Spectral files
This document contains details on the applicability of spectral files to various atmospheric compositions. All spectral files are located in the following directory on Discover:
/discover/nobackup/projects/giss/spectral_files
ROCKE-3D will assume that the spectral file is located in this directory, and it is only necessary to specify the spectral subdirectory and file in the rundeck as follows:
spectral_file_lw='sp_lw_ga7/sp_lw_ga7'
aer_opt_prop_lw='sp_lw_ga7/aer_lw_ga7.nc'
If needed, the main spectral file directory can be changed with the spectral_dir rundeck variable:
spectral_dir='/discover/nobackup/projects/giss/spectral_files'
Please see the References section for references to the spectroscopic data used to generate the spectral files.
Unless otherwise stated, all spectral files have the following temperature and pressure ranges:
Temperature range for Planck table: 1 K to 500 K
Temperature range for opacities: 100 K to 400 K
Pressure range for opacities: Up to 1 bar
However, the accuracy of long-wave spectral files will decrease for temperatures higher than about 310 K.
All spectral files use the MT_CKD 3.0 water vapor continuum unless stated otherwise.
Spectral file descriptions in gray have been depreciated.
MT_CKD water vapor continuum:
Mlawer, E. J. et al. Phil. Trans. Roy. Soc. A, 370, 1-37, 2012 (https://doi.org/10.1098/rsta.2011.0295)
CKD water vapor continuum:
Clough, S. A. et al. Atmos. Res., 23, 229-241, 1989 (https://doi.org/10.1016/0169-8095(89)90020-3)
CAVIAR water vapor continuum:
Ptashnik, I. V. et al. Journal of Geophysical Research: Atmospheres 116.D16, 2011 (https://doi.org/10.1029/2011JD015603)
HITRAN:
Rothman, L. S. et al. Journal of Quantitative Spectroscopy and Radiative Transfer 130, 4-50, 2013 (https://doi.org/10.1016/j.jqsrt.2013.07.002)
CO2 sub-Lorentzian line shapes:
Perrin, M. Y. & Hartmann, J. M. J. Quant. Spectrosc. Radiat. Transf. 42, 311–317, 1989 (https://doi.org/10.1016/0022-4073(89)90077-0)
Wordsworth, R. et al. Icarus 210.2, 992-997, 2010 (https://doi.org/10.1016/j.icarus.2010.06.010)
CO2-CO2 CIA:
Gruszka, M. & Borysow, A. Mol. Phys. 93, 1007–1016, 1998 (https://doi.org/10.1080/002689798168709)
Baranov, Y.I. et al. J. Mol. Spectrosc. 228, 432–440, 2004 (https://doi.org/10.1016/j.jms.2004.04.010)
Wordsworth, R. et al. Icarus 210.2, 992-997, 2010 (https://doi.org/10.1016/j.icarus.2010.06.010)
N2-CH4, N2-N2, N2-H2, H2-CH4 and H2-H2 CIA:
Richard, C. et al. Journal of Quantitative Spectroscopy and Radiative Transfer 113.11, 1276-1285, 2012 (https://doi.org/10.1016/j.jqsrt.2011.11.004)
CO2-H2 and CO2-CH4 CIA:
Wordsworth, R. et al. Geophysical Research Letters 44.2, 665-671, 2017 (https://doi.org/10.1002/2016GL071766)
Generalized Rayleigh scattering
Functional fits of refractive indices as a function of wavelength taken from https://refractiveindex.info. For references for individual gases see the SOCRATES source file src/modules_gen/refract_re_ccf.f90. On discover the full path to this file is:
/discover/nobackup/projects/giss/socrates/modele_branch/src/modules_gen/refract_re_ccf.f90
The spectral files in this section are located in the subdirectories sp_lw_ga7 and sp_sw_ga7. The default Met Office spectral files for Global Atmosphere configuration (GA) 7.0 are:
sp_lw_ga7: Long-wave spectral file with 9 bands provided with SOCRATES. Suitable for an atmosphere with present day Earth gas amounts. Uses the CAVIAR water vapor continuum.
Temperature range for Planck polynomial fit: 160 to 330 K
Temperature range for opacities: Mid-latitude summer P-T profile +- 50 K
Pressure range for opacities: Up to 1 bar.
High resolution reference: sp_lw_300_jm2
sp_sw_ga7: Short-wave spectral file with 6 bands provided with SOCRATES. Suitable for an atmosphere with present day Earth gas amounts for a planet orbiting the Sun. Uses the CAVIAR water vapor continuum.
Temperature range for opacities: Mid-latitude summer P-T profile +- 50 K
Pressure range for opacities: Up to 1 bar.
High resolution reference: sp_sw_260_jm2
As the above two spectral files have Earth-centric opacity and Planck P-T tables, I have created the following spectral files with an extended temperature range:
sp_lw_ga7_dsa: Same as sp_lw_ga7, but with an extended temperature grid.
High resolution reference: sp_lw_350_jm2dsa
sp_sw_ga7_dsa: Same as sp_sw_ga7, but with an extended temperature grid.
High resolution reference: sp_sw_280_jm2dsa
NB! Changing the stellar spectrum as described in the SOCRATES in ROCKE-3D user guide is not possible with these files.
The spectral files in this section are located in the subdirectories sp_lw_dsa and sp_sw_dsa.
sp_lw_12_dsa: Increased precision for atmospheres with higher temperatures and humidity (especially for M-star spectra) than present day Earth. More robust when zeroing out absorbers. Significantly slower than e.g. sp_sw_ga7_dsa.
High resolution reference: sp_lw_350_dsa
sp_sw_21_dsa: Increased precision in water vapor absorption in the near-IR with more bands. More robust when zeroing out absorbers. Also suited for planets around M-stars with potentially large specific humidities, but significantly slower than e.g. sp_sw_ga7_dsa.
High resolution reference: sp_sw_280_dsa
The default spectral files are sp_lw_ga7_dsa and sp_sw_ga7_dsa.
The below spectral files are located in the directories sp_lw_dsa_ar and sp_sw_dsa_ar.
sp_lw_12_dsa_ar: Long-wave spectral file suitable for an Archean Earth-like atmosphere. Valid for GHG concentrations up to 104 ppmv CO2 and 104 ppmv CH4. Accuracy is ~ 1W/m2 for temperatures ~< 310 K.
High resolution reference: sp_lw_350_dsa_ar
sp_sw_6_dsa_ar: NOT RECOMMENDED. Short-wave spectral file suitable for an Archean Earth-like atmosphere. Valid for GHG concentrations up to 104 ppmv CO2 and 2x103 ppmv CH4. Significantly lower accuracy (~ 10 W/m2 for Sun-like stars, ~ 20 W/m2 for M-stars), but faster, than sp_sw_29_dsa_ar. Note that for present day Earth CH4 levels (or lower) sp_sw_6_dsa_ar_lowch4 is recommended to improve the computation speed.
High resolution reference: sp_sw_280_dsa_ar
sp_sw_29_dsa_ar: Short-wave spectral file suitable for an Archean Earth-like atmosphere. Valid for GHG concentrations up to 104 ppmv CO2 and 104 ppmv CH4. Accuracy is ~0.5 W/m2 for Sun-like stars, ~3 W/m2 for M-stars. Note that for present day Earth CH4 levels (or lower) sp_sw_6_dsa_ar_lowch4 is recommended to improve the computation speed.
High resolution reference: sp_sw_280_dsa_ar
The below spectral files are located in the directories sp_lw_dsa_ar and sp_sw_dsa_ar.
sp_sw_6_dsa_ar_lowch4: Short-wave spectral file suitable for an Archean Earth-like atmosphere. Valid for GHG concentrations up to 2x103 ppmv CO2 and 2 ppm CH4.
High resolution reference: sp_sw_280_dsa_ar
The below spectral files are located in the directories sp_lw_dsa_arcc and sp_sw_dsa_arcc. Valid between 104 and 105 ppmv CO2, and up to 104 ppmv CH4. Includes CO2-CO2 CIA, CO2 sub-Lorentzian line wings and CO2 self-broadening.
Uses generalized Rayleigh scattering, i.e. pN2, pO2 and pAr must be set.
sp_lw_17_dsa_arcc: Long-wave spectral file suitable for an Archean Earth-like atmosphere. Accuracy is ~ 1 W/m2 for temperatures ~< 310 K.
High resolution reference: sp_lw_350_dsa_arcc
sp_sw_35_dsa_arcc: Short-wave spectral file suitable for an Archean Earth-like atmosphere. Accuracy is ~1 W/m2 for Sun-like stars, ~3 W/m2 for M-stars.
High resolution reference: sp_sw_280_dsa_arcc
The below spectral files are located in the directories sp_lw_dsa_arva and sp_sw_dsa_arva. Valid between 104 and 105 ppmv CO2 (likely also lower CO2 concentrations, but please verify for your particular atmosphere), up to 1000 ppmv N2O, and up to 10 ppmv CH4. The short-wave file is only suitable for Sun-like stellar spectra. Includes CO2-CO2 CIA, CO2 sub-Lorentzian line wings and CO2 self-broadening.
Uses generalized Rayleigh scattering, i.e. pN2, pO2 and pAr must be set.
sp_lw_17_dsa_arva: Long-wave spectral file suitable for an Archean Earth-like atmosphere with N2O. High resolution reference: sp_lw_350_dsa_arva
sp_sw_18_dsa_arva: Short-wave spectral file suitable for an Archean Earth-like atmosphere with N2O.
High resolution reference: sp_sw_280_dsa_arva
The below files are located in the directories sp_lw_dsa_ar10bar and sp_sw_dsa_ar10bar. They are suitable for atmospheres dominated by a mixture of N2 and H2, with up to 1% CO2 and CH4. Valid for surface pressures up to 10 bar. Note that for H2 fractions above >~ 10% pressure broadened widths should be adjusted due to H2-broadening, however, this is not included in the below files.
Contains six different kinds of collision induced absorption (CIA): N2-CH4, N2-N2, N2-H2, H2-CH4 and H2-H2 from HITRAN, and H2-CO2 from Robin Wordsworth. Should also have included N2-CO2 CIA, but could not find the data in the literature.
Both due to the CIA and generalised Rayleigh scattering used, pN2, pO2 (should be zero), pAr and pH2 must be set.
sp_lw_15_dsa_ar10bar: Long-wave spectral file suitable for N2/H2-dominated atmospheres with up to 1% CO2 and CH4. Accuracy is ~ 1 W/m2 for temperatures ~< 310 K.
High resolution reference: sp_lw_350_dsa_ar10bar
sp_sw_43_dsa_ar10bar: Short-wave spectral file suitable for N2/H2-dominated atmospheres with up to 1% CO2 and CH4. Accuracy is ~< 5 W/m2 for all stars.
High resolution reference: sp_sw_280_dsa_ar10bar
The below spectral files are located in the directories sp_lw_dsa_mars and sp_sw_dsa_mars. They are suitable for CO2-dominated atmospheres with > 90% CO2. Valid for surface pressures up to 10 bar. Includes CO2-CO2 CIA, CO2 sub-Lorentzian line wings and CO2 self-broadening. Note that, even though CO2 is broadened by CO2 in the below files, H2O is still broadened by “air”.
Uses generalized Rayleigh scattering, i.e. pN2, pO2 and pAr must be set.
sp_lw_17_dsa_mars: Long-wave spectral file suitable for Mars-like CO2-dominated atmospheres. Accuracy is ~ 1 W/m2 for temperatures ~< 310 K.
High resolution reference: sp_lw_350_dsa_mars
sp_sw_42_dsa_mars: Short-wave spectral file suitable for Mars-like CO2-dominated atmospheres. Accuracy is ~< 5 W/m2 for all stars. Uses generalized Rayleigh scattering, i.e. pN2, pO2 and pAr must be set.
High resolution reference: sp_sw_280_dsa_mars
The below files are located in the directories sp_lw_dsa_pm and sp_sw_dsa_pm. They are suitable for CO2-dominated atmospheres (> 80% CO2), with up to 1% CH4, and the remaining atmosphere being some mix of N2 and H2. Valid for surface pressures up to 10 bar. Includes CO2 sub-Lorentzian line wings and CO2 self-broadening. Note that, even though CO2 is broadened by CO2 in the below files, H2O and CH4 is still broadened by “air”.
The long-wave file contains CO2-CO2, CO2-CH4, CO2-H2 and N2-N2 CIA. N2-CH4, H2-H2, H2-CH4 and N2-H2 were found to be negligible and are not included. The short-wave file contains CO2-CO2, CO2-H2 and H2-H2 CIA. CO2-CH4, N2-CH4, N2-N2, N2-H2, H2-CH4 CIA were found to be negligible and are not included. N2-CO2 CIA is not included in either, and its importance has not been evaluated due to a lack of data in the literature.
Both due to the CIA and generalised Rayleigh scattering used, pN2, pO2 (should be zero), pAr and pH2 must be set.
sp_lw_16_dsa_pm: Long-wave spectral file suitable for CO2-dominated (> 80%) atmospheres with up to 1% CH4, the remaining being some mix of N2 and H2. Accuracy is ~ 1 W/m2 for temperatures ~< 310 K.
High resolution reference: sp_lw_350_dsa_pm
sp_sw_46_dsa_pm: Short-wave spectral file suitable for CO2-dominated (> 80%) atmospheres with up to 1% CH4, the remaining being some mix of N2 and H2. Accuracy is ~ 1 W/m2 for temperatures ~< 310 K.
High resolution reference: sp_sw_280_dsa_pm
The below files are located in the directories sp_lw_dsa_titan and sp_sw_dsa_titan. They have been developed specifically for the atmosphere of Titan (star, composition and temperature range), and includes CH4, N2-CH4, N2-N2 and N2-H2 CIA. Valid for N2-dominated atmospheres with surface pressures up to 2 bar, with up to 5% CH4, 1% H2. The opacities are tabulated between 10-5 and 2 bar (54 points), temperatures between 40 and 200 K (16 points). The Planck function is tabulated between 1 and 300 K.
Both due to the CIA and generalised Rayleigh scattering used, pN2, pO2 (should be zero), pAr (should be zero) and pH2 must be set.
These spectral files do not contain water cloud optical properties, and consequently radiative effects of water clouds need to be turned off in any run using them. This is done in the rundeck by setting l_cloud=0 in the parameter section.
sp_lw_10_dsa_titan: Long-wave spectral file suitable for Titan. Accuracy is ~0.1 W/m2.
High resolution reference: sp_lw_250_dsa_titan
sp_sw_14_dsa_titan: Short-wave spectral file suitable for Titan. Accuracy is ~0.1 W/m2 for Titan irradiation levels (~15 W/m2 at TOA at substellar point).
High resolution reference: sp_sw_280_dsa_titan
Appended to short-wave spectral file names are the name of the star. Sometimes star names are abbreviated for convenience, this section provides an overview of the abbreviations used.
When adding stars to this list, please also provide a reference.
sun Solar spectrum (Lean 2012)
sun_0.715gya Solar spectrum at 0.715 Gya (Mark Claire)
sun_2.9gya Solar spectrum at 2.9 Gya (Mark Claire)
sun_3.8gya Solar spectrum at 3.8 Gya (Mark Claire, Judith Lean)
gj876 Gliese 876 (Domagal-Goldman et al. 2014)
k186 Kepler-186 (Allard et al. 2012)
pc: Proxima Centauri (VPL team via Nancy Kiang)
hd22049 HD 22049 (Segura et al. 2003)
trappist1 TRAPPIST-1 (BT-Settl with Teff = 2600 K, logg = 5, Fe/H = 0)
k1649 Kepler-1649 (BT-Settl with Teff = 3200 K, logg = 5, Fe/H = 0)