Solar UV variations during the decline of Cycle 23

DeLand, Matthew T.; Cebula, R. P.

doi:10.1016/j.jastp.2012.01.007

Cited by 64 publications

(76 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…8). Note that good agreement on rotational timescales was also found by DeLand and Cebula (2012) between SORCE and other spectral observations.…”

Section: Discussion Of Ssi Model Resultssupporting

confidence: 82%

“…This situation changed with the launch of the Spectral Irradiance Monitor instrument (SIM, Harder et al, 2005a) onboard the Solar Radiation and Climate Experiment satellite (SORCE, Rottman, 2005) in 2003, which was shortly after the most recent maximum of solar activity. The SORCE/SIM data showed a 4-6 times greater decrease of the UV radiation between 200 and 400 nm over the period , part of the declining phase of solar cycle 23, compared to earlier measurements and models (Ball et al, 2011;Pagaran et al, 2011a;Unruh et al, 2012;DeLand and Cebula, 2012;Lean and DeLand, 2012). This larger decrease measured in the UV (Fig.…”

Section: Introductionmentioning

confidence: 46%

“…the "bottom-up" mechanism, van Loon et al, 2007;Meehl et al, 2009). Early satellite measurements of the solar UV variability have shown a qualitatively consistent behaviour (DeLand and Cebula, 2012), which is fairly well reproduced by SSI models (e.g. Lean et al, 1997;Krivova et al, 2006;Unruh et al, 2012;Lean and DeLand, 2012).…”

Section: Introductionmentioning

confidence: 90%

“…In addition to SOLSTICE and SUSIM, there is the long time series of 200-400 nm solar UV observations by several NOAA SBUV (Solar Backscatter Ultraviolet) instruments, which had underflight calibrations aboard the Space Shuttle . Table 1 of DeLand and Cebula (2012) summarises the measurement uncertainties for these instruments. Regular observations of the visible and NIR bands covering more than one year started with SOHO/VIRGO-SPM (SOlar and Heliospheric Observatory/Variability of IRradiance and Gravity Oscillations Sun PhotoMeter) in 1996 at three selected bands and continued with the ERS/GOME (European Remote Sensing/Global Ozone Monitoring Experiment) (Weber et al, 1998;Burrows et al, 1999), ENVISAT/SCIAMACHY (Bovensmann et al, 1999), SORCE/SIM (Harder et al, 2005a,b), and ISS/SOLSPEC (International Space Station/SOLar SPECtrum) instruments.…”

Section: Observation Of Solar Irradiancementioning

confidence: 99%

See 3 more Smart Citations

Recent variability of the solar spectral irradiance and its impact on climate modelling

et al. 2013

View full text Add to dashboard Cite

The lack of long and reliable time series of solar spectral irradiance (SSI) measurements makes an accurate quantification of solar contributions to recent climate change difficult. Whereas earlier SSI observations and models provided a qualitatively consistent picture of the SSI variability, recent measurements by the SORCE (SOlar Radiation and Climate Experiment) satellite suggest a significantly stronger variability in the ultraviolet (UV) spectral range and changes in the visible and near-infrared (NIR) bands in anti-phase with the solar cycle. A number of recent chemistry-climate model (CCM) simulations have shown that this might have significant implications on the Earth's atmosphere. Motivated by these results, we summarize here our current knowledge of SSI variability and its impact on Earth's climate.

We present a detailed overview of existing SSI measurements and provide thorough comparison of models available to date. SSI changes influence the Earth's atmosphere, both directly, through changes in shortwave (SW) heating and therefore, temperature and ozone distributions in the stratosphere, and indirectly, through dynamical feedbacks. We investigate these direct and indirect effects using several state-of-the art CCM simulations forced with measured and modelled SSI changes. A unique asset of this study is the use of a common comprehensive approach for an issue that is usually addressed separately by different communities.

We show that the SORCE measurements are difficult to reconcile with earlier observations and with SSI models. Of the five SSI models discussed here, specifically NRLSSI (Naval Research Laboratory Solar Spectral Irradiance), SATIRE-S (Spectral And Total Irradiance REconstructions for the Satellite era), COSI (COde for Solar Irradiance), SRPM (Solar Radiation Physical Modelling), and OAR (Osservatorio Astronomico di Roma), only one shows a behaviour of the UV and visible irradiance qualitatively resembling that of the recent SORCE measurements. However, the integral of the SSI computed with this model over the entire spectral range does not reproduce the measured cyclical changes of the total solar irradiance, which is an essential requisite for realistic evaluations of solar effects on the Earth's climate in CCMs.

We show that within the range provided by the recent SSI observations and semi-empirical models discussed here, the NRLSSI model and SORCE observations represent the lower and upper limits in the magnitude of the SSI solar cycle variation.

The results of the CCM simulations, forced with the SSI solar cycle variations estimated from the NRLSSI model and from SORCE measurements, show that the direct solar response in the stratosphere is larger for the SORCE than for the NRLSSI data. Correspondingly, larger UV forcing also leads to a larger surface response.

Finally, we discuss the reliability of the available data and we propose additional coordinated work, first to build composite SSI data sets out of scattered observations and to r...

show abstract

“…8). Note that good agreement on rotational timescales was also found by DeLand and Cebula (2012) between SORCE and other spectral observations.…”

Section: Discussion Of Ssi Model Resultssupporting

confidence: 82%

Section: Introductionmentioning

confidence: 46%

Section: Introductionmentioning

confidence: 90%

Section: Observation Of Solar Irradiancementioning

confidence: 99%

See 2 more Smart Citations

Recent variability of the solar spectral irradiance and its impact on climate modelling

et al. 2013

View full text Add to dashboard Cite

show abstract

“…Measurements of the spectral solar irradiance (SSI, which is the solar radiative flux per unit wavelength at one au from the Sun) showed the variability on the same two timescales (see Floyd et al 2003;Harder et al 2009;Deland & Cebula 2012, and references therein). They also indicated that the amplitude of the relative SSI variations strongly depends on the wavelength and generally increases towards short wavelengths.…”

Section: Introductionmentioning

confidence: 98%

The role of the Fraunhofer lines in solar brightness variability

Шапиро

Solanki

Krivova

et al. 2015

A&A

View full text Add to dashboard Cite

Context. The solar brightness varies on timescales from minutes to decades. A clear identification of the physical processes behind such variations is needed for developing and improving physics-based models of solar brightness variability and reconstructing solar brightness in the past. This is, in turn, important for better understanding the solar-terrestrial and solar-stellar connections. Aims. We estimate the relative contributions of the continuum, molecular, and atomic lines to the solar brightness variations on different timescales. Methods. Our approach is based on the assumption that variability of the solar brightness on timescales greater than a day is driven by the evolution of the solar surface magnetic field. We calculated the solar brightness variations employing the solar disc area coverage of magnetic features deduced from the MDI/SOHO observations. The brightness contrasts of magnetic features relative to the quiet Sun were calculated with a non-LTE radiative transfer code as functions of disc position and wavelength. By consecutive elimination of molecular and atomic lines from the radiative transfer calculations, we assessed the role of these lines in producing solar brightness variability. Results. We show that the variations in Fraunhofer lines define the amplitude of the solar brightness variability on timescales greater than a day and even the phase of the total solar irradiance variability over the 11-year cycle. We also demonstrate that molecular lines make substantial contribution to solar brightness variability on the 11-year activity cycle and centennial timescales. In particular, our model indicates that roughly a quarter of the total solar irradiance variability over the 11-year cycle originates in molecular lines. The maximum of the absolute spectral brightness variability on timescales greater than a day is associated with the CN violet system between 380 and 390 nm.

show abstract

Suprathermal magnetospheric minor ions heavier than water at Saturn: Discovery of ²⁸M⁺ seasonal variations

et al. 2014

View full text Add to dashboard Cite

Solar UV variations during the decline of Cycle 23

Cited by 64 publications

References 46 publications

Recent variability of the solar spectral irradiance and its impact on climate modelling

Recent variability of the solar spectral irradiance and its impact on climate modelling

The role of the Fraunhofer lines in solar brightness variability

Suprathermal magnetospheric minor ions heavier than water at Saturn: Discovery of ²⁸M⁺ seasonal variations

Contact Info

Product

Resources

About

Solar UV variations during the decline of Cycle 23

Cited by 64 publications

References 46 publications

Recent variability of the solar spectral irradiance and its impact on climate modelling

Recent variability of the solar spectral irradiance and its impact on climate modelling

The role of the Fraunhofer lines in solar brightness variability

Suprathermal magnetospheric minor ions heavier than water at Saturn: Discovery of 28M+ seasonal variations

Contact Info

Product

Resources

About

Suprathermal magnetospheric minor ions heavier than water at Saturn: Discovery of ²⁸M⁺ seasonal variations