scostep 2010 (stp12) - Leibniz-Institut für Atmosphärenphysik an der ...

STP12 Abstracts
Berlin, 12 - 16 July 2010
SCOSTEP Symposium 2010
Solar UV and the predictability of climatic zonation
Vita-Finzi Claudio
Natural History Museum London
UV emission fluctuates much more markedly than the rest of the irradiance spectrum over the
~11 year (Schwabe) cycle and it triggers temporary shifts in components of the global
circulation, including the Hadley cells, the jet streams and the intertropical convergence zone.
Better understanding of the origins of this and other UV periodicities thus offers scope for
improved forecasting of terrestrial and space weather. For example, a 27-day effect which is
conventionally attributed to the Sun’s rotation, and hence viewed as primarily a photospheric
effect, may in fact derive primarily from steady rotation of the Sun’s radiative zone rather
than the vagaries of sunspot and facula distribution. In addition, advances in the analysis of
cosmogenic isotopes reveals cumulative effects which overshadow more flamboyant but
shortlived events. Thus the 14 C and 10 Be evidence of ice cores and marine sediments appears
to indicate a progressive increase in solar irradiance over the last 30,000 years which was
repeatedly subject to century-scale reversals, including the Maunder Minimum, and which,
like the Schwabe, may be manifested in the disposition of the atmospheric circulation rather
than in a mean global temperature. As the 27-day signal shows, fossil and documentary
records of UV fluctuations may in turn serve as windows into the solar interior.