Long-term correlation between solar and geomagnetic activity

Echer, E.; González, W. D.; González, Alicia; Prestes, A.; Vieira, L. E. A.; Lago, A. Dal; Guarnieri, F. L.; Schuch, Nelson Jorge

doi:10.1016/j.jastp.2004.03.011

Cited by 77 publications

(84 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Mayaud, 1980;Rangarajan, 1989). Among those that are most frequently used are the "local" K index, which measures the range of magnetic-field variation at an individual observatory over 3-h periods of time, and the "planetary" aa index, which is derived from a weighted average of K-index values from two nearly-antipodal, mid-latitude observatories, (Delouis and Mayaud, 1975;Clilverd et al, 1998;Echer et al, 2004), (2) space-weather hazards (Oler, 2004;Welling, 2010), (3) solar-terrestrial interaction (Schatten and Wilcox, 1967;Feynman and Crooker, 1978;Lockwood et al, 1999), (4) solar activity and space-weather prediction (Feynman and Gu, 1986;Rangarajan and Barreto, 1999;Hathaway, 2010), (5) terrestrial climate change (Bucha and Bucha, 1998;Friis-Christensen, 2000;Courtillot et al, 2007), (6) atmospheric ozone depletion (Laštovička et al, 1992), and (7) cosmic rays and atmospheric radionuclide production (Stuiver and Quay, 1980;McCracken, 2004). But the fidelity of the aa time series has been the subject of a debate played out in the scientific literature.…”

Section: Introductionmentioning

confidence: 99%

Secular trends in storm-level geomagnetic activity

Love

2011

Ann. Geophys.

View full text Add to dashboard Cite

Abstract. Analysis is made of K-index data from groups of ground-based geomagnetic observatories in Germany, Britain, and Australia, 1868.0-2009.0, solar cycles 11-23. Methods include nonparametric measures of trends and statistical significance used by the hydrological and climatological research communities. Among the three observatory groups, German K data systematically record the highest disturbance levels, followed by the British and, then, the Australian data. Signals consistently seen in K data from all three observatory groups can be reasonably interpreted as physically meaninginful: (1) geomagnetic activity has generally increased over the past 141 years. However, the detailed secular evolution of geomagnetic activity is not well characterized by either a linear trend nor, even, a monotonic trend. Therefore, simple, phenomenological extrapolations of past trends in solar and geomagnetic activity levels are unlikely to be useful for making quantitative predictions of future trends lasting longer than a solar cycle or so. (2) The well-known tendency for magnetic storms to occur during the declining phase of a sunspot-solar cycles is clearly seen for cycles 14-23; it is not, however, clearly seen for cycles 11-13. Therefore, in addition to an increase in geomagnetic activity, the nature of solar-terrestrial interaction has also apparently changed over the past 141 years.

show abstract

Section: Introductionmentioning

confidence: 99%

Secular trends in storm-level geomagnetic activity

Love

2011

Ann. Geophys.

View full text Add to dashboard Cite

show abstract

“…The long term geomagnetic data series, and in particular the aa indices (Mayaud, 1968(Mayaud, , 1980Menvielle and Berthelier, 1991) provide continuous information on geomagnetic activity from 1868 onwards, and they are used in a variety of applications ranging from long-term solar and solar wind variability to climate change (e.g., Feynman and Crooker, 1978;Cliver et al, 1998a, b;Lockwood et al, 1999;Solanki et al, 2000;Echer et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

On the long term change in the geomagnetic activity during the 20th century

et al. 2009

View full text Add to dashboard Cite

Abstract. The analysis of the aa index series presented in this paper clearly shows that during the last century (1900 to 2000) the number of quiet days (Aa<20 nT) drastically diminished from a mean annual value greater than 270 days per year at the end of the nineteenth century to a mean value of 160 quiet days per year one hundred years later. This decrease is mainly due to the decrease of the number of very quiet days (Aa<13 nT). We show that the so-evidenced decrease in the number of quiet days cannot be accounted for by drift in the aa baseline resulting in a systematic underestimation of aa during the first quarter of the century: a 2-3 nT overestimation in the aa increase during the 20th century would lead to a 20-40% overestimation in the decrease of the number of quiet days during the same period.The quiet days and very quiet days correspond to periods during which the Earth encounters slow solar wind streams flowing in the heliosheet during the period where the solar magnetic field has a dipolar geometry. Therefore, the observed change in the number of quiet days is the signature of a long term evolution of the solar coronal field topology. It may be interpreted in terms of an increase in the magnitude of the solar dipole, the associated decrease of the heliosheet thickness accounting for the observed decrease in the number of quiet days.

show abstract

“…It has been found that the geomagnetic and solar activity correlation has decreased since the end of the 19th century, and the lag between them has increased. The variations of Rz and aa were in phase in the early period (solar cycles [11][12][13][14], and became out of phase in later periods (with a lag of 2 years in solar cycle 22) [4].…”

Section: Introductionmentioning

confidence: 95%

“…A long term correlation study between solar and geomagnetic activity has been reported, using annual averages of the aa index and of the sunspot number Rz as well as Dst and AE geomagnetic indices and solar wind speed data are used for more recent periods, during 1868-2000 [4]. It has been found that the geomagnetic and solar activity correlation has decreased since the end of the 19th century, and the lag between them has increased.…”

Section: Introductionmentioning

confidence: 99%

Long term evolution of geomagnetic activity under the influence of 11 year cyclic variations in solar activity during solar cycle 23 and 24

Waheed¹,

Khan²,

Tripathi³

et al. 2015

IJIRSET

View full text Add to dashboard Cite

ABSTRACT:The solar activity follows an eleven year cyclic variability. The long term changes in the solar activity have a direct impact on the geomagnetic activity. In the present study, we have investigated the geomagnetic response of solar activity. To describe the long term variations of the solar activity we have selected two solar activity indices namely Sunspot Number (Rz) and solar radio flux (F10.7). Similarly to describe the level of geomagnetic activity we have taken four geomagnetic indices namely Dst, Kp, Aa and Ap. The study is carried out for the solar cycle 23 and minimum of solar cycle 24. From our study we found that long term changes in the geomagnetic activity follow a synchronous variation with the corresponding changes in the solar activity. We performed correlation analysis between solar activity and geomagnetic activity indices to access the magnitude of association between them. From correlation analysis we found that both the solar activity indices exhibit a strong correlation with all the four geomagnetic indices. The correlation coefficients of Rz with Dst, Kp, Aa and Ap are 0.78, 0.83, 0.81 and 0.86 respectively while those of F10.7 index with the same indices in the same order are 0.77, 0.83, 0.81 and 0.88.

show abstract

Long-term correlation between solar and geomagnetic activity

Cited by 77 publications

References 27 publications

Secular trends in storm-level geomagnetic activity

Secular trends in storm-level geomagnetic activity

On the long term change in the geomagnetic activity during the 20th century

Long term evolution of geomagnetic activity under the influence of 11 year cyclic variations in solar activity during solar cycle 23 and 24

Contact Info

Product

Resources

About