This paper to appear is a very nice review of solar-earth interactions, including atmospheric electricity, by T. Dudok de Wit, J. Watermann.
The Sun provides the main energy input to the terrestrial atmosphere, and yet the impact of solar variability on long-term changes remains a controversial issue. Direct radiative forcing is the most studied mechanism. Other much weaker mechanisms, however, can have a significant leverage, but the underlying physics is often poorly known.
We review the main mechanisms by which solar variability may impact the terrestrial atmosphere, on time scales ranging from days to millennia. This includes radiative forcing, but also the effect of interplanetary perturbations and energetic particle fluxes, all of which are eventually driven by the solar magnetic field.
Three main conclusions for further research are proposed:
To extend GCMs:
There are several important working fronts as far as the Sunâ€“Earth connection
is concerned. Most GCMs whose development started in the lower atmosphere still
largely ignore the upper part of the atmosphere on which solar variability has the
largest impact. One obvious issue is therefore the upward extension of these models,
and a better description of the mechanisms by which the upper layers may couple
to the stratosphere and eventually to the troposphere. This also involves a better
understanding on how solar variability affects regional climate data. On the other
hand, GCM models like the CITP which started from the thermosphere, face the
challenge of an appropriate downward extension to the stratosphere (and eventually
The second is UV:
A second issue is the definition of reference spectral irradiance in the EUV and UV
bands for different levels of solar activity. These bands have an important leverage of
the middle atmosphere and the reconstruction of past levels is still lacking today. In
all these reconstruction attempts, however, one should be careful against inbreeding
Finally, the mechanism of cosmic ray flux effect on clouds:
A third issue is the understanding of the microphysics associated with atmospheric
electricity and in particular the quantitative role of ions and electrons for stimulating
the production of water vapour condensation nuclei. All three issues involve a much
closer interaction between the space and atmospheric communities, which is definitely
the highest priority of all.