Figure 5. Solar radiation. Sunspot number from 1610 to 1970 and solar total irradiance from 1600 to 2000 (upper right) (after Lean et al., 1995; Pang and Yau, 2002, with permission of American Geophysical Union). Total solar magnetic flux emanating from the sun from 1875 to 1990 (lower right) (from Lockwood et al., 1999, with permission of Nature -- http://www.nature.com/help/reprints_and_permissions/permit_form.html).