Literature Review to Stratospheric Temperatures and Water Loss from Moist Greenhouse Atmospheres of Earth-like Planets
Earth 2.0
Literature Review to Stratospheric Temperatures and Water Loss from Moist Greenhouse Atmospheres of Earth-like Planets
Earth 2.0

Literature Review to Stratospheric Temperatures and Water Loss from Moist Greenhouse Atmospheres of Earth-like Planets

Abstract Explanation:

  • A radiative-convective climate model predicts stratospheric temperatures and water vapor concentrations in ozone-free atmospheres, suggesting water loss from planets with surface temperatures above 350 K [1].
  • The presence of a moist greenhouse atmosphere can lead to water loss through photodissociation and hydrogen escape, supporting the hypothesis for water loss from Venus and similar exoplanets receiving high stellar radiation.

Introduction Summary:

  • The circumstellar habitable zone (HZ) is defined as the region where liquid water can exist on a rocky planet, with the inner edge determined by the onset of a moist greenhouse or a runaway greenhouse.
  • Recent studies have shown variations in stratospheric temperatures and water vapor concentrations in different climate models, impacting the understanding of water loss mechanisms from planets with high surface temperatures.

Methods Used in the Paper:

  • The study utilized a radiative-convective climate model to calculate stratospheric temperatures and water vapor concentrations in different atmospheric conditions.
  • The 1D model was updated to handle runaway greenhouse atmospheres and predict vertical profiles of temperature and water vapor.
  • A time-stepping algorithm was employed to reach steady-state solutions and perform forward and inverse mode calculations to determine solar flux needed to sustain surface temperatures.
  • Modifications were made to the 1D model to perform calculations that are a hybrid of forward and inverse modes, resetting surface temperatures and determining atmospheric cold traps.

Results and Discussion:

  • Different climate models show variations in stratospheric temperatures and water vapor concentrations based on surface temperatures, impacting water loss mechanisms from planets with high temperatures.
  • The 1D radiative-convective climate model was used to predict vertical profiles of temperature and water vapor, providing insights into the behavior of atmospheres under varying conditions.
  • Changes in atmospheric CO2 concentrations were found to influence stratospheric temperatures, with implications for understanding the warming effects of CO2 in cold atmospheres.

Conclusion:

  • The study highlights the importance of considering stratospheric temperatures and water vapor concentrations in climate models to better understand water loss processes on planets with different atmospheric conditions.

Limitations of the Paper:

  • The 1D model used in the study cannot simulate all processes included in a 3D model, limiting the comprehensive understanding of atmospheric dynamics.
  • The model assumptions, such as excluding O2 and O3, may oversimplify the atmospheric composition and interactions, potentially affecting the accuracy of the results.