Climatic Data - Climate Change: Identification and Projections - page 23

Lines labelled lean0 and lean1 come from the reference [LEA 04]. Lines
timv13 and timv15 were determined by G. Kopp [KOP 05] using PMOD
composites, respectively based on versions TIM V13 and TIM V15 of
TIM/SORCE (Total Irradiance Monitor, system fitted on the NASA Solar
Radiation and Climate Experiment satellite).
The differences are great. The line labelled lean0 is almost proportional
to the annual average number of sun spots. The other three include
corrections known as Ephemeral Region Background 7 . They also rely on the
solar models established by comparison with stars similar to our sun. The
authority on the subject is Judith Lean, leader of the IPCC experts on solar
matters, and principal or secondary author of the four reconstructions above.
Ultimately, these corrections amplify the low frequency components of the
Wolf index, with ratios ranging from 1 (for lean 0) to 5 (for lean1).
Therefore, this represents a dynamic linear correction rather than a non-
linear algebraic correction.
Furthermore, another reconstruction covering four centuries can also be
referred to (Figure 2.10), which is not included in Figure 2.9, the data from
which we have not collected. It comes from Shapiro et al . [SHA 11] and
enhances the ER background effect almost two-fold compared to lean1,
under the name of solar modulation potential.
Figure 2.10. Total irradiance reconstructed by Shapiro
7 The “ephemeral regions”, discovered in 1973, are small magnetic dipoles which disappear
before they are able to turn into spots, but the activity of which has an effect on both the TSI
and the solar magnetic field.