Chart Crime Alert: An old trick is vertical axis compression to...

Chart Crime Alert:
An old trick is vertical axis compression to exaggerate functional variance.

In this case the sun's flux at the earth's surface (i.e., the Solar Constant) is shown by the graph to range between around 1360.8 W/sq metre and 1361.5 W/sq metre,

i.e. an degree of accuracy of +/- 0.03%
(Note not 3%,. but three hundredths of one percent!)

If you know how the solar constant was derived, you'd know that even remotely to this degree of accuracy, even when dealing with short periods of time, such as days or weeks, is pure BS because the solar function is influenced by the apparent brightness of the Sun, i.e., it;'s luminosity, as well as the inverse square law of the distance to the Sun, which is not a constant because of the eccentricity (e = 0.0167) of the Earth's orbit around the sun.

As for going back 150 years a deriving solar constant accurate to +/- 0.03% , absolute horse manure.

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