Exoclimes_Conference_booklet1

consistently calculates the ground temperature. We present early results from studies
looking at the role of clouds on the dynamics and habitability of terrestrial exoplanets
orbiting M-dwarfs. Using these models, we will identify fundamental dynamical
mechanisms that drive their atmospheres and constrain their thermal structures, which will
inform future observations of transiting terrestrial exoplanets, particularly at secondary
eclipse.
Modeling of Habitable Planets - the Underlying Atmospheric Dynamics
Cevahir Kilic! — University of Bern!
Instrumentation to detect new planets develops continually and enabled the scientific
community to characterize exoplanets in terms of physical parameters, such as size and
mass, as well as identify possible atmospheres. Furthermore, the CHEOPS satellite
program will provide the possibility for an improved characterization also in terms of
habitability of exoplanets. The increasing number of newly detected planets raises issues
of possible other habitable worlds.
To investigate the atmospheric dynamics of habitable planets, we use a hierarchy of
general circulation models (GCMs). In a first step, we carry out these simulations using a
three-dimensional atmospheric GCM of intermediate complexity, the so-called Planet
Simulator.
For this study, sensitivity simulations varying different basic parameters of the planet are
performed to explore the range of habitability. Each simulation is carried out over 30 model
years. In doing so, we have modified gravity, radius, sidereal day, atmospheric
composition, distance to the star, and obliquity of the ecliptic. These simulations uses an
Earth-like environment (e.g., Earth land mask), which allows us to compare our
investigations with Earth observations. The range of surface temperatures determines the
habitability of a planet. Our simulations show, inter alia, that an increase in radius leads to
a reduction of the global mean temperature. We also find an impact on the amplitude of
the seasonality given by the gravity of the planet. The difference between maximum and
minimum temperature is enhanced with increasing gravity. Additionally, the variation of the
gravity changes the atmospheric structure: an increased gravity leads to a more stable
atmosphere above 700 hPa and to generally stronger wind fields and lower surface
temperatures on the planet. Furthermore, basic dynamical features such as the number of
jet streams will be assessed in the sensitivity simulations. The next steps also include a
model adaption with different land masks (e.g., aqua-planet).
A new perspective on the inner edge of the habitable zone: 3D modeling of runaway
greenhouse processes on Earth like planets
Jeremy Leconte — LMD (Paris) / CITA (Toronto)
Because current exoplanets detection methods are biased toward shorter-period orbits,
most planets discovered to date have a higher equilibrium temperature than the Earth. If
water is available at the surface, the amount of water vapor is expected to increase as the
planet warms, enhancing, in turn, the atmospheric greenhouse effect.
It has been shown that, above a certain critical insolation, this destabilizing greenhouse
feedback can "runaway" until all the oceans are evaporated. It has also been suggested
that warming may sufficiently increase stratospheric humidity to cause oceans to escape
to space before the runaway greenhouse occurs. However, the value of the critical
insolations triggering these processes remain uncertain because they have so far been
evaluated with unidimensional models that cannot account for dynamical effects and cloud
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