Stellar Analogs of Solar Activity: The Sun in A Stellar Context

Giampapa, M. S.

doi:10.1007/3-540-27510-x_3

Cited by 12 publications

(5 citation statements)

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“…In the case of solar-like stars, magnetic flux is generated mainly at the tachocline, rather than in the overlying convection zone (see the discussion in Giampapa, 2004). The magnetic flux reservoir in the convection zone receives new magnetic flux rising from the tachocline and loses it through emergence above the photosphere and possibly through reconnection.…”

Section: Discussionmentioning

confidence: 98%

Solar Magnetic Activity and Total Irradiance Since the Maunder Minimum

et al. 2007

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We develop a model for estimating solar total irradiance since 1600 AD using the sunspot number record as input, since this is the only intrinsic record of solar activity extending back far enough in time. Sunspot number is strongly correlated, albeit nonlinearly with the 10.7-cm radio flux (F 10.7 ), which forms a continuous record back to 1947. This enables the nonlinear relationship to be estimated with usable accuracy and shows that relationship to be consistent over multiple solar activity cycles. From the sunspot number record we estimate F 10.7 values back to 1600 AD. F 10.7 is linearly correlated with the total amount of magnetic flux in active regions, and we use it as input to a simple cascade model for the other magnetic flux components. The irradiance record is estimated by using these magnetic flux components plus a very rudimentary model for the modulation of energy flow 310 K.F. Tapping et al. to the photosphere by the subphotospheric magnetic flux reservoir feeding the photospheric magnetic structures. Including a Monte Carlo analysis of the consequences of measurement and fitting errors, the model indicates the mean irradiance during the Maunder Minimum was about 1 ± 0.4 W m −2 lower than the mean irradiance over the last solar activity cycle.

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Section: Discussionmentioning

confidence: 98%

Solar Magnetic Activity and Total Irradiance Since the Maunder Minimum

et al. 2007

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“…Our best estimates of DS, the change in the average TSI between the Maunder Minimum and recent decades, have decreased over recent years (see review by Gray et al 2010). Initially, DS was estimated from surveys of ''Sun-like'' stars (Baliunas and Jastrow 1990;Zhang et al 1994), but results of more extensive surveys did not confirm the key result, nor did they support its application to our Sun (Hall and Lockwood 2004;Giampapa 2004). Subsequently, smaller DS estimates have been derived using sunspot numbers and the open magnetic flux of the Sun, which can be derived from historic geomagnetic data (see review by .…”

Section: Global Climate Responsementioning

confidence: 95%

“…The balance between these two competing effects is dependent on the cloud altitude: For low clouds the albedo effect dominates (such that more cloud is a cooling effect), whereas for high-altitude clouds the greenhouse trapping effect dominates (so that more cloud gives warming). A great many papers have been written about low-altitude global cloud cover arguing that it shows a solar-cycle variation, consistent with GCR modulation of the growth of cloud condensation nuclei (CCN) (Svensmark and Friis-Christensen 1997;Svensmark 2007;Marsh and Svensmark 2000, 2004. These studies have been based on the available satellite data after 1983, which give global coverage, and so still cover something less than three solar cycles.…”

Section: Cosmic Ray Modulation Of Cloudsmentioning

confidence: 99%

Solar Influence on Global and Regional Climates

Lockwood

2012

Surv Geophys

152

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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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“…The use of such stellar analogs for estimating the long-term changes in TSI was based on the work of Baliunas and Jastrow [1990], who surveyed observations of Sun-like stars. However, recent surveys have not reproduced their results and suggest that the selection of the original set may have been flawed [Hall and Lockwood, 2004;Giampapa, 2004]. Thus, the extent of the positive drift in TSI between the Maunder Minimum and the present day is uncertain.…”

Section: Century-scale Solar Variabilitymentioning

confidence: 99%

Solar Influences on Climate

et al. 2010

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[1] Understanding the influence of solar variability on the Earth's climate requires knowledge of solar variability, solar-terrestrial interactions, and the mechanisms determining the response of the Earth's climate system. We provide a summary of our current understanding in each of these three areas. Observations and mechanisms for the Sun's variability are described, including solar irradiance variations on both decadal and centennial time scales and their relation to galactic cosmic rays. Corresponding observations of variations of the Earth's climate on associated time scales are described, including variations in ozone, temperatures, winds, clouds, precipitation, and regional modes of variability such as the monsoons and the North Atlantic Oscillation. A discussion of the available solar and climate proxies is provided. Mechanisms proposed to explain these climate observations are described, including the effects of variations in solar irradiance and of charged particles. Finally, the contributions of solar variations to recent observations of global climate change are discussed.

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Stellar Analogs of Solar Activity: The Sun in A Stellar Context

Cited by 12 publications

References 100 publications

Solar Magnetic Activity and Total Irradiance Since the Maunder Minimum

Solar Magnetic Activity and Total Irradiance Since the Maunder Minimum

Solar Influence on Global and Regional Climates

Solar Influences on Climate

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