NOAA/WDS Paleoclimatology - Stoykova et al. 2008 Duhlata Cave, Bulgaria 243KYr Speleothem Luminescence Data

We have confirmed the solar origin of insolation cycles of 11,500, 4400, 3950, 2770, 2500, 2090, 1960, 1670, 1460, 1280, 1195, 1145, 1034, 935, 835, 750 and 610 yrs found in speleothem luminescence by their presence in other indices of the solar wind. The 11,500-yr solar cycle can produce climatic variations similar to those caused by the orbital variations.We discovered a sub-annual cycle of 27 days in one very high-resolution speleothem proxy paleoclimatic record, attributed to solar rotation, which causes the periodic appearance of active zones on the visible solar surface, which are the major emitters of solar wind. Solar wind modulates cosmic ray flux at the Earth, while cosmic rays influence the atmospheric transparency, thus producing a multiplication of solar variations in insolation. Small variations of the solar activity can produce a measurable influence on insolation.