SORCE Contributions to New Understanding of Global Change and Solar Variability

Lean, J.; Rottman, G. J.; Harder, J. W.; Kopp, Greg

doi:10.1007/s11207-005-1527-2

Cited by 294 publications

(254 citation statements)

References 78 publications

Supporting

Mentioning

248

Contrasting

Order By: Relevance

“…However, the strengthening or weakening of the BDC is still under debate (Butchart, 2014, and references therein). Results from observations indicate that the BDC may have slightly decelerated (Engel et al, 2009;Stiller et al, 2012), while estimates from a number of chemistry-climate models (CCMs) show in contrast a strengthening of the BDC (Butchart et al, 2010;Li et al, 2008;Butchart, 2014). The reason for the discrepancy between observed and modelled BDC changes, as well as the mechanisms of the BDC response to climate change, is still under discussion (Oberländer et al, 2013;Shepherd and McLandress, 2011).…”

Section: W Wang Et Al: Contributions To Recent Ttl Variabilitymentioning

confidence: 99%

“…Table 1 gives an overview of all coupled CESM simulations. A control run was performed from 1955 to 2099 (Natural run hereafter) with all natural forcing including spectrally resolved solar variability (Lean et al, 2005) SPARC-CCMVal, 2010) and a nudged QBO. The QBO is nudged by relaxing the modelled tropical zonal winds to observations between 22 • S and N, using a Gaussian weighting function with a half width of 10 • decaying latitudinally from the equator.…”

Section: W Wang Et Al: Contributions To Recent Ttl Variabilitymentioning

confidence: 99%

See 1 more Smart Citation

Quantifying contributions to the recent temperature variability in the tropical tropopause layer

2015

View full text Add to dashboard Cite

Abstract. The recently observed variability in the tropical tropopause layer (TTL), which features a warming of 0.9 K over the past decade (2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011), is investigated with a number of sensitivity experiments from simulations with NCAR's CESM-WACCM chemistry-climate model. The experiments have been designed to specifically quantify the contributions from natural as well as anthropogenic factors, such as solar variability (Solar), sea surface temperatures (SSTs), the quasi-biennial oscillation (QBO), stratospheric aerosols (Aerosol), greenhouse gases (GHGs) and the dependence on the vertical resolution in the model. The results show that, in the TTL from 2001 through 2011, a cooling in tropical SSTs leads to a weakening of tropical upwelling around the tropical tropopause and hence relative downwelling and adiabatic warming of 0.3 K decade −1 ; stronger QBO westerlies result in a 0.2 K decade −1 warming; increasing aerosols in the lower stratosphere lead to a 0.2 K decade −1 warming; a prolonged solar minimum contributes about 0.2 K decade −1 to a cooling; and increased GHGs have no significant influence. Considering all the factors mentioned above, we compute a net 0.5 K decade −1 warming, which is less than the observed 0.9 K decade −1 warming over the past decade in the TTL. Two simulations with different vertical resolution show that, with higher vertical resolution, an extra 0.8 K decade −1 warming can be simulated through the last decade compared with results from the "standard" low vertical resolution simulation. Model results indicate that the recent warming in the TTL is partly caused by stratospheric aerosols and mainly due to internal variability, i.e. the QBO and tropical SSTs. The vertical resolution can also strongly influence the TTL temperature response in addition to variability in the QBO and SSTs.

show abstract

Section: W Wang Et Al: Contributions To Recent Ttl Variabilitymentioning

confidence: 99%

Section: W Wang Et Al: Contributions To Recent Ttl Variabilitymentioning

confidence: 99%

Quantifying contributions to the recent temperature variability in the tropical tropopause layer

2015

View full text Add to dashboard Cite

show abstract

“…In recent years a number of models of solar irradiance variability have been created that are to some extent based on such a concept (e.g. Fligge et al 2000;Krivova et al 2003;Lean et al 2005;Shapiro et al 2011b;Fontenla et al 2011;Bolduc et al 2014;Ball et al 2014;Yeo et al 2014b). …”

Section: Introductionmentioning

confidence: 99%

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

“…Lean et al 2005;Krivova et al 2010;Shapiro et al 2011), give smaller values of the present solar variability for the last 50 years: 0.00027, 0.00017, and 0.00017 mag respectively. We used the mean of these three numbers to locate the Sun in Fig.…”

Section: Comparison Of the Stellar And Present Solar Variabilitymentioning

confidence: 91%

“…The present consensus is that secular changes in solar irradiance are proportional to secular changes in solar activity proxies. However, there is no agreement on the scaling coefficient (Lean et al 2005;Tapping et al 2007;Krivova et al 2010;Schrijver et al 2011;Vieira et al 2011;Shapiro et al 2011;Thuillier et al 2012;Judge et al 2012). To illustrate the effect of the secular variations on the solar photometric variability in Fig.…”

Section: Comparison Of the Stellar And Historical Solar Variabilitymentioning

confidence: 99%

The place of the Sun among the Sun-like stars

Шапиро

Schmutz

Cessateur

et al. 2013

A&A

View full text Add to dashboard Cite

Context. Monitoring of the photometric and chromospheric HK emission data series of stars similar to the Sun in age and average activity level showed that there is an empirical correlation between the average stellar chromospheric activity level and the photometric variability. In general, more active stars show larger photometric variability. Interestingly, the measurements and reconstructions of the solar irradiance show that the Sun is significantly less variable than indicated by the empirical relationship. Aims. We aim to identify possible reasons for the Sun to be currently outside of this relationship. Methods. We employed different scenarios of solar HK emission and irradiance variability and compared them with available time series of Sun-like stars. Results. We show that the position of the Sun on the diagram of photometric variability versus chromospheric activity changes with time. The present solar position is different from its temporal mean position as the satellite era of continuous solar irradiance measurements has accidentally coincided with a period of unusually high and stable solar activity. Our analysis suggests that although present solar variability is significantly smaller than indicated by the stellar data, the temporal mean solar variability might be in agreement with the stellar data. We propose that the continuation of the photometric program and its expansion to a larger stellar sample will ultimately allow us to constrain the historical solar variability.

show abstract

SORCE Contributions to New Understanding of Global Change and Solar Variability

Cited by 294 publications

References 78 publications

Quantifying contributions to the recent temperature variability in the tropical tropopause layer

Quantifying contributions to the recent temperature variability in the tropical tropopause layer

The role of the Fraunhofer lines in solar brightness variability

The place of the Sun among the Sun-like stars

Contact Info

Product

Resources

About