Coefficient file history for RTTOV v11
This page documents the history of changes to coefficient files so that users can understand differences between old and new versions. Only changes since May 2014 are documented. Changes that apply to many coefficient files appear at the top of the page followed by file histories for individual files grouped by sensor type. Individual file histories are linked from the main RTTOV coefficients page in the "Date of file creation" column of the coefficient tables.
General coefficient updates
25/09/2015, all IR v7 and v8 predictor coefficients including hi-res IR sounders
A bug was discovered in the coefficient generation related to the 2m water vapour variable which affects all IR v7 and v8 predictor coefficients generated since RTTOV v11.1. The impact of this on simulated brightness temperatures is illustrated in this document. In addition coefficients for some channels of HIRS, IRAS and MODIS are now Planck-weighted as this improves the fit of the optical depth regression:
- NIMBUS 6 HIRS: channels 9-16 are now Planck-weighted
- NOAA 5-10, 12 HIRS: channels 10 and 12-16 are now Planck-weighted
- NOAA 11, 14 HIRS: channels 12-17 are now Planck-weighted
- NOAA 15-19 HIRS: channels 13-17 are now Planck-weighted
- METOP 1, 2 HIRS: channels 13-17 are now Planck-weighted
- IRAS: channels 14-18 are now Planck-weighted
- MODIS: channels 4-6 (v7/v8 predictor) and channels 23-25 (v9 predictor) are now Planck-weighted
- For "shifted" coefficients the same channels are Planck-weighted as in the non-shifted files
25/09/2015, all MW coefficients
As described in this document, all MW coefficients were regenerated for the release of RTTOV v11.3 to fix some bugs and introduce improved spectroscopy.
- Optical depth predictors are now calculated from water vapour in units of ppmv over dry air to be consistent with the IR coefficients.
- The treatment of gas units was not consistent within the coefficient generation process and this has been fixed.
- Updates to the oxygen line parameters and the 183GHz line half-width.
In addition some changes were made to a few individual instrument coefficient files:
- MWS: some channel pass bands have been updated.
- AMSR-E and AMSR2: very small changes in some channel central wavenumbers due to change in precision (negligible impact).
- SSMIS on DMSP-19: satellite height changed from 850km to 852.8km (negligible impact).
Hi-res IR sounders
rtcoef_nimbus_4_iris.dat, v8 predictors, 101L
- 24/06/2015
- LBL spectral range extended to cover all IRIS channels
- there are some small differences in output radiances in channels within the previous LBL spectral range (up to 20 microns) due to changes in the precision used in the optical depth regression
IR sensors
rtcoef_himawari_8_ahi.dat, v7 predictors, 54L
- 11/06/2014
- updated channel central wavenumbers and SRFs
- channel 7 (index 1 in file) is no longer Planck-weighted
- channel 9 (index 3 in file) is now Planck-weighted
rtcoef_mtg_1_fci.dat, v7 predictors, 54L
- 11/06/2014
- channel 10 (index 2 in file) is no longer Planck-weighted
- there are some small differences in output radiances due to changes in the precision used in the optical depth regression
rtcoef_sentinel3_1_slstr.dat, v7 predictors, 54L
Visible/IR sensors
rtcoef_eos_1_aster.dat, v9 predictors, 54L
- 16/11/2015
- coefficients for IR channels are trained for zenith angles up to ~65 degrees instead of ~84 degrees as for the VIS/NIR channels (reduces errors and larger angles are not required for IR channels on instruments in LEO)
rtcoef_ers_1_atsr.dat, v9 predictors, 54L
- 02/09/2014
- thermal channels trained over 6 secants instead of 14 secants
rtcoef_ers_2_atsr.dat, v9 predictors, 54L
- 02/09/2014
- thermal channels trained over 6 secants instead of 14 secants
rtcoef_envisat_1_atsr.dat, v9 predictors, 54L
- 02/09/2014
- thermal channels trained over 6 secants instead of 14 secants
rtcoef_goes_16_abi.dat, v9 predictors, 54L
- 11/06/2014
- thermal emission no longer calculated for channel 6 (ss_val_chn=2)
- there are some small differences in output radiances due to changes in the precision used in the optical depth regression
rtcoef_himawari_8_ahi.dat, v9 predictors, 54L
- 11/06/2014
- updated channel central wavenumbers and SRFs
- channel 7 is no longer Planck-weighted
- channel 9 is now Planck-weighted
rtcoef_noaa_15_avhrr.dat, v9 predictors, 54L
rtcoef_noaa_16_avhrr.dat, v9 predictors, 54L
rtcoef_noaa_17_avhrr.dat, v9 predictors, 54L
rtcoef_noaa_18_avhrr.dat, v9 predictors, 54L
- 06/09/2015
- coefficients for IR channels are trained for zenith angles up to ~65 degrees instead of ~84 degrees as for the VIS/NIR channels (reduces errors and larger angles are not required for IR channels on instruments in LEO)
rtcoef_noaa_19_avhrr.dat, v9 predictors, 54L
- 17/07/2014
- add missing 1.6 micron channel
- coefficients for IR channels are trained for zenith angles up to ~65 degrees instead of ~84 degrees as for the VIS/NIR channels (reduces errors and larger angles are not required for IR channels on instruments in LEO)
rtcoef_metop_1_avhrr.dat, v9 predictors, 54L
rtcoef_metop_2_avhrr.dat, v9 predictors, 54L
- 06/09/2015
- coefficients for IR channels are trained for zenith angles up to ~65 degrees instead of ~84 degrees as for the VIS/NIR channels (reduces errors and larger angles are not required for IR channels on instruments in LEO)
rtcoef_mtg_1_fci.dat, v9 predictors, 54L
- 11/06/2014
- channel 10 is no longer Planck-weighted
- thermal emission no longer calculated for channel 8 (ss_val_chn=2)
- there are some small differences in output radiances due to changes in the precision used in the optical depth regression
rtcoef_fy3_1_iras.dat, v9 predictors, 54L
- 04/09/2015
- channels 14-18 are now Planck-weighted
rtcoef_eos_1_modis.dat, v9 predictors, 54L
- 04/09/2015
- channels 23-25 are now Planck-weighted
- 11/06/2014
- thermal emission no longer calculated for channel 7 (ss_val_chn=2)
- there are some small differences in output radiances due to changes in the precision used in the optical depth regression
rtcoef_eos_1_modis-shifted.dat, v9 predictors, 54L
- 04/09/2015
- channels 23-25 are now Planck-weighted
- 11/06/2014
- thermal emission no longer calculated for channel 7 (ss_val_chn=2)
- there are some small differences in output radiances due to changes in the precision used in the optical depth regression
rtcoef_eos_2_modis.dat, v9 predictors, 54L
- 04/09/2015
- channels 23-25 are now Planck-weighted
- 11/06/2014
- thermal emission no longer calculated for channel 7 (ss_val_chn=2)
- there are some small differences in output radiances due to changes in the precision used in the optical depth regression
rtcoef_eos_2_modis-shifted.dat, v9 predictors, 54L
- 04/09/2015
- channels 23-25 are now Planck-weighted
- 11/06/2014
- thermal emission no longer calculated for channel 7 (ss_val_chn=2)
- there are some small differences in output radiances due to changes in the precision used in the optical depth regression
rtcoef_landsat_8_oli.dat, v9 predictors, 54L
- 11/06/2014
- thermal emission no longer calculated for channel 7 (ss_val_chn=2)
- changes in channel central wavenumbers (in the 3rd significant figure or smaller)
- there are some small differences in output radiances due to changes in the precision used in the optical depth regression
rtcoef_sentinel3_1_slstr.dat, v9 predictors, 54L
- 08/10/2015
- 11/06/2014
- thermal emission no longer calculated for channel 6 (ss_val_chn=2)
- changes in channel central wavenumbers (in the 4th significant figure or smaller)
- there are some small differences in output radiances due to changes in the precision used in the optical depth regression
rtcoef_jpss_0_viirs.dat, v9 predictors, 54L
- 16/11/2015
- coefficients for IR channels are trained for zenith angles up to ~65 degrees instead of ~84 degrees as for the VIS/NIR channels (reduces errors and larger angles are not required for IR channels on instruments in LEO)
- 11/06/2014
- thermal emission no longer calculated for channel 15 (ss_val_chn=2)
- small changes in channel central wavenumbers (in the 7th significant figure or smaller)
- there are some small differences in output radiances due to changes in the precision used in the optical depth regression
rtcoef_fy2_3_vissr.dat, v9 predictors, 54L
rtcoef_fy2_4_vissr.dat, v9 predictors, 54L
- 06/09/2015
- coefficients for IR channels are trained for zenith angles up to ~65 degrees instead of ~84 degrees as for the VIS/NIR channels (reduces errors and larger angles are not required for IR channels on instruments in LEO)
MW sensors
rtcoef_noaa_18_mhs.dat, v7 predictors, 54L
- 07/05/2014
- central wavenumbers and band correction coefficients corrected (previously were taken from AMSU-B)
- constants used in Planck function updated to be consistent with other coefficient files
rtcoef_noaa_19_mhs.dat, v7 predictors, 54L
- 07/05/2014
- central wavenumbers and band correction coefficients corrected (previously were taken from AMSU-B)
- constants used in Planck function updated to be consistent with other coefficient files