Atmospheric blocking and extreme weather frequency patterns associated with solar irradiance forcing during the last 400 years

Although the influence of Sun on climate variability is largely investigated its contribution to extreme weather and climate change remains widely questioned. Because the sample sizes of observed weather and climate extremes are typically too small, we used seasonal resolution paleo-reanalysis data as predictors to extend back in time the field of observed climate extreme indices to reliably identify the solar signal. We reconstructed the field of a two-dimensional atmospheric blocking frequency indicator in the North Atlantic region as well as the field of the frequency of extreme cold temperature and extremely high precipitation days over Europe back to the year 1600. Based on these reconstructions, we show that low (high) solar irradiance winters are associated with more (less) frequent blocking in the Atlantic-European region. This pattern was particularly strong during Maunder and Dalton solar minima. Consistent anomaly patterns are identified for the frequency of extreme low temperature and extremely high precipitation days over Europe. A numerical experiment reveals a significant increase in the blocking frequency in the Atlantic-European region during a Grand Solar Minimum relative to the 1850s solar irradiance levels. This suggests that blocking anomaly patterns associated with total solar irradiance forcing during winter, as derived from observational data, are robust in the perspective of the last four hundred years of blocking and associated weather extreme variability in the North Atlantic region. Therefore, these patterns are useful to estimate the blocking and related weather extremes under various scenarios/predictions of total solar irradiance change during next decades/centuries.