Placing limits on long-term variations in quiet-Sun irradiance and their contribution to total solar irradiance and solar radiative forcing of climate

Lockwood, Mike; Ball, William T.

doi:10.1098/rspa.2020.0077

Cited by 22 publications

(25 citation statements)

References 63 publications

(167 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The cap on the rise in TSI since the Maunder minimum derived here, 2.0 ± 0.7 W m −2 , encloses all the current estimates (Coddington et al, 2016; Dasi‐Espuig et al, 2016; Egorova et al, 2018; Judge et al, 2012; Lockwood & Ball, 2020; Schrijver et al, 2011; Shapiro et al, 2011; Steinhilber et al, 2009; Tapping et al, 2007; Wu et al, 2018) except the range of 3 to 6.3 W m −2 indicated by Shapiro et al (2011), the reassessment of their model by Judge et al (2012), and CHRONOS (Egorova et al, 2018) (Figure 1b). We consider the upper limit established here to be more reliable than the existing estimates.…”

Section: Comparison To Other Estimates Of the Change In Tsi Since Thesupporting

confidence: 86%

“…The other model‐based estimates (Coddington et al, 2016; Dasi‐Espuig et al, 2016; Steinhilber et al, 2009; Tapping et al, 2007; Wu et al, 2018) are markedly weaker and relatively consistent with one another, indicating a rise of between 0.3 and 0.9 W m −2 (Figure 1b). In another recent study, Lockwood and Ball (2020) concluded, from an analysis of the measurements and models of TSI over the past two solar cycles, that it cannot be excluded from the uncertainty in this data that TSI might have been 0.4 W m −2 lower to 0.75 W m −2 higher during the Maunder minimum. Furthermore, there is a claim that the last cycle minimum in 2008 might be representative of the Maunder minimum (Schrijver et al, 2011).…”

Section: Introductionmentioning

confidence: 86%

“…The long‐term or secular trend in solar irradiance since preindustrial times and how this variability is distributed in wavelength are of particular interest for their relevance to the overall influence of the Sun on the Earth's climate over the past centuries (Solanki et al, 2013). In this article, our focus will be on the particular issue that current estimates of the secular change in the wavelength‐integrated total solar irradiance (TSI) since the 16th century diverge significantly, ranging from a drop of 0.75 W m −2 to a rise of 6.3 W m −2 (Coddington et al, 2016; Dasi‐Espuig et al, 2016; Egorova et al, 2018; Judge et al, 2012; Lockwood & Ball, 2020; Schrijver et al, 2011; Shapiro et al, 2011; Steinhilber et al, 2009; Tapping et al, 2007; Wu et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

“…This implies that TSI rose since the Maunder minimum by the same margin as it did since 2008, about 0.1 W m −2 . By current estimates, since the Maunder minimum, TSI could have risen by more than 3 W m −2 (Egorova et al, 2018; Judge et al, 2012; Shapiro et al, 2011) or by less than 1 W m −2 (Coddington et al, 2016; Dasi‐Espuig et al, 2016; Steinhilber et al, 2009; Schrijver et al, 2011; Tapping et al, 2007; Wu et al, 2018) or even declined instead (Lockwood & Ball, 2020).…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

The Dimmest State of the Sun

Yeo

Solanki

Krivova

et al. 2020

Geophysical Research Letters

View full text Add to dashboard Cite

How the solar electromagnetic energy entering the Earth's atmosphere varied since preindustrial times is an important consideration in the climate change debate. Detrimental to this debate, estimates of the change in total solar irradiance (TSI) since the Maunder minimum, an extended period of weak solar activity preceding the industrial revolution, differ markedly, ranging from a drop of 0.75 W m −2 to a rise of 6.3 W m −2. Consequently, the exact contribution by solar forcing to the rise in global temperatures over the past centuries remains inconclusive. Adopting a novel approach based on state-of-the-art solar imagery and numerical simulations, we establish the TSI level of the Sun when it is in its least-active state to be 2.0 ± 0.7 W m −2 below the 2019 level. This means TSI could not have risen since the Maunder minimum by more than this amount, thus restricting the possible role of solar forcing in global warming. Plain Language Summary How the amount of energy the Earth receives from the Sun varied since preindustrial times is an important consideration in the climate change debate. Detrimental to this debate, it is not known whether the Sun grew brighter or dimmer since the 16th century, and by how much. As a consequence, the exact contribution by fluctuations in the brightness of the Sun to the rise in global temperatures over the past centuries remains controversial. It is established that the Sun was particularly inactive over much of the 16th century. Adopting a novel approach based on state-of-the-art solar imagery and computer models, we determined the brightness of the Sun when it is in its least-active state possible. This places a strict limit on how much the Sun could have grown brighter since the lull in solar activity over the 16th century, restricting the possible role the Sun could have played in global warming. Since the reliable measurement of solar irradiance only started in 1978 (Kopp, 2014), climate simulations rely on models of solar irradiance variability to provide the requisite historical solar forcing input. Except at RESEARCH LETTER

show abstract

Section: Comparison To Other Estimates Of the Change In Tsi Since Thesupporting

confidence: 86%

Section: Introductionmentioning

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The Dimmest State of the Sun

Yeo

Solanki

Krivova

et al. 2020

Geophysical Research Letters

View full text Add to dashboard Cite

show abstract

“…Results from the various SI models show considerable disagreement in the long-term evolution of TSI with estimated changes since the Maunder minimum ranging from 0.7 Wm À2 to 6 Wm À2 (Wang et al, 2005;Krivova et al, 2007Krivova et al, , 2010Tapping et al, 2007;Steinhilber et al, 2009;Shapiro et al, 2011;Vieira et al, 2011;Judge et al, 2012Judge et al, , 2020Egorova et al, 2018;Wu et al, 2018;Lockwood & Ball, 2020). The various SI models also estimate different SSI variations on timescales longer than a few solar rotations (see Ermolli et al, 2013, for a review of this topic).…”

Section: Introductionmentioning

confidence: 99%

Modelling solar irradiance from ground-based photometric observations

Chatzistergos

Ermolli

Giorgi

et al. 2020

J. Space Weather Space Clim.

View full text Add to dashboard Cite

Total solar irradiance (TSI) has been monitored from space since 1978, i.e. for about four solar cycles. The measurements show a prominent variability in phase with the solar cycle, as well as fluctuations on timescales shorter than a few days. However, the measurements were done by multiple and usually relatively short-lived missions. The different absolute calibrations of the individual instruments and the unaccounted for instrumental trends make estimates of the possible long-term trend in the TSI highly uncertain. Furthermore, both the variability and the uncertainty are strongly wavelength-dependent. While the variability in the UV irradiance is clearly in-phase with the solar cycle, the phase of the variability in the visible range has been debated. In this paper, we aim at getting an insight into the long-term trend of TSI since 1996 and the phase of the solar irradiance variations in the visible part of the spectrum. We use independent ground-based full-disc photometric observations in Ca II K and continuum from the Rome and San Fernando observatories to compute the TSI since 1996. We follow the empirical San Fernando approach based on the photometric sum index. We find a weak declining trend in the TSI of $ {-7.8}_{-0.8}^{+4.9}\times 1{0}^{-3}$ Wm−2 y−1 between the 1996 and 2008 activity minima, while between 2008 and 2019 the reconstructed TSI shows no trend to a marginally decreasing (but statistically insignificant) trend of $ {-0.1}_{-0.02}^{+0.25}\times 1{0}^{-3}$ Wm−2 y−1. The reference TSI series used for the reconstruction does not significantly affect the determined trend. The variation in the blue continuum (409.2 nm) is rather flat, while the variation in the red continuum (607.1 nm) is marginally in anti-phase, although this result is extremely sensitive to the accurate assessment of the quiet Sun level in the images. These results provide further insights into the long-term variation of the TSI. The amplitude of the variations in the visible is below the uncertainties of the processing, which prevents an assessment of the phase of the variations.

show abstract

A Discussion of Implausible Total Solar-Irradiance Variations Since 1700

Chatzistergos

2024

Sol Phys

View full text Add to dashboard Cite

The Sun plays a role in influencing Earth’s climate, making it important to have accurate information about variations in the Sun’s radiative output. Models are used to recover total solar-irradiance (TSI) variations in the past when direct space-based measurements are not available. One of the most cryptic such TSI reconstructions is the one by (J. Geophys. Res. 98, 18, 1993, HS93). The rather vague description of the model methodology, the arbitrary selection of solar indices it employs, and the short overlap between the HS93 series and directly measured TSI values has hindered any evaluation of the performance of this model to this day. Here, we aim at rectifying this by updating the HS93 model with new input data. In this way we are also contributing in the discussion on the possible long-term changes in solar irradiance.We find that the analysis by HS93 included a number of erroneous processing steps that led to an artificial increasing trend towards the end of the reconstructed TSI series as well as shifting the peak of the TSI in the mid-twentieth century back in time by about 11 years. Furthermore, by using direct measurements of the TSI we determined that the free parameter of the model, the magnitude of variations (here defined as percentage variations of the difference between the maximum to minimum values), is optimal when it is minimised (being ≤0.05%). This is in stark contrast to the high magnitude of variations, of 0.25%, that was imposed by HS93. However, our result is consistent with more recent estimates, such as those from the Spectral And Total Irradiance REconstruction (SATIRE) model and Naval Research Laboratory TSI (NRLTSI), which were used by the Intergovernmental Panel on Climate Change (IPCC). Overall, we find that the previously reported agreement of the HS93 TSI series to temperature on Earth was purely due to improper analysis and artefacts of the processing.

show abstract

Placing limits on long-term variations in quiet-Sun irradiance and their contribution to total solar irradiance and solar radiative forcing of climate

Cited by 22 publications

References 63 publications

The Dimmest State of the Sun

The Dimmest State of the Sun

Modelling solar irradiance from ground-based photometric observations

A Discussion of Implausible Total Solar-Irradiance Variations Since 1700

Contact Info

Product

Resources

About