Clouds in Wacky Climates

From Exoplanet Reading Group

Dorian Abbot

to be presented at the Chapman conference on planetary atmospheres

Abstract: Clouds have a huge impact on the climate of a planet. On Earth, if the clouds forgot that part of their job is to reflect solar energy, we would suffer a runaway greenhouse and end up like Venus. If clouds forgot that part of their job is to absorb infrared radiation emitted by the surface and contribute to the greenhouse effect, we would enter global glaciation. Although they are very important for climate, clouds are very difficult to model and represent the largest source of uncertainty in climate modeling. This results both from insufficient resolution to resolve cloud-scale circulation and incomplete understanding of cloud microphysics. Cloud simulation is therefore the main reason our current models aren't better, and is a critical area to attack if we want to create generalized GCMs that could be easily applied to different planets (the clouds might not be water clouds in this case). In this talk I will discuss how we can use the models we have to gain insight into cloud behavior in climates vastly different from modern Earth. The two examples I will focus on are the Snowball Earth episodes and tidally locked super-Earths near the inner edge of the habitable zone of M-stars.