A low-order model of water vapor, clouds, and thermal emission for tidally locked terrestrial planets

Yang, Jun

doi:10.1088/0004-637X/784/2/155

Title: A low-order model of water vapor, clouds, and thermal emission for tidally locked terrestrial planets

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Abstract

In the spirit of minimal modeling of complex systems, we develop an idealized two-column model to investigate the climate of tidally locked terrestrial planets with Earth-like atmospheres in the habitable zone of M-dwarf stars. The model is able to approximate the fundamental features of the climate obtained from three-dimensional (3D) atmospheric general circulation model (GCM) simulations. One important reason for the two-column model's success is that it reproduces the high cloud albedo of the GCM simulations, which reduces the planet's temperature and delays the onset of a runaway greenhouse state. The two-column model also clearly illustrates a secondary mechanism for determining the climate: the nightside acts as a 'radiator fin' through which infrared energy can be lost to space easily. This radiator fin is maintained by a temperature inversion and dry air on the nightside, and plays a similar role to the subtropics on modern Earth. Since one-dimensional radiative-convective models cannot capture the effects of the cloud albedo and radiator fin, they are systematically biased toward a narrower habitable zone. We also show that cloud parameters are the most important in the two-column model for determining the day-night thermal emission contrast, which decreases and eventually reverses as the stellar fluxmore »« less

Authors:: Yang, Jun

Publication Date:: Tue Apr 01 00:00:00 EDT 2014

OSTI Identifier:: 22357223

Resource Type:: Journal Article

Journal Name:: Astrophysical Journal

Additional Journal Information:: Journal Volume: 784; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X

Country of Publication:: United States

Language:: English

Subject:: 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ALBEDO; APPROXIMATIONS; CAPTURE; DWARF STARS; EMISSION; GENERAL CIRCULATION MODELS; ONE-DIMENSIONAL CALCULATIONS; PLANETS; SATELLITE ATMOSPHERES; SATELLITES; SIMULATION; SPACE; TEMPERATURE INVERSIONS; THREE-DIMENSIONAL CALCULATIONS; WATER; WATER VAPOR

Citation Formats


                    Yang, Jun, and Abbot, Dorian S., E-mail: junyang28@uchicago.edu. A low-order model of water vapor, clouds, and thermal emission for tidally locked terrestrial planets.  United States: N. p., 2014. 
        Web.  doi:10.1088/0004-637X/784/2/155.

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                    Yang, Jun, & Abbot, Dorian S., E-mail: junyang28@uchicago.edu. A low-order model of water vapor, clouds, and thermal emission for tidally locked terrestrial planets.  United States.  https://doi.org/10.1088/0004-637X/784/2/155

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                    Yang, Jun, and Abbot, Dorian S., E-mail: junyang28@uchicago.edu. 2014.  
        "A low-order model of water vapor, clouds, and thermal emission for tidally locked terrestrial planets".  United States.  https://doi.org/10.1088/0004-637X/784/2/155.

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@article{osti_22357223,

  title        = {A low-order model of water vapor, clouds, and thermal emission for tidally locked terrestrial planets},

  author       = {Yang, Jun and Abbot, Dorian S., E-mail: junyang28@uchicago.edu},

  abstractNote = {In the spirit of minimal modeling of complex systems, we develop an idealized two-column model to investigate the climate of tidally locked terrestrial planets with Earth-like atmospheres in the habitable zone of M-dwarf stars. The model is able to approximate the fundamental features of the climate obtained from three-dimensional (3D) atmospheric general circulation model (GCM) simulations. One important reason for the two-column model's success is that it reproduces the high cloud albedo of the GCM simulations, which reduces the planet's temperature and delays the onset of a runaway greenhouse state. The two-column model also clearly illustrates a secondary mechanism for determining the climate: the nightside acts as a 'radiator fin' through which infrared energy can be lost to space easily. This radiator fin is maintained by a temperature inversion and dry air on the nightside, and plays a similar role to the subtropics on modern Earth. Since one-dimensional radiative-convective models cannot capture the effects of the cloud albedo and radiator fin, they are systematically biased toward a narrower habitable zone. We also show that cloud parameters are the most important in the two-column model for determining the day-night thermal emission contrast, which decreases and eventually reverses as the stellar flux increases. This reversal is important because it could be detected by future extrasolar planet characterization missions, which would suggest that the planet has Earth-like water clouds and is potentially habitable.},

  doi          = {10.1088/0004-637X/784/2/155},

  url          = {https://www.osti.gov/biblio/22357223},
  journal      = {Astrophysical Journal},

  issn         = {0004-637X},

  number       = 2,

  volume       = 784,

  place        = {United States},

  year         = {Tue Apr 01 00:00:00 EDT 2014},

  month        = {Tue Apr 01 00:00:00 EDT 2014}

}

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