In the final chapter of this book we will briefly treat the radiative influence of clouds on the climate of the Earth. A brief introduction to this topic has already been presented in the first chapter where we have discussed the radiation budget of the Earth. In the chapters that followed we have studied the radiative transfer theory in some detail and have learned how to calculate the radiances and flux densities in the solar and long-wave spectrum.

We have omitted any discussion of measurement programs such as the satellite experiments ERB and ERBE which were specifically devised to study the global radiation budget. A brief description of some of the sophisticated instrumentation used to measure the reflected solar energy and the outgoing long-wave radiation is given by Lenoble (1993) where many references to this topic can be found.

Globally the planet Earth is in radiative equilibrium implying that the reflected solar radiation and the outgoing long-wave radiation are in balance with the incoming solar radiation. If this balance is disturbed by natural or by anthropogenic processes the global climate will be changed. A detailed study of the radiative impact of clouds on the climate is very difficult and can be carried out only with the help of sophisticated climate models.