Common oscillatory modes in geomagnetic activity, NAO index and surface air temperature records

Paluš, Milan; Novotná, Dagmar

doi:10.1016/j.jastp.2007.05.009

Cited by 17 publications

(8 citation statements)

References 50 publications

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“…Notably, the relationships among the winter O(8) modes of SLH, SAT and D illustrated in Figure 11, and specifically the phase‐switches in the 1920s and 1950s, may therefore reflect climatic features that have a solar origin. In fact, the 7.8‐year periodicity associated with the fundamental O(8) mode, which is detected both on the NAO and on descriptors of the north Italian regional climate (SLH, D and SAT), characterizes also the variability of the geomagnetic aa index (GIAA) [ Paluš and Novotná , 2007; P1]. Researches attempting to individuate a link between the GIAA and large‐scale atmospheric variability have a long and checkered history.…”

Section: A Solar Connection?mentioning

confidence: 99%

“…On the other hand, the alternation of peculiar periods of phase‐locked and phase‐drifting fluctuations in the NAO and in Venetian SLH during and after the preindustrial period may add circumstantial emphasis to the working hypothesis that we recently outlined [ Zanchettin et al , 2008a] (hereafter P1) by documenting an apparent modulation of the North Italian hydrological decadal patterns by means of solar activity during the last 2 centuries. We also outlined how solar‐induced changes in the state of the NAO via interactions with the solar wind driven by the Sun's inertial motion [ Landscheidt , 1999] and with the outer geomagnetic field controlled by sunspot activity [ Paluš and Novotná , 2007] could represent a key factor for addressing a consistent linkage over 100‐year (or larger) periods between solar forcing and the North Italian regional climate. Formerly, Palumbo and Mazzarella [1985] have shown how astronomical forcing represents a primary source of SLH variability in the multidecadal band; more recently, Tomasin [2005] has observed a robust correlation since 1940 between the duration of high surge anomalies in the Lagoon of Venice and the strength of sunspot activity.…”

Section: Introductionmentioning

confidence: 99%

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Teleconnections force interannual‐to‐decadal tidal variability in the Lagoon of Venice (northern Adriatic)

et al. 2009

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[1] In the present investigation, for the first time, fundamental characteristics of autumn and winter average sequences of sea level heights (SLH) that were recorded in the Lagoon of Venice (northern Adriatic, in the Mediterranean Sea) during the period 1872-2004 are investigated. Interannual-to-decadal variability of Venetian SLH is found to reflect the variability of the most prominent Euro-Atlantic teleconnections (EATs). In particular, the North Atlantic Oscillation (NAO), the East Atlantic/Western Russian, and the Scandinavian patterns are found to contribute to generate the $5-year, $8-year and $22-year peaks that dominate the spectra of seasonal Venetian SLH. Among the possible oceanic and atmospheric phenomena downscaling interannual-to-decadal large-scale atmospheric signals into the observed variability in the Venetian SLH, we explore inverse barometer effect, wind-driven setup, and the thermohaline circulation of both the Adriatic and the Mediterranean seas. All these phenomena are assessed to display some of the typical features of the shared interannual-to-decadal variability of both Venetian SLH and EATs. Our analysis shows also that the decadal variability of winter Venetian SLH is closely linked with variations in solar activity: in particular, the winter SLH multidecadal pattern is found to be correlated, with very high statistical confidence, to the Hale Cycles pattern ($22 years), which describes the series of sunspot cycles with alternating opposite polarity. The marked signature of Hale Cycles on the leading mode of multidecadal sea level pressure winter variability (which is practically indistinguishable from the inverse wintertime NAO) is also detailed to further support the hypothesis of a Sun-Venetian SLH association.

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Section: A Solar Connection?mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Teleconnections force interannual‐to‐decadal tidal variability in the Lagoon of Venice (northern Adriatic)

et al. 2009

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“…They showed that stratospheric wind and temperature variations are positively projected onto the NAM when the 11 year SC is at its maximum phase during winter, and negatively projected onto the NAM during the 11 year SC minimum phase in spring. Paluš and Novotná [2007] found that there were common oscillatory modes in the geomagnetic aa index, the NAO and surface temperature. It has been also suggested that solar wind induced geomagnetic activity may alter stratospheric chemistry through particle precipitation and descent of odd Nitrogen (NO x ) [ Randall et al , 2005, 2006, 2007; Solomon et al , 1982].…”

Section: Introductionmentioning

confidence: 97%

Nonlinear and nonstationary influences of geomagnetic activity on the winter North Atlantic Oscillation

Li¹,

Lu²,

Jarvis³

et al. 2011

J. Geophys. Res.

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[1] The relationship between the geomagnetic aa index and the winter North Atlantic Oscillation (NAO) has previously been found to be nonstationary, being weakly negative during the early 20th century and significantly positive since the 1970s. The study reported here applies a statistical method called the generalized additive modeling (GAM) to elucidate the underlying physical reasons. We find that the relationship between aa index and the NAO during the Northern Hemispheric winter is generally nonlinear and can be described by a concave shape with a negative relation for small to medium aa and a positive relation for medium to large aa. The nonstationary character of the aa-NAO relationship may be ascribed to two factors. First, it is modulated by the multidecadal variation of solar activity. This solar modulation is indicated by significant change points of the trends of solar indices around the beginning of solar cycle 14, 20, and 22 (i.e., ∼1902/1903, ∼1962/1963, and ∼1995/1996). Coherent changes of the trend in the winter time NAO followed the solar trend changes a few years later. Second, the aa-NAO relationship is dominated by the aa data from the declining phase of even-numbered solar cycles, implying that the 27 day recurrent solar wind streams may be responsible for the observed aa-NAO relationship. It is possible that an increase of long-duration recurrent solar wind streams from high-latitude coronal holes during solar cycles 20 and 22 may partially account for the significant positive aa-NAO relationship during the last 30 years of the 20th century.

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“…The spectral characteristics of NAO and GA data show a common occurrence of a peak at approximately 96 months, i.e., ∼7.8 years [ Paluš and Novotná , 2007]. Specifically, this periodic component dominates the decadal variability of the NAO [e.g., Loewe and Kolowski , 1998; Brunetti , 2003; Jevrejeva et al , 2005].…”

Section: Introductionmentioning

confidence: 99%

Impact of variations in solar activity on hydrological decadal patterns in northern Italy

Zanchettin

Rubino²,

Traverso³

et al. 2008

J. Geophys. Res.

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[1] Using spectral and statistical analyses of discharges and basin average precipitation rates acquired over the Po River since the early 1800s, we investigate the impact of variations in solar activity on hydrological decadal patterns over northern Italy. Wet and dry periods appear to alternate in accordance with polarized sunspot cycles. Intriguingly, a solar signature on Po River discharges is detected to be highly significant since the late 1800s, before the onset of sunspots hyperactivity established by the middle 1900s. In particular, observed hydrological patterns over northern Italy are significantly correlated, under periods of quiet sunspot activity, with parameters characterizing the Sun's orbital motion, specifically with the time derivative of the solar angular momentum (t) which is thought to modulate the strength of the solar wind and sunspot dynamics under weak sunspot activity. The North Atlantic Oscillation (NAO) is detected as potential link between the Sun and Po River discharges, since it is significantly correlated with both solar activity and the decadal variability in the north Italian climate. In particular, positive (negative) NAO anomalies, which are associated with comparatively lower (higher) Po River discharges, are assessed to alternatively correlate at decadal timescales either with t or with the Earth's geomagnetic activity (GA), which closely follows sunspot activity. This changing correlation seems to be regulated by the strength of sunspot activity: under periods of quiet sunspot activity, a weakening of the GA-NAO connection and a reinforcement of the t-NAO connection is observed. In this sense, the strength of solar activity apparently modulates the connection between the NAO and Po River discharges.

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Common oscillatory modes in geomagnetic activity, NAO index and surface air temperature records

Cited by 17 publications

References 50 publications

Teleconnections force interannual‐to‐decadal tidal variability in the Lagoon of Venice (northern Adriatic)

Teleconnections force interannual‐to‐decadal tidal variability in the Lagoon of Venice (northern Adriatic)

Nonlinear and nonstationary influences of geomagnetic activity on the winter North Atlantic Oscillation

Impact of variations in solar activity on hydrological decadal patterns in northern Italy

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