To the description of long-term variations in the solar magnetic flux: The sunspot area index

Nagovitsyn, Yu. A.

doi:10.1134/1.2007032

Cited by 31 publications

(11 citation statements)

References 9 publications

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“…Similar phase transitions took place around 1628 (onset of the Maunder Minimum), in 1740 (end of Maunder Minimum, and transition to a period of Regular Oscillations; our Table 1 (Duhau and de Jager 2008), but these are unverifiable, being based on extrapolated, hence uncertain values of the proxy data of the magnetic fluxes: First, the aa min data are only known after 1844 and earlier aa min data have been derived by Nagovitsyn (2005) by extrapolation. But this extrapolation rests for an important part on the high degree of correlation between R max and aa min , while the essential aspects of the phase diagram are based on the subtle differences between both.…”

Section: The Phase Diagram and The Predictability Of Long-term Solar mentioning

confidence: 99%

A Remarkable Recent Transition in the Solar Dynamo

et al. 2016

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We summarize the major aspects of the remarkable, fairly long lasting period (∼ 2005 to ∼ 2010) of low solar activity, that we will call the Transition. It is the transitional stage between the Grand Maximum of the 20th century and a forthcoming (most probably Regular) episode of solar activity. The various kinds of activity in the functioning of the equatorial components of the solar dynamo before and during the Transition are summarized. While the behavior of unipolar magnetic regions and their rest-latitudes already gave very early indications -mid 20th century -of the forthcoming Transition, more such indications became available around 1995 and the main part of it occurred between 2005 and 2010. Some of the inferences are discussed. We submit the hypothesis that the solar tachocline undergoes pulsations and we present some helioseismic evidences. In that scenario we find that its equatorial part has moved downward over a fairly small semi-amplitude (∼ 0.03 solar radii) during the time of the Transition. There are several indications, apart from this 'pulsation', that the tachocline may even be pulsating with still smaller amplitudes in more modes. We speculate about the physical mechanism(s).

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Section: The Phase Diagram and The Predictability Of Long-term Solar mentioning

confidence: 99%

A Remarkable Recent Transition in the Solar Dynamo

et al. 2016

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“…(1) for the larger time interval . We tried to overcome the difficulty that aa-data are only available from 1844 onward by using the extrapolated aa-data of Nagovitsyn (2005Nagovitsyn ( , 2006Nagovitsyn ( , 2007. The weakness of this approach is that the extrapolation is partly based on sunspot numbers.…”

Section: A Reanalysis Of the Sun-climate Connectionmentioning

confidence: 99%

“…The diagrams, though, have been extended to the period from 1610 to 2008. As written before, observed aa-data do not exist before 1844 and we used the extrapolated aa-values of Nagovitsyn (2005Nagovitsyn ( , 2006Nagovitsyn ( , 2007 for the period 1610-1844, realizing, of course, that these have not the same value as direct observation. We analysed them in a previous investigation (Duhau and De Jager, 2008) and found them reasonably reliable.…”

Section: Analysis Of the Componentsmentioning

confidence: 99%

Quantifying and specifying the solar influence on terrestrial surface temperature

Jager

Duhau

Geel

2010

Journal of Atmospheric and Solar-Terrestrial Physics

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This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. b s t r a c tThis investigation is a follow-up of a paper in which we showed that both major magnetic components of the solar dynamo, viz. the toroidal and the poloidal ones, are correlated with average terrestrial surface temperatures. Here, we quantify, improve and specify that result and search for their causes. We studied seven recent temperature files. They were smoothed in order to eliminate the Schwabe-type (11 years) variations. While the total temperature gradient over the period of investigation (1610-1970) is 0.087 1C/century; a gradient of 0.077 1C/century is correlated with the equatorial (toroidal) magnetic field component. Half of it is explained by the increase of the Total Solar Irradiance over the period of investigation, while the other half is due to feedback by evaporated water vapour. A yet unexplained gradient of À 0.040 1C/century is correlated with the polar (poloidal) magnetic field. The residual temperature increase over that period, not correlated with solar variability, is 0.051 1C/century. It is ascribed to climatologic forcings and internal modes of variation.We used these results to study present terrestrial surface warming. By subtracting the above-mentioned components from the observed temperatures we found a residual excess of 0.311 in 1999, this being the triangularly weighted residual over the period 1990-2008. We show that solar forcing of the ground temperature associated with significant feedback is a regularly occurring feature, by describing some well observed events during the Holocene.

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“…This variable gives a measure of the strength of the toroidal component of the solar magnetic field [16]. As solar activity ultimately depends on solar magnetic field strength [17][18][19][20][21] all the variables related to solar activity must bear some relationship with sunspot number.…”

Section: Introductionmentioning

confidence: 99%

Solar Dynamo Transitions as Drivers of Sudden Climate Changes

Duhau¹

2012

Global Warming - Impacts and Future Perspectives

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To the description of long-term variations in the solar magnetic flux: The sunspot area index

Cited by 31 publications

References 9 publications

A Remarkable Recent Transition in the Solar Dynamo

A Remarkable Recent Transition in the Solar Dynamo

Quantifying and specifying the solar influence on terrestrial surface temperature

Solar Dynamo Transitions as Drivers of Sudden Climate Changes

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