Effect of clouds on emission spectra for Super Venus

TL;DR

This study models how clouds, especially sulfuric acid clouds, affect the emission spectra of super-Venus planets, aiding in the identification of cloud characteristics through spectral features.

Contribution

It demonstrates how cloud altitude, composition, and thermal inversion influence emission spectra, providing a method to identify cloud properties on super-Venus planets.

Findings

High altitude clouds cause featureless spectra without thermal inversion.

Thermal inversion enhances spectral features related to clouds.

Decreasing cloud top altitude increases spectral features.

Abstract

We report a model study on the effects of clouds on emission spectra of super-Venus planets. Our goal is to assess possible ways to identify characteristic spectral features due to clouds. We show that it is possible to distinguish an impact of H2SO4 clouds on the CO2 absorption band at 4.8 micron for temperature profiles with and without a thermal inversion. The thermal inversion can help to distinguish the signal from high altitude clouds (85 km, ~1 mbar). Featureless emission spectra are found for high altitude clouds (85 km, ~1 mbar) with temperature profile without thermal inversion. More spectral features appear in the emission spectra with decreasing cloud top altitudes. The compactness of clouds has an inverse effect on emission spectra than cloud top altitudes. Small cloud scale heights reduce the signal and the CO2 absorption bands become flat.