Secular trends in annual income of solar radiation to Earth within 3000 B.C. to 2999 A.D. with increment 1/12 of tropical year (beginning corresponds to the vernal equinox).



Fig. 6. Secular trends in annual income of solar radiation to Earth within 3000 B.C. to 2999 A.D. with increment 1/12 of tropical year (beginning corresponds to the vernal equinox). The chart is approximated by a 6^th degree polynomial