Radiative Transfer for Steam Atmosphere

Overview

• To calculate properties of steam atmosphere for various temperature profiles

Model

• Temperature profile
  • Convective atmosphere is assumed.
  • adiabat profile: IAPWS-95 (IAPWS, 2009)
• Opacity
  • absorption cross section
    • data source
      • HITEMP2010 (Rothman et al., 2010)
      • MT_CKD 2.5 (Mlawer et al., 2012)
    • calculation method
      • line shape: voigt line shape (Kuntz 1997, Ruyten 2004)
      • temperature and pressure dependence of line profile: Rothman et al., 1998 (but, line shift is depending on temperature(similar to LBLRTM))
  • scattering cross section
    • Goldblatt et al., 2013
  • calculation of opacity
    • We prepare absorption cross section table. Required absorption cross section is calculated by cubic spline interpolation.
• Radiative transfer
  • Two stream approximation (Toon et al., 1989)
  • wavenumber range: 0.01 - 20000.0 [cm-1]
  • wavenumber resolution: 0.01 [cm-1]

Setting

• Surface Temperature
  • 250, 300, 400, 600, 800, 1000, 1500, 1700, 2000 [K]
• H2O amount
  • 0.001M, 0.01M, 0.1M, 1M, 5M (M:current ocean mass = 270 [bar])
• grid setting
  • top of atmosphre: 1 [Pa]

Example

• Brightness Temperature: 2.7[bar], 1000[K] IMG
• Optical Depth of all Atmosphere ( vertical axis means log(optical depth) )
  • 0.01M (2.7bar): 600K, 800K,1000K,1500K,1700K,2000K
  • 0.1M (27bar): 600K, 800K,1000K,1500K,1700K,2000K
  • 1M (270bar): 250K,300K,400K,600K, 800K,1000K,1500K,1700K,2000K
  • 5M (1350bar): 800K,1000K,1500K,1700K,2000K
• Outgoing Flux from Top of Atmosphere
  • 0.01M (2.7bar): 600K, 800K,1000K,1500K,1700K,2000K
  • 0.1M (27bar): 600K, 800K,1000K,1500K,1700K,2000K
  • 1M (270bar): 250K,300K,400K,600K, 800K,1000K,1500K,1700K,2000K
  • 5M (1350bar): 800K,1000K,1500K,1700K,2000K
• Brightness Temperature
  • 0.01M (2.7bar): 600K, 800K,1000K,1500K,1700K,2000K
  • 0.1M (27bar): 600K, 800K,1000K,1500K,1700K,2000K
  • 1M (270bar): 250K,300K,400K,600K, 800K,1000K,1500K,1700K,2000K
  • 5M (1350bar): 800K,1000K,1500K,1700K,2000K

Data

• Vertical Profile: Temperature, Upward Flux, Downward Flux
  • 0.01M (2.7bar): 600K, 800K,1000K,1500K,1700K,2000K
  • 0.1M (27bar): 600K, 800K,1000K,1500K,1700K,2000K
  • 1M (270bar): 250K,300K,400K,600K, 800K,1000K,1500K,1700K,2000K
  • 5M (1350bar): 800K,1000K,1500K,1700K,2000K
• Optical Depth of all Atmosphere
  • 0.01M (2.7bar): 600K, 800K,1000K,1500K,1700K,2000K
  • 0.1M (27bar): 600K, 800K,1000K,1500K,1700K,2000K
  • 1M (270bar): 250K,300K,400K,600K, 800K,1000K,1500K,1700K,2000K
  • 5M (1350bar): 800K,1000K,1500K,1700K,2000K
• Outgoing Flux from Top of Atmosphere
  • 0.01M (2.7bar): 600K, 800K,1000K,1500K,1700K,2000K
  • 0.1M (27bar): 600K, 800K,1000K,1500K,1700K,2000K
  • 1M (270bar): 250K,300K,400K,600K, 800K,1000K,1500K,1700K,2000K
  • 5M (1350bar): 800K,1000K,1500K,1700K,2000K
• Brightness Temperature
  • 0.01M (2.7bar): 600K, 800K,1000K,1500K,1700K,2000K
  • 0.1M (27bar): 600K, 800K,1000K,1500K,1700K,2000K
  • 1M (270bar): 250K,300K,400K,600K, 800K,1000K,1500K,1700K,2000K
  • 5M (1350bar): 800K,1000K,1500K,1700K,2000K

References

• Goldblatt et al., 2013, Nature Geoscience, vol.6, 661--667: Low simulated radiation limit for runaway greenhouse climates.
• Kuntz 1997, JQSRT, vol.57, No.6, 819--824: A New Implementation of the Humlicek Algorithm for the Calculation of the Voigt Profile Function.
• Mlawer et al., 2012, Philosophical Transactions of the Royal Society A, vol.370, 2520--2556: Development and recent evaluation of the MT_CKD model of continuum absorption.
• Rothman et al., 1998, JQSRT, vol.60, No.5, 665--710: The HITRAN Molecular Spectroscopic Database and HAWKS (HITRAN Atmospheric Workstation): 1996 edition.
• Rothman et al., 2010, JQSRT, vol.111, 2139--2150: HITEMP, the high-temperature molecular spectroscopic database.
• Ryuten 2004, JQSRT, vol.86, 231--233: Comment on "A new implementation of the Humlicek Algorithm for the calculation of the Voigt Profile Function" by M. Kuntz [JQSRT 57(6) (1997) 819-824].
• The International Association for the Properties of Water and Steam, 2009: Revised Release on the IAPWS Formulation 1995 for the Thermodynamic Properties of Ordinary Water Substance for General and Scientific Use

Acknowledgements

We use MT_CKD continuum model (Mlawer et al., 2012) for calculating molecular continuum absorption.