9:00 AM - 9:15 AM
[MIS18-01] Dependence of the onset of the runaway greenhouse effect on the surface water distribution for Earth-like planets
Keywords:Habitable planets, Runaway greenhouse effect, Water planets
We investigated the effect of the distribution of surface water on the runaway greenhouse threshold for Earth-sized planets using a three-dimensional dynamic atmosphere model. We consider three types of the surface water distribution on a planet: a latitudinally uniform water distribution, a longitudinally uniform water distribution, and water distribution with different water amounts assuming the planetary topography (Earth and Mars). For longitudinally uniform water distributions, we also consider cases for concentrated distribution and equally dispersed distribution even if areas of water distribution are same. We consider a 1-bar atmosphere whose composition is similar to the current Earth’s atmosphere.
As results, when the water distribution becomes larger, the runaway greenhouse threshold becomes lower and closes to that for an aqua planet, which is covered with ocean globally. We found that the runaway greenhouse threshold for an equally dispersed water distribution is lower than that for a concentrated water distribution even if areas of water distribution are same. This is because the atmosphere for the former globally keeps wetter than that for the latter does.
In this presentation, we summarize the dependence of the onset of the runaway greenhouse effect on the surface water distribution of Earth-like planets.