in, the latter being consistent with RTTOV.

Fix: download this file to src/main/ and recompile RTTOV (a clean compilation is not necessary).
01/04/2019Bug - fixedAffects: new Baran 2018 ice optical property parameterisation (v12.3 only).

Issue: a bug in the code means that the optical property parameterisation is not implemented correctly. The impact can be quite variable, but is especially large for visible/near-IR channels. This bug does not affect the pre-existing Baran 2014 parameterisation.

Fix: download this tarball, extract it in the src/main/ directory, and recompile RTTOV (a clean compilation is not necessary). This bug fix affects the output from the test_rttov12_hires.sh and test_multi_instrument.sh test scripts. Updated test reference data are available: download this tarball and extract it in the rttov_test/ directory.

Show/Hide the table of known bugs and updates for RTTOV v12.2 which have been fixed/implemented in RTTOV v12.3. Bugs listed above may also affect v12.2.

Show/Hide the table of known bugs and updates for RTTOV v12.1 which have been fixed/implemented in RTTOV v12.2. Bugs listed above may also affect v12.1.