Fig. 4.2-1

Observed values of `solar constant' (energy flux density of solar radiation arrived at a surface perpendicular to the line between the sun and the earth at the average distance). Unit is W / m². Biases between observing instruments have been adjusted.

The book of "Quaternary Science" includes a figure cited from Fröhlich and Lean (1998). The figure here is drawn by Masuda based on digital data provided by World Radiation Center in Davos, Switzerland (ftp://ftp.pmodwrc.ch/pub/data/irradiance/composite/composite_d25_05_0301.dat; This is the same data as described in the reference above but updated to 15 January 2003.)