  The potential habitability of a terrestrial planet is usually defined by the
possible existence of liquid water on its surface. The potential presence of
liquid water depends on many factors such as, most importantly, surface
temperatures. The properties of the planetary atmosphere and its interaction
with the radiative energy provided by the planet's host star are thereby of
decisive importance. In this study we investigate the influence of different
main-sequence stars upon the climate of Earth-like extrasolar planets and their
potential habitability by applying a 3D Earth climate model accounting for
local and dynamical processes. The calculations have been performed for planets
with Earth-like atmospheres at orbital distances where the total amount of
energy received from the various host stars equals the solar constant. In
contrast to previous 3D modeling studies, we include the effect of ozone
radiative heating upon the vertical temperature structure of the atmospheres.
The global orbital mean results obtained have been compared to those of a 1D
radiative convective climate model. The different stellar spectral energy
distributions lead to different surface temperatures and due to ozone heating
to very different vertical temperature structures. As previous 1D studies we
find higher surface temperatures for the Earth-like planet around the K-type
star, and lower temperatures for the planet around the F-type star compared to
an Earth-like planet around the Sun. However, this effect is more pronounced in
the 3D model results than in the 1D model because the 3D model accounts for
feedback processes such as the ice-albedo and the water vapor feedback. Whether
the 1D model may approximate the global mean of the 3D model results strongly
depends on the choice of the relative humidity profile in the 1D model, which
is used to determine the water vapor profile.
