Numéro |
J. Phys. IV France
Volume 121, December 2004
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Page(s) | 61 - 86 | |
DOI | https://doi.org/10.1051/jp4:2004121003 |
J. Phys. IV France 121 (2004) 61-86
DOI: 10.1051/jp4:2004121003
The role of clouds in the climate system
M. QuanteGKSS Research Center, Institute for Coastal Research, 21502 Geesthacht, Germany
Abstract
Clouds are important for global climate since they
have a strong impact on solar and terrestrial radiation as well as on the
formation of precipitation. The different types of clouds in the atmosphere
are linked to the climate system by a multitude of dynamical and
thermodynamical processes including numerous feedback mechanisms. In
present-day climate, on average, clouds cool our planet, the net cloud
radiative forcing at the top of the atmosphere is about -20 Wm-2. One
of the most interesting questions concerning clouds is: how will they
respond to a change in climate? A slight change in cloud amount or a shift
in the vertical distribution of clouds might have a considerable impact on
the energy budget of the Earth. The Third Assessment Report of the
Intergovernmental Panel on Climate Change (IPCC) states clearly that cloud
processes and related feedbacks are among the physical processes leading to
large uncertainties in the prediction of future climate. The main reason for
this is that many microphysical and dynamical processes controlling the life
cycle and radiative properties of clouds are not adequately implemented in
global climate models. The interaction of aerosols and clouds and the
resulting radiative forcing (indirect and semi-direct aerosol effect) is one
of the major fields of active cloud research at present. This chapter
introduces various aspects of the cloud-climate relation and summarizes the
discussions of topics currently under scientific debate.
© EDP Sciences 2004