Reconstruction of solar UV irradiance since 1974

Krivova, N. A.; Solanki, S. K.; Wenzler, T.; Podlipnik, B.

doi:10.1029/2009jd012375

Cited by 55 publications

(64 citation statements)

References 47 publications

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“…If confirmed, this is a considerable change in our understanding in spectral irradiance variability as it means that TSI change is predominantly caused by UV changes and that the changes at IR/Visible wavelengths are actually in the opposite direction to those in the UV and TSI. This contrasts sharply with previous models in which the waveform of temporal variations was taken to be similar at all wavelengths (Lean 2000;DeLand and Cebula 2008;Krivova et al 2009). At present, there is no consensus as to how these new results should be used and incorporated into models.…”

Section: Paleoclimate Studies and Solar Proxiescontrasting

confidence: 52%

“…The UV part of the solar spectrum is much more variable than TSI and modulates ozone abundance, temperatures and winds in Earth's stratosphere (see review by Gray et al 2010). Composites of observed UV spectral solar irradiance (SSI) had shown little variation in the spectral shape, such that at all wavelengths they exhibit similar temporal variations to TSI , and this has been reflected in centennial reconstructions of SSI (Lean 2000;Krivova et al 2009). However, recent observations of the descent into the current ''unusual'' (for the space age) solar minimum (Lockwood 2010) cast doubt on this as they show more variability in the UV and considerable change in spectral shape (Harder et al 2009).…”

Section: Paleoclimate Studies and Solar Proxiesmentioning

confidence: 99%

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Solar Influence on Global and Regional Climates

Lockwood

2012

Surv Geophys

149

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The literature relevant to how solar variability influences climate is vast-but much has been based on inadequate statistics and non-robust procedures. The common pitfalls are outlined in this review. The best estimates of the solar influence on the global mean air surface temperature show relatively small effects, compared with the response to anthropogenic changes (and broadly in line with their respective radiative forcings). However, the situation is more interesting when one looks at regional and season variations around the global means. In particular, recent research indicates that winters in Eurasia may have some dependence on the Sun, with more cold winters occurring when the solar activity is low. Advances in modelling ''top-down'' mechanisms, whereby stratospheric changes influence the underlying troposphere, offer promising explanations of the observed phenomena. In contrast, the suggested modulation of low-altitude clouds by galactic cosmic rays provides an increasingly inadequate explanation of observations.

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Section: Paleoclimate Studies and Solar Proxiescontrasting

confidence: 52%

Section: Paleoclimate Studies and Solar Proxiesmentioning

confidence: 99%

Solar Influence on Global and Regional Climates

Lockwood

2012

Surv Geophys

149

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“…In this case, the dispersion is about 0.14 W/m 2 . In order to ensure that not only the total irradiance is reproduced correctly, we also compare the solar irradiance integrated over the wavelength range 220−240 nm (see Krivova et al 2009Krivova et al , 2010b) with the SATIRE-T model output by Krivova et al (2010a).…”

Section: Model Setup and Validationmentioning

confidence: 99%

Evolution of the solar irradiance during the Holocene

Vieira

Solanki

Krivova

et al. 2011

A&A

Self Cite

323

279

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Context. Long-term records of solar radiative output are vital for understanding solar variability and past climate change. Measurements of solar irradiance are available for only the last three decades, which calls for reconstructions of this quantity over longer time scales using suitable models. Aims. We present a physically consistent reconstruction of the total solar irradiance for the Holocene. Methods. We extend the SATIRE (Spectral And Total Irradiance REconstruction) models to estimate the evolution of the total (and partly spectral) solar irradiance over the Holocene. The basic assumption is that the variations of the solar irradiance are due to the evolution of the dark and bright magnetic features on the solar surface. The evolution of the decadally averaged magnetic flux is computed from decadal values of cosmogenic isotope concentrations recorded in natural archives employing a series of physics-based models connecting the processes from the modulation of the cosmic ray flux in the heliosphere to their record in natural archives. We then compute the total solar irradiance (TSI) as a linear combination of the jth and jth + 1 decadal values of the open magnetic flux. In order to evaluate the uncertainties due to the evolution of the Earth's magnetic dipole moment, we employ four reconstructions of the open flux which are based on conceptually different paleomagnetic models. Results. Reconstructions of the TSI over the Holocene, each valid for a different paleomagnetic time series, are presented. Our analysis suggests that major sources of uncertainty in the TSI in this model are the heritage of the uncertainty of the TSI since 1610 reconstructed from sunspot data and the uncertainty of the evolution of the Earth's magnetic dipole moment. The analysis of the distribution functions of the reconstructed irradiance for the last 3000 years, which is the period that the reconstructions overlap, indicates that the estimates based on the virtual axial dipole moment are significantly lower at earlier times than the reconstructions based on the virtual dipole moment. We also present a combined reconstruction, which represents our best estimate of total solar irradiance for any given time during the Holocene. Conclusions. We present the first physics-based reconstruction of the total solar irradiance over the Holocene, which will be of interest for studies of climate change over the last 11 500 years. The reconstruction indicates that the decadally averaged total solar irradiance ranges over approximately 1.5 W/m 2 from grand maxima to grand minima.

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“…Nowadays several datasets for the past spectral solar irradiance (SSI) based on the different reconstruction approaches (e.g. Lean et al 2005;Krivova et al 2009) and satellite measurements are available. However, the remaining disagreements between these data lead to different atmospheric responses when they are used in the climate models (Shapiro et al 2010).…”

Section: Introductionmentioning

confidence: 99%

NLTE solar irradiance modeling with the COSI code

Шапиро¹,

Schmutz²,

Schoell

et al. 2010

A&A

122

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Context. The solar irradiance is known to change on time scales of minutes to decades, and it is suspected that its substantial fluctuations are partially responsible for climate variations. Aims. We are developing a solar atmosphere code that allows the physical modeling of the entire solar spectrum composed of quiet Sun and active regions. This code is a tool for modeling the variability of the solar irradiance and understanding its influence on Earth. Methods. We exploit further development of the radiative transfer code COSI that now incorporates the calculation of molecular lines. We validated COSI under the conditions of local thermodynamic equilibrium (LTE) against the synthetic spectra calculated with the ATLAS code. The synthetic solar spectra were also calculated in non-local thermodynamic equilibrium (NLTE) and compared to the available measured spectra. In doing so we have defined the main problems of the modeling, e.g., the lack of opacity in the UV part of the spectrum and the inconsistency in the calculations of the visible continuum level, and we describe a solution to these problems. Results. The improved version of COSI allows us to reach good agreement between the calculated and observed solar spectra as measured by SOLSTICE and SIM onboard the SORCE satellite and ATLAS 3 mission operated from the Space Shuttle. We find that NLTE effects are very important for the modeling of the solar spectrum even in the visual part of the spectrum and for its variability over the entire solar spectrum. In addition to the strong effect on the UV part of the spectrum, NLTE effects influence the concentration of the negative ion of hydrogen, which results in a significant change of the visible continuum level and the irradiance variability.

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Reconstruction of solar UV irradiance since 1974

Cited by 55 publications

References 47 publications

Solar Influence on Global and Regional Climates

Solar Influence on Global and Regional Climates

Evolution of the solar irradiance during the Holocene

NLTE solar irradiance modeling with the COSI code

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