RTTOV v11 Coefficient File Downloads

RTTOV v11 Coefficient File Downloads

Additional information about coefficient files (NB that page has been updated for the latest version of RTTOV so not all information may apply to RTTOV v11 coefficients).

Script for downloading coefficient files (run from within rtcoef_rttov11/ directory)

Hi-res IR sounder optical depth coefficients

All hi-res IR sounder coefficient files share these characteristics:

  • Based on LBLRTM v12.2 line-by-line model
  • No Planck-weighted channels

RTTOV v10 compatibility:

  • All ASCII optical depth coef files may be used with RTTOV v10, but new functionality such as NLTE is not available in v10
  • Cloud coef files are v10-compatible (they are the same as the v10 files)
  • Aerosol coef files and PC coef files cannot be read by RTTOV v10

Downloads

  • All files are linked in the table below.
  • Due to the large size of the hi-res sounder files HDF5 is the preferred format for them. Please contact the NWP SAF Helpdesk to request an ASCII version of a file if required. See the user guide for information on converting between coefficient file formats and extracting subsets of channels from coefficient files.
  • HDF5 files were created using the HDF5 compression so your HDF5 library must have been compiled against zlib to read these files: this usually happens automatically when building HDF5.
  • Currently the test scripts expect the HDF5 versions of the v7 and v9 predictor AIRS, IASI files and the associated aerosol, cloud and PC files.
  • The same cloud and aerosol coefficient files are used with v7, v8 and v9 predictor optical depth coefficient files.
  • Extract to folders as follows:
    • v7 predictor 54L rtcoef files – extract to rtcoef_rttov11/rttov7pred54L/
    • v7 predictor 101L rtcoef files – extract to rtcoef_rttov11/rttov7pred101L/
    • v8 predictor 101L rtcoef files – extract to rtcoef_rttov11/rttov8pred101L/
    • v9 predictor 101L rtcoef files – extract to rtcoef_rttov11/rttov9pred101L/
    • All cloud/aerosol files – extract to rtcoef_rttov11/cldaer/
    • All PC files – extract to rtcoef_rttov11/pc/
SensorLevelsPredictors

version
Trace

gases
Solar?NLTE?PC?FilenameDate of file
creation
Associated aerosol
coef filename
Associated cloud
coef filename
Associated PC
coef filename
AIRS547O3NYNrtcoef_eos_2_airs.H521/07/2015scaercoef_eos_2_airs.H5sccldcoef_eos_2_airs.H5-
AIRS1017O3NYNrtcoef_eos_2_airs.H521/07/2015As aboveAs above-
AIRS1018O3, CO2NYNrtcoef_eos_2_airs.H523/07/2015As aboveAs above-
AIRS1019O3, CO2, CO, N2O, CH4YYYrtcoef_eos_2_airs.H501/02/2014As aboveAs abovepccoef_eos_2_airs.H5 (clear-sky)
pccoef_eos_2_airs_landsea.H5 (clear-sky, all surfaces)

See notes below.
CrIS547O3NYNrtcoef_jpss_0_cris.H521/07/2015scaercoef_jpss_0_cris.H5sccldcoef_jpss_0_cris.H5-
CrIS1017O3NYNrtcoef_jpss_0_cris.H521/07/2015As aboveAs above-
CrIS1018O3, CO2NYNrtcoef_jpss_0_cris.H523/07/2015As aboveAs above-
CrIS1019O3, CO2, CO, N2O, CH4YYNrtcoef_jpss_0_cris.H523/05/2014As aboveAs above-
CrIS FSR547O3NYNrtcoef_jpss_0_cris-fsr.H521/07/2015---
CrIS FSR1017O3NYNrtcoef_jpss_0_cris-fsr.H521/07/2015---
CrIS FSR1018O3, CO2NYNrtcoef_jpss_0_cris-fsr.H523/07/2015---
CrIS FSR1019O3, CO2, CO, N2O, CH4YYNrtcoef_jpss_0_cris-fsr.H517/12/2014---
IASI547O3NYNrtcoef_metop_2_iasi.H521/07/2015scaercoef_metop_2_iasi.H5sccldcoef_metop_2_iasi.H5-
IASI1017O3NYNrtcoef_metop_2_iasi.H521/07/2015As aboveAs above-
IASI1018O3, CO2NYNrtcoef_metop_2_iasi.H523/07/2015As aboveAs above-
IASI1019O3, CO2, CO, N2O, CH4YYYrtcoef_metop_2_iasi.H501/02/2014As aboveAs abovepccoef_metop_2_iasi.H5 (clear-sky, sea-only)
pccoef_metop_2_iasi_landsea.H5 (clear-sky, all surfaces)

See notes below.
IASI-NG1017O3NNNrtcoef_metopsg_1_iasing.H521/07/2015---
IASI-NG1018O3, CO2NNNrtcoef_metopsg_1_iasing.H523/07/2015---
IASI-NG1019O3, CO2, CO, N2O, CH4YNYrtcoef_metopsg_1_iasing.H501/02/2014--pccoef_metopsg_2_iasing.H5 (clear-sky, sea-only)

See notes below.
IRIS1018O3, CO2NNNrtcoef_nimbus_4_iris.H523/07/2015---

Updated PC coefficients

  • New principal components coefficients use different predictor channel sets to previous versions of the files. You can obtain the appropriate predictor channel set in your own code using the rttov_get_pc_predictindex subroutine as demonstrated in src/test/example_pc_fwd.F90.
  • The older sea-only coefficient files must only be used over sea surfaces with calcemis(:) set to true (this is not enforced by RTTOV v11.3).
  • The new all-surface “landsea” PC coefficients can be used for all surface types: it is recommended to set calcemis(:) to true over sea surfaces and to use the IR emissivity atlas for land and sea-ice surfaces, but this is not strictly mandatory.
  • These latter global PC coefficients can only be used over land and sea-ice surfaces with RTTOV v11.3 (such simulations will fail with v11.1 and v11.2).

Metop-B IASI coefficients
The Metop-B (i.e. metop_1) IASI optical depth coefficient file is identical to the Metop-A (metop_2) coefficient file except that the satellite ID is 1 (for Metop-B) instead of 2 (for Metop-A). If you read the coefficients by filename you can use the same file for either instrument. However if distinct files are required an ASCII Metop-A optical depth coefficient file can be used to generate a Metop-B file using the Perl script make_metopb_iasi.pl as follows:

$ ./make_metopb_iasi.pl < rtcoef_metop_2_iasi.dat

where rtcoef_metop_2_iasi.dat is any Metop-A ASCII IASI coefficient file. This creates a new file rtcoef_metop_1_iasi.dat in the current directory.
The IASI cloud/aerosol scattering and PC coefficient files are identical for Metop-A and Metop-B.

MTG-IRS coefficients

Experimental MTG-IRS coefficients have been generated using transmittances from simulated IASI spectra and a Hamming apodisation function.

SensorLevelsPredictors

version
Trace

gases
Solar?NLTE?PC?FilenameDate of file
creation
Associated aerosol
coef filename
Associated cloud
coef filename
Associated PC
coef filename
MTG-IRS (experimental)1017O3NNNrtcoef_mtg_1_irs-hamming.H521/07/2015---
MTG-IRS (experimental)1018O3, CO2NNNrtcoef_mtg_1_irs-hamming.H523/07/2015---

IR optical depth coefficients

All IR coefficient files share these characteristics:

  • Based on LBLRTM v12.2 line-by-line model (except SSU which is based on LBLRTM v12.0)
  • 54 levels (except SSU which is on 51 levels)
  • Not solar compatible
  • Not NLTE compatible
  • Not PC compatible

RTTOV v10 compatibility:

  • The new SSU PMC shift files are not v10-compatible
  • All other rtcoef files are v10-compatible
  • All cloud coef files are v10-compatible (they are the same as the v10 files)
  • Aerosol coef files are not v10-compatible
  • Note that the SLSTR and FY2-2 VISSR instrument names and IDs and the GMS imager instrument ID have changed since v10

Downloads

SensorPlanck

weighted
Predictors

version
Trace

gases
FilenameDate of file
creation
Associated aerosol
coef filename
Associated cloud
coef filename
(A)ATSR*Y7O3rtcoef_ers_x_atsr.dat
rtcoef_envisat_1_atsr.dat
21/07/2015scaercoef_ers_x_atsr.dat
scaercoef_envisat_1_atsr.dat
sccldcoef_ers_x_atsr.dat
sccldcoef_envisat_1_atsr.dat
AATSR-shifted
Info on AATSR 12 um anomaly
Y7O3rtcoef_envisat_1_atsr-shifted.dat29/11/2016--
ABIY7O3rtcoef_goes_xx_abi.dat31/08/2016scaercoef_goes_xx_abi.dat-
AHIY7O3rtcoef_himawari_x_ahi.dat21/07/2015
13/05/2016
scaercoef_himawari_x_ahi.datsccldcoef_himawari_x_ahi.dat
ASTERY7O3rtcoef_eos_1_aster.dat21/07/2015scaercoef_eos_1_aster.dat-
AVHRRY7O3rtcoef_noaa_xx_avhrr.dat
rtcoef_metop_x_avhrr.dat
21/07/2015scaercoef_noaa_xx_avhrr.dat
scaercoef_metop_x_avhrr.dat
sccldcoef_noaa_xx_avhrr.dat
sccldcoef_metop_x_avhrr.dat
ECOSTRESSY7O3rtcoef_iss_1_ecostres.dat01/09/2016--
FCIY7O3rtcoef_mtg_1_fci.dat21/07/2015scaercoef_mtg_1_fci.dat-
GMS imagerY7O3rtcoef_gms_5_imager.dat21/07/2015scaercoef_gms_5_imager.datsccldcoef_gms_5_imager.dat
GOES imagerY7O3rtcoef_goes_xx_imager.dat21/07/2015scaercoef_goes_xx_imager.datsccldcoef_goes_xx_imager.dat
GOES sounderGOES 4-7
only
7O3rtcoef_goes_xx_sounder.dat21/07/2015scaercoef_goes_xx_sounder.datsccldcoef_goes_xx_sounder.dat
HIRSN7O3rtcoef_noaa_xx_hirs.dat
rtcoef_metop_x_hirs.dat
27/07/2015scaercoef_noaa_xx_hirs.dat
scaercoef_metop_x_hirs.dat
sccldcoef_noaa_xx_hirs.dat
sccldcoef_metop_x_hirs.dat
HIRSN8O3, CO2rtcoef_noaa_xx_hirs.dat
rtcoef_metop_x_hirs.dat
rtcoef_nimbus_6_hirs.dat
27/07/2015As aboveAs above
HIRS shifted
spectral response
N7O3rtcoef_noaa_xx_hirs-shifted.dat
rtcoef_metop_x_hirs-shifted.dat
27/07/2015scaercoef_noaa_xx_hirs-shifted.dat
scaercoef_metop_x_hirs-shifted.dat
-
HIRS shifted
spectral response
N8O3, CO2rtcoef_noaa_xx_hirs-shifted.dat
rtcoef_metop_x_hirs-shifted.dat
27/07/2015As above-
IIRY7O3rtcoef_calipso_1_iir.dat21/07/2015scaercoef_calipso_1_iir.dat-
INSAT-3D(R) imagerY7O3rtcoef_insat3_x_imager.dat19/01/2016
12/11/2016
--
INSAT-3D(R) sounderY7O3rtcoef_insat3_x_sounder.dat19/01/2016
13/11/2016
--
IRASN7O3rtcoef_fy3_1_iras.dat22/07/2015scaercoef_fy3_1_iras.dat-
MetImageY7O3rtcoef_metopsg_1_metimage.dat21/07/2015--
MIY7O3rtcoef_coms_1_mi.dat21/07/2015scaercoef_coms_1_mi.datsccldcoef_coms_1_mi.dat
MODISN7O3rtcoef_eos_x_modis.dat22/07/2015scaercoef_eos_x_modis.datsccldcoef_eos_x_modis.dat
MODIS shifted
spectral response
N7O3rtcoef_eos_x_modis-shifted.dat22/07/2015scaercoef_eos_x_modis-shifted.dat-
MRIRY7O3rtcoef_nimbus_3_mrir.dat21/07/2015--
MRIRY8O3, CO2rtcoef_nimbus_3_mrir.dat23/07/2015--
MSUMRY7O3rtcoef_meteor-m_1_msumr.dat21/07/2015scaercoef_meteor-m_1_msumr.dat-
MTSAT imagerY7O3rtcoef_mtsat_x_imager.dat21/07/2015scaercoef_mtsat_x_imager.datsccldcoef_mtsat_x_imager.dat
MVIRIY7O3rtcoef_meteosat_x_mviri.dat21/07/2015scaercoef_meteosat_x_mviri.datsccldcoef_meteosat_x_mviri.dat
MVISRN7O3rtcoef_fy1_x_mvisr.dat21/07/2015scaercoef_fy1_x_mvisr.datsccldcoef_fy1_x_mvisr.dat
SEVIRIY7O3rtcoef_msg_x_seviri.dat21/07/2015scaercoef_msg_x_seviri.datsccldcoef_msg_x_seviri.dat
SGLIN7O3rtcoef_gcom-c_1_sgli.dat28/11/2016--
SLSTRY7O3rtcoef_sentinel3_1_slstr.dat08/10/2015scaercoef_sentinel3_1_slstr.dat-
SSU 51LN8O3, CO2rtcoef_noaa_xx_ssu.dat02/08/2012 (noaa-5,6)
09/08/2012 (noaa-7-9,14)
29/08/2012 (noaa-11)
--
SSU 51L with variable
cell pressure
N8O3, CO2rtcoef_noaa_xx_ssu_pmcshift.dat10/01/2013--
THIRY7O3rtcoef_nimbus_x_thir.dat19/05/2016--
TIRSN7O3rtcoef_landsat_8_tirs.dat21/07/2015scaercoef_landsat_8_tirs.dat-
TMN7O3rtcoef_landsat_x_tm.dat21/07/2015scaercoef_landsat_x_tm.dat-
VIIRSY7O3rtcoef_jpss_0_viirs.dat21/07/2015scaercoef_jpss_0_viirs.datsccldcoef_jpss_0_viirs.dat
VISSRY7O3rtcoef_fy2_x_vissr.dat21/07/2015scaercoef_fy2_x_vissr.datsccldcoef_fy2_x_vissr.dat
VTPRN7O3rtcoef_noaa_x_vtpr.dat21/07/2015--

* The ERS-1 ATSR coefficient file contains coefficients for 6 channels: 1-3 are the standard channels (12, 11, 3.7 microns respectively) and 4-6 are additional coefficients for the 12 micron channel using spectral responses valid at different sensor temperatures. The corresponding aerosol coefficients have been generated using this coefficient file and as such contain data for the 6 channels in the rtcoef file. However the cloud coefficient file only contains parameters for the 3 standard channels (1-3, with 1 being the 12 micron channel). Therefore if you wish to use the cloudy coefficients for ERS-1 ATSR you should first extract channels 1-3 from the rtcoef file to a separate file using the rttov_conv_coef.exe executable.

Visible/IR solar-compatible optical depth coefficients

All visible/IR solar coefficient files share these characteristics:

  • Based on LBLRTM v12.2 line-by-line model
  • 54 levels
  • v9 predictors
  • Solar compatible
  • Not NLTE compatible
  • Not PC compatible
  • No associated aerosol/cloud coefficient files
  • Note that you can run IR-only simulations using these files, but you may find the v7 predictor files above give better results for IR channels.
  • Channel numbering for IR channels may differ to the v7 predictor files above: check the coefficient file headers, the user guide or the sensor tables page.

RTTOV v10 compatibility:

  • These files are not v10-compatible

Downloads

SensorPlanck

weighted
Trace

gases
FilenameDate of file
creation
(A)ATSRYO3rtcoef_ers_x_atsr.dat
rtcoef_envisat_1_atsr.dat
02/09/2014
AATSR-shifted
Info on AATSR 12 um anomaly
YO3rtcoef_envisat_1_atsr-shifted.dat29/11/2016
ABIYO3rtcoef_goes_xx_abi.dat01/09/2016
AHIYO3rtcoef_himawari_x_ahi.dat11/06/2014
13/05/2016
ASTERYO3rtcoef_eos_1_aster.dat16/11/2015
AVHRRYO3rtcoef_metop_x_avhrr.dat
rtcoef_noaa_xx_avhrr.dat
rtcoef_noaa_19_avhrr.dat
06/09/2015 (Metop 1/2)

18/08/2014 (NOAA 5-14)
06/09/2015 (NOAA 15-18)
17/07/2014 (NOAA 19)
FCIYO3rtcoef_mtg_1_fci.dat11/06/2014
GOES imagerYO3rtcoef_goes_xx_imager.dat28/03/2013
INSAT-3DR imagerYO3rtcoef_insat3_5_imager.dat13/11/2016
IRASNO3rtcoef_fy3_1_iras.dat04/09/2015
MetImageYO3rtcoef_metopsg_1_metimage.dat07/07/2015
MIYO3rtcoef_coms_1_mi.dat28/03/2013
MODISNO3rtcoef_eos_x_modis.dat04/09/2015
MODIS shifted spectral responseNO3rtcoef_eos_x_modis-shifted.dat04/09/2015
MTSAT imagerYO3rtcoef_mtsat_x_imager.dat28/03/2013
OLINO3rtcoef_landsat_8_oli.dat11/06/2014
SEVIRIYO3rtcoef_msg_x_seviri.dat28/03/2013 (MSG 1-3)

05/12/2014 (MSG 4)
SLSTRYO3rtcoef_sentinel3_1_slstr.dat08/10/2015
VIIRSYO3rtcoef_jpss_0_viirs.dat16/11/2015
VISSRYO3rtcoef_fy2_x_vissr.dat06/09/2015

MW optical depth coefficients

All MW sensor coefficient files share these characteristics:

  • Based on Liebe 89/92 LbL model
  • All on 54 levels except for the Zeeman files
  • v7 predictors
  • No Planck-weighted channels
  • No optional trace gases
  • Cloud liquid water is an optional input
  • Not solar compatible
  • Not NLTE compatible
  • Not PC compatible

RTTOV v10 compatibility:

  • All rtcoef files are v10-compatible
  • All mietable files are v10-compatible
  • The only caveat is that the AMSR-E instrument name and the AMSR2 instrument ID and name have changed since v10 (see note at the top of this page)

Downloads

  • Files for all MW sensors – extract to rtcoef_rttov11/rttov7pred54L/
  • Mie tables are linked in the table below – extract to rtcoef_rttov11/mietable/

Updated Mie tables (10/09/2013):
The original RTTOV-SCATT Mie coefficients produced unrealistically high amounts of scattering from snow hydrometeors at 30-50 GHz and insufficient scattering at 150-183 GHz. The new coefficients address this problem by representing snow hydrometeors as three-dimensional snowflakes rather than Mie spheres. While it is possible to improve Mie sphere results by tuning the snow particle density, it is difficult to improve results at all frequencies simultaneously. The new snow hydrometeor optical properties are based on the “sector snowflake” from the Liu (2008) database of discrete dipole computations for nonspherical ice particles. The new particle shape was chosen because it produces the best fit between observations and ECMWF simulations across frequencies from 10 to 183 GHz.

References:

  • Liu, G. (2008). A database of microwave single-scattering properties for nonspherical ice particles. Bulletin of the American Meteorological Society, 89(10), 1563-1570.
  • Geer, A.J. and F. Baordo (2014). Improved scattering radiative transfer for frozen hydrometeors at microwave frequencies. Atmos. Meas. Tech., 7, 1839-1860, doi:10.5194/amt-7-1839-2014
SensorZeeman
compatible
FilenameDate of file
creation
Associated Mietable
filename
AltiKaNrtcoef_saral_1_altika.dat26/05/2016mietable_saral_altika.dat
AMRNrtcoef_jason_2_amr.dat26/05/2016-
AMSR-ENrtcoef_eos_2_amsre.dat26/05/2016mietable_eos_amsre.dat
AMSR2Nrtcoef_gcom-w_1_amsr2.dat26/05/2016mietable_gcom-w_amsr2.dat
AMSU-ANrtcoef_noaa_xx_amsua.dat
rtcoef_metop_x_amsua.dat
rtcoef_eos_2_amsua.dat
26/05/2016mietable_noaa_amsua.dat
mietable_metop_amsua.dat
mietable_eos_amsua.dat
AMSU-A Zeeman (44L)Yrtcoef_noaa_xx_amsua_zeeman.dat
rtcoef_metop_x_amsua_zeeman.dat
rtcoef_eos_2_amsua_zeeman.dat
04/07/2006As above
AMSU-B
Nrtcoef_noaa_xx_amsub.dat
24/05/2017***mietable_noaa_amsub.dat
ATMSNrtcoef_jpss_0_atms.dat26/05/2016mietable_jpss_atms.dat
GMINrtcoef_gpm_1_gmi.dat26/05/2016mietable_gpm_gmi.dat
HSBNrtcoef_eos_2_hsb.dat26/05/2016-
ICI*, **Nrtcoef_metopsg_1_ici.dat26/05/2016-
MADRASNrtcoef_meghatr_1_madras.dat26/05/2016mietable_meghatr_madras.dat
MHS
Nrtcoef_noaa_xx_mhs.dat
rtcoef_metop_x_mhs.dat
24/05/2017***mietable_noaa_mhs.dat
mietable_metop_mhs.dat
MSUNrtcoef_noaa_xx_msu.dat26/05/2016-
MTVZA-GYNrtcoef_meteor-m_2_mtvzagy.dat26/05/2016mietable_meteor-m_mtvzagy.dat
MWHSNrtcoef_fy3_1_mwhs.dat26/05/2016mietable_fy3_mwhs.dat
MWHS2Nrtcoef_fy3_3_mwhs2.dat10/08/2018mietable_fy3_mwhs2.dat
MWINrtcoef_metopsg_1_mwi.dat26/05/2016mietable_metopsg_mwi.dat
MWRNrtcoef_ers_x_mwr.dat
rtcoef_envisat_1_mwr.dat
26/05/2016mietable_ers_mwr.dat
mietable_envisat_mwr.dat
MWRINrtcoef_fy3_1_mwri.dat
rtcoef_fy3_3_mwri.dat
26/05/2016mietable_fy3_mwri.dat
MWS**Nrtcoef_metopsg_1_mws.dat26/05/2016mietable_metopsg_mws.dat
MWTSNrtcoef_fy3_1_mwts.dat26/05/2016mietable_fy3_mwts.dat
MWTS2Nrtcoef_fy3_3_mwts2.dat10/08/2018mietable_fy3_mwts2.dat
SAPHIRNrtcoef_meghatr_1_saphir.dat26/05/2016mietable_meghatr_saphir.dat
SMMRNrtcoef_nimbus_7_smmr.dat26/05/2016-
SSM/INrtcoef_dmsp_xx_ssmi.dat26/05/2016mietable_dmsp_ssmi.dat
SSMISNrtcoef_dmsp_xx_ssmis.dat26/05/2016mietable_dmsp_ssmis.dat
SSMIS Zeeman (83L)Yrtcoef_dmsp_xx_ssmis_zeeman.dat13/01/2011As above
SSM/T2Nrtcoef_dmsp_xx_ssmt2.dat26/05/2016-
TMINrtcoef_trmm_1_tmi.dat26/05/2016mietable_trmm_tmi.dat
WindsatNrtcoef_coriolis_1_windsat.dat26/05/2016mietable_coriolis_windsat.dat

* ICI coefficients are preliminary: channel specifications may change. Work is planned to validate the spectroscopic data used at frequencies above 200GHz.
** FASTEM and TELSEM have not been trained for frequencies above 200GHz and so should be used with caution for such channels: this applies to most ICI channels and MWS channel 24.
*** The AMSU-B and MHS coefficient files generated in May 2016 did not include band correction coefficients unlike previous versions of these files. The AMSU-B and MHS files in the tarball linked above now include the band correction coefficients (these files have been converted from their RTTOV v12 equivalents).

Coefficient regression limits

RTTOV coefficients are trained using a set of diverse profiles which cover a wide range of values for each atmospheric variable. The fast optical depth calculations can be expected to be accurate for input profiles which lie within the profile “envelopes” defined by the minimum and maximum values for each profile variable.

By default RTTOV checks the input profile against a set of profile regression limits: it can either warn if the regression limits are exceeded or clip the values to the limits where the limits are exceeded (if the apply_reg_limits option is set to TRUE). For some time it has been the practice in RTTOV to set the regression limits to +/-10% of the profile envelope for temperature and +/-20% of the profile envelope for each gas. For highly variable gases (such as water vapour) this may be reasonable, but for less variable gases (such as CO2) the limits should probably be less permissive. The aim is to address this for the next version of RTTOV.

The tables below show the current regression limits defined in the RTTOV coefficient files. This information is contained within each coefficient file.

Show/Hide the table of 54-level regression limits.

Show/Hide the table of 101-level regression limits.

Show/Hide the table of 51-level regression limits (SSU only).