the brückner-egeson-lockyer cycle is a climatic cycle of approximately 30-40 years. originally described on the basis of periodic flooding events in southern australia that were correlated with sunspot activity by charles egeson. it was supported by william j.s. lockyer and later by eduard brückner. the initials "bel" or paratridecadal cycles have since been suggested to explain various other long-term cycles including those affecting economics, human physiology, and historical events.