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Solar activity over the last 1150 years: Does it correlate with climate?

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Abstract

Previous studies of solar influence on climate variations have suffered from the relatively short length of continuous solar observations of less than 400 years. Here we present a reconstructed series of sunspot numbers to study this question over a considerably longer time interval of 1150 years. Comparison of these solar data sets with the Earth's hemispheric and global mean surface temperature series reveals very similar trends. In particular, the solar series also show a 'hockey-stick' shape. The long-term trends in solar data and in northern hemisphere temperatures have a correlation coefficient of about 0.7 - 0.8 at a 94% - 98% confidence level. The full data series correlate at a similar significance level, with the bulk of the correlation being due to the similarity in trends. The last 30 years are not considered, however. In this time the climate and solar data diverge strongly from each other.

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... The impact of solar activity and cosmic radiation on the global climate is indisputable ( Hoyt Over the past few centuries of observation, the number of sunspots has increased while the Earth has been warming. It can be concluded that solar activity affects the global climate, causing warming of the planet ( Usoskin et al. 2005). This view is shared by Boryczka et al. (2012), who, based on the synchronicity of multiyear changes in air temperature in Warsaw and Wolf numbers, demonstrated that the Sun's activity is one of the principal causes of climate change. ...
... However, in recent decades, air temperature has increased considerably, whereas solar activity has shown only small changes and, moreover, a downward trend ( Lockwood 2008). Because total solar radiation, ultraviolet radiation, and cosmic ray flux have not shown any significant changing trend in the past thirty years, researchers have concluded that at least the last episode of warming must have a different cause ( Usoskin et al. 2005). On the other hand, Scafetta and West (2006) postulate that global warming has been progressing at a much faster rate since 1975 than could be expected if the Sun were the sole cause. ...
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This article discusses air temperature variability at Mount Śnieżka in the Sudetes from 1881 to 2012. It analyzes the relationship between changing trends in mean annual air temperature (Tavg) and solar activity, expressed by the mean annual Wolf number. The characteristic feature of changes in annual mean extremes (Tmax, Tmin) and Tavg at Mount Śnieżka is an upward trend. The increase of Tmin (0.148 °C/10 years) has been twice as fast as that for Tmax (0.069 °C/10 years). A strong correlation (almost 1.0) was found between the mean annual Wolf number for twenty-two-year cycles of magnetic changes in the Sun and 1988. During the 1989–2012 cycle, there was a strong increase in Tavg and, at the same time, a decrease in the mean annual Wolf number.
... Wanner et al. (2000) are dating the onset of Introduction Glaser, 2008). Following the sunspot numbers after Usoskin et al. (2004), the first flood-rich period exactly 5 coincides with a period of sunspot minima. According to Fig. 4, the t test value shows significant changes with the beginning and the end of Period #1. ...
... According to the first definition of the Spoerer Minimum, another sunspot minimum coincides with a floodrich period (here period #3). According to the sunspot data of Usoskin et al. (2004), the flood frequency maximum of period #3 also corresponds to the low sunspot numbers of the Spoerer Minimum. ...
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This paper describes the flood sensitivity of the Bavarian part of the Alpine Foreland of Germany and addresses different questions concerning climate variability and flood frequencies, from the 14th century until today. The focal point of the paper is the flood frequency of the superordinate spatial unit of the Bavarian Foreland. Based on written historical sources, the flood history of the Alpine Foreland of Germany can be reconstructed back to the 14th century. One major result is the occurrence of "flood-rich" and "flood-poor" episodes in almost cyclical sequences. Flood-rich periods, before the 16th century based on limited available data, were recorded in the periods 1300–1335, 1370–1450, 1470–1525, 1555–1590, 1615–1665, 1730–1780, 1820–1870, and 1910–1955 as well as in a ninth period beginning in 1980. The flood-rich periods are characterized by longer flood duration. Most of the flood-rich and flood-poor periods (in particular the beginning and the end of them) can be connected to changes in natural climate variability. These include changing sunspot numbers (as a measure of solar activity), so-called Little Ice Age type events (LIATEs) as well as changes in the North Atlantic Oscillation (NAO). Climate signals from external forcing factors, which could be used to explain the changing flood frequencies in the Bavarian Alpine Foreland, end in 1930. Relationships within the climate system such as the correlation of flood frequencies with the NAO have changed during the transition from the post Little Ice Age period to the Modern Climate Optimum around 1930. Natural climate variability might have been overlaid by anthropogenic climate change.
... Coughlin and Tung (2004) found an 11-year sun-correlated signal in the lower troposphere. Usoskin et al. (2004bUsoskin et al. ( , 2004c studied the correlation between solar activity and surface temperature over the last 1150 years and found a correlation coefficient of 0.7-0.8 with a significance level ranging between 94% and 98%. De Jager and Usoskin (2006) Fig. 3) shows significant correlation, the correlation coefficient being 0.77 ( + 0.10/ À0.17) with a significance level of 99.8%. ...
... To extend the record of solar activity indirect proxy data can be derived from measurements of the cosmogenic radionuclides 10 Be and 14 C (radiocarbon) in natural archives such as ice cores and tree rings (Beer et al., 1990(Beer et al., , 2006Muscheler et al., 2004;Stuiver et al., 1991;Solanki et al., 2004;Usoskin et al., 2004bUsoskin et al., , 2004cvan Geel, 2008, Steinhilber et al., 2009). Cosmogenic radionuclides are produced continuously in the atmosphere as a result of the interaction of galactic cosmic rays with nitrogen and oxygen. ...
Article
This 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 °C/century; a gradient of 0.077 °C/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 −0.040 °C/century is correlated with the polar (poloidal) magnetic field. The residual temperature increase over that period, not correlated with solar variability, is 0.051 °C/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 0.31° 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.
... Spätestens mit der Auswirkung von FCKW (Fluorchlorkohlenwasserstoffe) auf die Ozonschicht wurde jedoch das Gegenteil bewiesen. Auch Argumente, wie eine wesentlich stärkere Beteiligung an den CO2-Emissionen durch Vulkane ( Hards, 2005;Mörner und Etiope, 2002) oder ein Anstieg der globalen Erwärmung durch eine erhöhte Sonnenaktivität ( Usoskin et al., 2005), konnten widerlegt werden, da keine Zunahme der vulkanischen Aktivität im entsprechenden Zeitraum festgestellt werden kann und die solare Aktivität sogar eine entsprechende Entwicklung leicht kompensieren konnte (klimafakten. de, 2014 20% zum anthropogenen Treibhauseffekt bei. ...
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zur Erlangung des Grades eines Doktors der Naturwissenschaften (Dr. rer. nat.) genehmigte D i s s e r t a t i o n von Kevin Schaper aus Hildesheim Dieses Werk ist copyrightgeschützt und darf in keiner Form vervielfältigt werden noch an Dritte weitergegeben werden. Es gilt nur für den persönlichen Gebrauch.
... While there are studies (see for example, Rind, 1998, 2009;West, 2003, 2005;Scafetta et al., 2004;Scafetta, 2009Scafetta, , 2011Folland et al., 2013;Zhou and Tung, 2013) that find significant relationships between solar radiation and global temperatures, one hand. On the other hand, there are some authors who claim that the two variables are unrelated (see for example, Pittock, 1978Pittock, , 1983Pittock, , 2009Love et al., 2011;Usoskin, et al., 2004). Thus, there is no clear-cut consensus about the possibility of a relationship between solar irradiance and global temperatures (Gil-Alana et al., 2014). ...
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In a recent paper, Gupta et al., (2015), analyzed whether sunspot numbers cause global temperatures based on monthly data covering the period 1880:1-2013:9. The authors find that standard time domain Granger causality test fails to reject the null hypothesis that sunspot numbers does not cause global temperatures for both full and sub-samples, namely 1880:1-1936:2, 1936:3-1986:11 and 1986:12-2013:9 (identified based on tests of structural breaks). However, frequency domain causality test detects predictability for the full-sample at short (2–2.6 months) cycle lengths, but not the sub-samples. But since, full-sample causality cannot be relied upon due to structural breaks, Gupta et al., (2015) concludes that the evidence of causality running from sunspot numbers to global temperatures is weak and inconclusive. Given the importance of the issue of global warming, our current paper aims to revisit this issue of whether sunspot numbers cause global temperatures, using the same data set and sub-samples used by Gupta et al., (2015), based on an nonparametric Singular Spectrum Analysis (SSA)-based causality test. Based on this test, we however, show that sunspot numbers have predictive ability for global temperatures for the three sub-samples, over and above the full-sample. Thus, generally speaking, our non-parametric SSA-based causality test outperformed both time domain and frequency domain causality tests and highlighted that sunspot numbers have always been important in predicting global temperatures.
... This includes authors such as Pittock (1978Pittock ( , 1983Pittock ( , 2009), Love et al. (2011) and others. Usoskin et al. (2005), using a long span of data of about 1150 years, showed that solar activity might be highly correlated with climate. Nevertheless, these authors claim that sunspot numbers cannot explain the warming effect in the temperatures in the last 30 years, whereas they find significant correlation between sunspot number and geomagnetic activity. ...
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This article applies the causality test in the frequency domain, developed by Breitung and Candelon (2006), to analyse whether sunspot numbers (used as a partial approximation to solar irradiance) cause global temperatures, using monthly data covering the time period 1880:1–2013:9. While standard time domain Granger causality test fails to reject the null hypothesis that sunspot numbers do not cause global temperatures for both full and sub-samples (identified based on tests of structural breaks), the frequency domain causality test detects predictability for both the full-sample and the last sub-sample at short (2–2.6 months) and long (10.3 months and above) cycle lengths, respectively. Our results highlight the importance of analysing causality using the frequency domain test, which, unlike the time domain Granger causality test, allows us to decompose causality by different time horizons, and hence, could detect predictability at certain cycle lengths even when the time domain causality test might fail to pick up any causality. Further, given the widespread discussion in the literature, those results for the full-sample causality, irrespective of whether it is in time or frequency domains, cannot be relied upon when there are structural breaks present, and one needs to draw inference regarding causality from the sub-samples, we can conclude that there has been an emergence of causality running from sunspot numbers to global temperatures only recently at cycle length of 10.3 months and above.
... Longer/ bigger rivers mediate and smooth the influence of the factors that alter the climate signals, factors such as local rainfalls, evaporation, topography, lithology, soils, and vegetation (Labat 2008). Usoskin et al. (2005) have shown that sunspot influence on air temperature in the Northern Hemisphere has a 10-year lag, the solar maxima preceding the air temperature increase. Moreover, Huth et al. (2009) have shown that solar activity affects all oscillations in the Northern Hemisphere. ...
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The influence of some climatic oscillations and sunspot number on river flows in Romania, Ukraine, and Moldova is verified by using standard wavelet analyses. The selected climate oscillations are Arctic Oscillation (AO), Antarctic Oscillation (AAO), East Atlantic Oscillation (EAO), East Atlantic/West Russia Oscillation (EAWRO), NINO3.4, North Atlantic Oscillation (NAO), Pacific/North America Oscillation (PNAO), Pacific Decadal Oscillation (PDO), Polar/Eurasia Oscillation (PEO), Scandinavian Oscillation (ScandO), Southern Oscillation (SO), and West Pacific Oscillation (WPO). Forty-five hydrological stations from an area of 45,000 km(2) were used in order to discover the spatial evolution of the periodicities found in rivers. The wavelet analysis is novel for the rivers in the study area. There is an important difference between the periodicities found in mountain and plateau areas and those found in the plain area. There is a general downstream increase in the confidence level of the identified periods, even if the atmospheric precipitation has more relevant periodicities in the mountain area. The periodicities can be grouped into two compact groups: 1-16.5 and 27.8-55.6 years. The correlation matrix of the global wavelet spectrum (GWS) values indicates that NAO, EAWRO, PDO, and the sunspot number are the main factors that generate the periodicities in rivers. It is the first time when the influence of PDO on local rivers is proven. All river periodicities smaller than 16 years have a confidence level of 0.95 or above, as proven by the GWS analysis of the daily discharge data, and are caused by multiple external factors.
... Pittock [14,15] is of the opinion that those authors that obtained significant relationships between sunspot numbers and temperatures such as Scafetta and West [18], Scafetta et al. [19] and West and Grigolini [20] might have produced errors due to data handling and other statistical problems, though similar arguments are claimed by those authors arguing just the contrary. Usoskin et al. [21], using a long span of data of about 1150 years showed that solar activity might be highly correlated with climate. Nevertheless, these authors claim that sunspot numbers cannot explain the warming effect in the temperatures in the last 30 years, whereas they find a significant correlation between sunspot number and geomagnetic activity. ...
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We present an extension of the model of \citet{Solanki:etal:2000} that allows us to reconstruct the time evolution of both the total and the open magnetic flux at the solar surface since 1700. The flux emerging in large active regions is determined using the sunspot number as a proxy, while the flux emergence in small ephemeral regions is described by an extended cycle whose amplitude and length are related to the corresponding sunspot cycle. Both types of regions contribute to the open flux, which is the source of the heliospheric field. The overlap of the activity cycles of ephemeral regions leads to a secular variation of the total cycle-related magnetic flux (active region flux + ephemeral region flux + open flux). The model results indicate that the total surface flux has doubled in the first half of the last century. The evolution of the open flux is in good agreement with the reconstruction by \citet{Lockwood:etal:1999}.
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The extension of the sunspot number series backward in time is of considerable interest for dynamo theory, solar, stellar, and climate research. We have used records of the (10)Be concentration in polar ice to reconstruct the average sunspot activity level for the period between the year 850 to the present. Our method uses physical models for processes connecting the (10)Be concentration with the sunspot number. The reconstruction shows reliably that the period of high solar activity during the last 60 years is unique throughout the past 1150 years. This nearly triples the time interval for which such a statement could be made previously.
  • I G Usoskin
  • S Solanki
  • M Schüssler
  • K Mursula
  • K Alanko
Usoskin, I.G., S. Solanki, M. Schüssler, K. Mursula, and K. Alanko, 2004, Astron. Astrophys., 413, 745
  • P A Stott
  • G S Jones
  • J F B Mitchell
Stott, P.A., G.S. Jones, and J.F.B. Mitchell, 2003, J. of Climate, 16, 4079
  • W Ebisuzaki
Ebisuzaki, W., J. 1997, Clim., 10, 2147
  • J Beer
  • A Blinov
  • G Bonani
  • H J Hofmann
Beer, J., A. Blinov, G. Bonani, H. J. Hofmann, and R. C. Finkel, 1990, Nature, 347, 164
  • G C Reid
Reid, G.C., 2003, Clim. Change, 37, 391
  • E Bard
  • G M Raisbeck
  • F Yiou
  • J Jouzel
Bard, E., G.M. Raisbeck, F. Yiou, and J. Jouzel, 1997, Earth Planet. Sci. Lett., 150, 453
  • D V Hoyt
  • K H Schatten
Hoyt, D.V., and K.H. Schatten, 1993, J. Geoph. Res., 98, 18895
  • D V Hoyt
  • K H Schatten
Hoyt, D.V., and K.H. Schatten, 1998 Solar Phys., 179, 189
  • E Bard
  • G M Raisbeck
  • F Yiou
  • J Jouzel
Bard, E., G. M. Raisbeck, F. Yiou, and J. Jouzel, 2000, Tellus B, 52, 985
  • G Rottman
Rottman, G., 1999, J. Atm. Terr. Phys., 61, 37
  • S K Solanki
  • M Fligge
Solanki, S.K., and M. Fligge, 1998, Geoph. Res. Let., 25, 341
  • J Lean
  • J Beer
  • R Bradley
Lean, J., J. Beer, and R. Bradley, 1995, Geoph. Res. Let., 22, 3195
Solar Variability as an Input to the Earth's Environment
  • N A Krivova
  • S K Solanki
Krivova, N. A., and S. K. Solanki, in A. Wilson (ed.): 2003, Solar Variability as an Input to the Earth's Environment, ESA SP-535, European Space Agency, 275
  • M Fligge
  • S K Solanki
Fligge, M., and S.K. Solanki, 2000, Geoph. Res. Let., 27, 2157