Climate signature of solar irradiance variations: analysis of long-term instrumental, historical, and proxy data
The signature of solar irradiance variations on decadal-to-centennial climate variability is analysed by means of statistical analysis of long-term instrumental, historical, and proxy data sets. Solar variations associated with the Schwabe, Hale, and Gleissberg cycles are detected by their spatial patterns in sea-surface temperature and sea-level pressure. Different statistical methods for instrumental and proxy data show that the mode related to solar irradiance fluctuations on multi-decadal time scales (Gleissberg cycle) is distinct from the Atlantic multi-decadal mode associated with ocean circulation changes. From this, one can infer the degree to which solar variability has contributed to long-term temperature variations during the instrumental and pre-instrumental era.