Long-term trends and Gleissberg cycles in aurora borealis records

Transcription

Solar Physics
DOI: 10.1007/•••••-•••-•••-••••-•
Long-term trends and Gleissberg cycles in aurora
borealis records (1600–2015)
M. Vázquez1,2 · J.M. Vaquero3 ·
M.C. Gallego4 · T. Roca Cortés1,2 ·
P.L. Pallé1,2
c Springer ••••
Abstract The long-term spatial and temporal variation of aurora borealis events
from 1600 to the present were studied using catalogues and other records of
these phenomena. Geographic and geomagnetic coordinates were assigned to
approximately 45 000 auroral events with more than 160 000 observations. They
were analysed separately for three large-scale areas: (i) Europe and North Africa,
(ii) North America, and (iii) Asia. Variations in the cumulative numbers of
auroral events with latitude (in both geographic and geomagnetic coordinates)
were used to discriminate between the two main solar sources: coronal mass
ejections and high-speed streams from coronal holes. We find significant longterm variations in the space-time distribution of auroras. We mainly identify
these with four Gleissberg solar activity cycles whose overall characteristics we
examine. The Asian observations are crucial in this context, and therefore merit
further studies and verifications.
Keywords: Solar activity, Solar cycles, Geomagnetic storm, Aurora borealis
1. Introduction
During the last few decades a network of ground- and space-based instruments
has monitored in detail the interaction (compression and magnetic reconnection)
between the solar wind and the Earth’s magnetosphere (see Saiz et al., 2013).
Especial care has been devoted to the transient events (geomagnetic storms),
that configure the space weather. The process behind these events has three
main phases: (i) the solar sources of energetic particles – flares, coronal mass
1
Instituto de Astrofı́sica de Canarias, 38200 La Laguna,
Spain. email: [email protected]
2 Departamento de Astrofı́sica, Universidad de La Laguna,
38205 La Laguna, Spain.
3 Departamento de Fı́sica, Universidad de Extremadura,
Avda. Santa Teresa de Jornet 38, 06800, Mérida, Spain.
email: [email protected]
4 Departamento de Fı́sica, Universidad de Extremadura,
06071 Badajoz, Spain. email: [email protected]
SOLA: VVGTP2015v8.tex; 6 January 2016; 14:42; p. 1
Vázquez et al.
ejections (CMEs) and coronal holes; (ii) the interplanetary magnetic field (IMF)
configuring the heliosphere; and (iii) the consequences of the impact on the
terrestrial magnetosphere and atmosphere which may give rise to a geomagnetic
solar storm, generally favoured by a southward polarity of the IMF. Close correlations between the three phases have been found (e.g., Tsurutani et al., 1997;
Kamide and Maltsev, 2007; Richardson and Cane, 2012; Lockwood and Owens,
2014). Auroras are a manifestation of this process in the Earth’s atmosphere.
Since they are easily visible without instruments and occupy a large angular
extent of the sky, their occurrence can be tracked over several centuries on the
basis of not only scientific observations but also popular reports. See Chapman
(1970), Siscoe (1980), Silverman (1992), Feldstein et al. (2014), and Akasofu
(2015) for reviews, and the monographs of Eather (1980), Akasofu (2009), and
Vaquero and Vázquez (2009).
Frequency of aurora occurrence can be used as a proxy to study the past behaviour of solar activity. These proxies have a longer coverage than sunspots and
geomagnetic indices, and a better time resolution than provided by cosmogenic
isotopes (14 C, 10 Be). The main disadvantage of using auroras as a proxy of solar
activity is their dependence on the conditions of the IMF and the inhomogenity
of the records, both in space and time. One must also take into account the
warning of Riley et al. (2015) that ”if no aurora was reported, it may or may not
mean that none occurred”. The same applies to sunspots, meaning that these
parameters lead to underestimates of the geomagnetic activity.
The visibility of auroras is limited to ring-shaped regions around the geomagnetic poles – the auroral ovals – centred at around 65 degrees magnetic latitude
in each hemisphere (Feldstein, 1963). Viewed from space, auroras are diffuse
oval rings of light around the geomagnetic poles. Under the impact of a solar
storm, the auroral ovals undergo broadening, particularly on the night side. All
of the great auroral expansions have been associated with intense values of the
interplanetary magnetic field (Sheeley and Howard, 1980). The variation of the
radius of the auroral oval in response to solar wind changes has been studied by
Milan et al. (2009).
Low-latitude auroras are very rare, and are clearly associated with strong
geomagnetic storms produced by solar coronal mass ejections. They are generally
red and diffuse, resulting primarily from an enhancement of the 630.0 nm [O i]
emission due to bombardment by soft electrons (<100 eV) (Tinsley et al., 1986).
The typical altitude for a low-latitude aurora is 250 – 400 km (Roach et al.,
1960; Brekke and Broms, 2013). A similar phenomenon, which shares the same
energy source, is that of stable auroral red arcs, observed mainly during the
recovery phase of geomagnetic storms (Rassoul et al., 1993; Nakazawa, Okada
and Shiokawa, 2004).
In this context, we should also remark that low-latitude auroras have been
observed too during periods of weak to moderate geomagnetic activity. Silverman
(2003), considering US auroral data from 1880 to 1940, has shown that some of
the auroral phenomena occurred under conditions of quiet or moderate magnetic
activity and at low latitudes. He used the term “sporadic aurora” for this type of
auroral phenomenon. As another example, Willis, Stephenson, and Fang (2007)
Aurora Borealis
compiled 42 Chinese and Japanese auroral observations during the period 1840 –
1911, and found that at least 29 of the 42 observations (i.e., 69%) occurred at
times of weak to moderate geomagnetic activity. See also Vaquero, Trigo and
Gallego (2007) and Vaquero, Gallego and Dominguez-Castro (2013) for records
from the Iberian Peninsula and Mexico, respectively.
The visual sensitivity thresholds of the green and red radiation of the auroras
are between one and ten kilorayleighs, which means that only those auroras coming from moderate and strong geomagnetic storms will be visible and therefore
come to form part of our sample (Schröder, Shefov, and Treder, 2004). It is clear
that the meteorological conditions also play a role, although a cloud-free sky is
not necessary.
Fritz (1873) produced the first graph showing the geographical distribution
of auroral frequencies, measured in nights per year. The values ranged from
a minimum in the Mediterranean area to a maximum at a magnetic latitude
of 67 degrees. According to Livesey (1991), the zone with the greatest aurora
borealis probability passes across northern Norway, over to Iceland, south of
Greenland, and over to the south of Hudson Bay in North America. In previous articles (Vázquez, Vaquero and Curto, 2006; Vázquez and Vaquero, 2010;
Vázquez, Vaquero and Gallego, 2014), we started with studies of low-latitude
events available in the Spanish documentary sources. In Vázquez, Vaquero and
Gallego (2014), we began on the task of constructing a global catalogue showing
the results for the period 1705 – 1905. We applied a method to discriminate
between the solar sources of the auroras based on the variation with latitude.
Low- and mid-latitude auroras are well correlated with the solar cycle, indicating
a CME source. On the contrary, high-latitude auroras are anticorrelated with the
11-yr cycle, pointing to a source in the high-speed streams coming from coronal
holes. The critical geomagnetic latitude separating these two sources was found
to be located at around 61 degrees.
In the present communication, our intention is to update this catalogue and
to extend the coverage to the period 1600 – 2015, thus including several discontinuities in solar activity. Our main challenge now is to provide a 3D map
(geographic/geomagnetic coordinates plus time) of the auroral activity in the
past, when auroral observations constitute the only information available about
heliospheric activity. So far as we know, it is the first time that this task has
been attempted, because previous work has mainly been based on the number
of auroras and/or on limited regions of the Northern Hemisphere. Our final
challenge will be to investigate the main characteristics of the last Gleissberg
cycles of auroral activity, including the Maunder Minimum. In short, we are
interested in the space climate during the last 415 years.
2. The auroral catalogue: general characteristics
For the present work, we selected the geographical coordinates of every site
at which an aurora had been visible. This allowed geographic coordinates to be
ascribed to each observation. If necessary, a selection was made from the existing
sample to give the broadest coverage in both longitude and latitude. When more
Vázquez et al.
data were available for an auroral event, all of them were included, combining the
different sources, except that very close sites were only represented by one record.
Indeed, in general, we tried to exclude from our catalogue any multiplicity due
to sites that are near together, say, differing by less than one degree in position.
Figure 1 shows the histogram of the number of observations per auroral event.
Broadly speaking, the more powerful the event, the more observing sites there
were per day.
0.5
Relative Frequency
0.4
0.3
0.2
0.1
0.0
0
2
4
Number of Sites per Day
6
8
Figure 1. Histogram of the number of available observations per auroral event. Those events
with more than seven observations are included together under the number 7. Blue: Europe
and North Africa. Red: North America.
The number of nights in the period studied (1600 – 2015) was approximately
125 000 (400 years)1 . Therefore we have a coverage of approximately 35% of the
available nights. The available data for the Northern Hemisphere were divided
into three continental domains corresponding to Europe (and North Africa),
North America, and Asia. Table 1 lists the numbers of observations and auroral
events for each of these continental domains.
The first sources of data for the earliest centuries of our sample were the catalogue of Fritz (1873) and the archives of S. Silverman2 . Fritz’s North American
data are mainly based on the earlier catalogues of Lovering (1866) and Loomis
1 We
have excluded those summer days in high latitudes, where the aurora borealis cannot be
seen.
2 These
include: (i) the Catalog of Ancient Auroral Observations, 666 BCE to 1951; (ii) the
Auroral Notations from the Canadian Monthly Weather Review; (iii) the New England Auroral
Aurora Borealis
Table 1. Total number of auroral events and observations in the
three domains of our sample.
ZONE
EUROPE
NORTH AMERICA
ASIA
Auroral events
Number of observations
39 612
32 600
1 195
80 132
79 752
2 321
(1860, 1861). They are complemented for the later phase of the 19th century
with data from Greeley (1881).
For Europe, the Fritz data were complemented with additional values for high
latitudes from Rubenson (1882) and Tromholt3 (1898). Particularly relevant are
the Greenland observations contained in the Fritz catalogue and the Silverman
archives (see Stauning, 2011). For the rare low latitude observations, we also
included data for the Iberian Peninsula4 and the Canary Islands (Vázquez and
Vaquero, 2010).
Some of the early Arctic expeditions in Canada and Alaska did not keep an
appropriate record of the aurorae boreales that were observed5 . On the contrary,
only a few cases of low-latitude events have escaped detection, and events of that
type have often been described in historical reports and/or scientific papers.
The data sample is clearly inhomogeneous in both space and time. This reflects not only meteorological variations but also the difficulties of access to some
regions with the consequent low population density. This is especially notable
for Asia, where large areas are practically unpopulated. For North America,
there are many temporal gaps up to 1746, and, after that, no data are available
for the years 1754, 1755, 1756, 1766, 1799, 1810, or 1812. There is a remarkable contribution for the entire period studied from numerous forts (more than
60) located along the borders of the expanding settlement of the western and
northern territories. Therefore, we assume that an aggregated data set, as is the
present case, would give the same result as an integrated data set (see Silverman,
1985). Indeed, this is an approach that we have to take in order to handle the
extended period of time we are trying to cover.
For the 20th and 21st centuries, we have included many other sources (see
Tables 2 and 3). A non-negligible part of our data comes from popular media of
different types, such as newspapers and, in the last decades, internet resources.
Observations (1720 – 1998); and (iv) the Daily Auroral Reports Southeastern Canada and
Northeastern US (1848 – 1853).
3 For
a biography of S. Tromholt see Moss and Stauning (2012).
4 These
include published data from Vaquero, Gallego, and Garcı́a (2003), Vaquero and Trigo
(2005), Aragonès Valls and Orgaz Gargallo (2010), and Vaquero et al. (2010).
5 ”This
phenomenon having been described by many authors, some of whom have exhausted
the powers of language in the elegance of their representations, renders it unnecessary for me to
attempt any general description of this interesting spectacle.” W. Scoresby (1820) The Arctic
Regions, Vol. I p.416. See also C.I. Jackson (2013) The Voyage of David Craigie to Davis Strait
and Baffin Bay (1818), The Journal of the Hakluyt Society.
Vázquez et al.
Table 2. Catalogues used for the auroras observed in Europe. BAA stands for
British Astronomical Association, and WDCA for World Data Center for Aurora,
Japan. The Observatories Year Books, containing auroral observations, were published by the Meteorological Office. The archives of S. Silverman are available at
http://spdf.sci.gsfc.nasa.gov/pub/data/aaa historical aurora/
Reference
Start-End Observations
Fritz (1873)
Link (1964)
Angot (1897)
BAA
WDCA, Japan
Space Weather
1600–1874
1600–1700
CONTINENTAL
REGIONAL
Sweden
Norway
Finland (all-sky)
Finland
Denmark
Netherlands
Hungary
Croatia
Iberia
Germany
United Kingdom
LOCAL
Berlin
Sunderland, UK
Stroud, UK
Canary Islands
1970–2008
1957–1974
2000–
Rubenson (1882)
Tromholt (1898)
Nevanlinna and Pulkkinen (2001)
Finnish Aurora Observers
Lassen and Laursen (1968)
Visser (1942)
Réthly and Berkes (1963)
Lisac and Marki (1998)
Aragonès Valls and Orgaz Gargallo (2010)
Schröder (1966)
Polarlicht Archive
Obs. Year Book
1716–1877
1973–1997
2000–
1960–1966
1732–1940
1523–1960
1737–1991
1700–
1882–1956
1938–
1923–1964
Kassner (1941)
N/A (1902)
Harrison (2005)
Vázquez and Vaquero (2010)
1707–1770
1860–1900
1771–1805
1770–2003
For publications with an especial emphasis on low-latitude aurora observations,
see Gartlein and Moore (1951), Tinsley et al. (1986), Vallance Jones (1992), and
Shiokawa, Ogawa and Kamide (2005).
Figure 2 shows the locations of auroral observations, on a Mercator projection, of the Northern Hemisphere. The map clearly mimics the distribution
of the human population in the Northern Hemisphere6 . Tables 4 and 5 list the
regions where most auroral events were reported for Europe and North America,
respectively. The number of sites is clearly low for Eastern Europe, as it also was
for Asia.
For the Asian data we used data from the sources listed in Table 6. We shall
discuss these events in detail later in the paper.
6 See
one of the pictures of Earth at Night.
Aurora Borealis
Table 3. Catalogues used for the auroras observed in North America. BAA stands for British
Astronomical Association and WDCA for World Data Center for Aurora, Japan.
Reference
Fritz (1873)
Greeley (1881)
Silverman
BAA
WDCA
Different Reports
Space Weather
1600–1874
1873–1879
1970–2008
1957–
1600–2015
2000–
Broughton (2002)
Mende et al. (2008)
Vestine (1944)
1769–1821
1997–2015
1932–1933
Lueders (1984)
Bond et al. (1889)
Barnard (1902)
Barnard (1909)
Stetson and Brooks (1942)
Silverman and Blanchard (1983)
Milton (1969)
Milton (1962)
1859–1884
1840–1888
1897–1902
1902–1909
1885–1940
1883–1931
1953–1961
CONTINENTAL
REGIONAL
Canada
THEMIS/GAIA Keograms
Polar Years
LOCAL
Washburn Observatory
Harvard Observatory
Yerkes Observatory
Blue Hill
Jericho, Vermont
Edmonton
Table 4. Regions and countries where auroras were most frequently
observed in Europe. Balkans includes the following present countries:
Slovenia, Croatia, Bosnia-Herzegovina, Serbia, and Montenegro. Central Europe: Austria, Czech Republic, Slovakia, and Hungary. Black
Sea: Bulgaria, Romania, and Turkey. Finally, Macaronesia includes the
archipelagos of the Azores, Madeira, and the Canary Islands.
Greenland
Fennoscandia
Iceland
Germany
BeNeLux
Central Europe
Poland
Arctic Islands
Iberian Peninsula
Baltic States
Balkans
Macaronesia
Malta
9589
9079
4787
2643
1710
655
523
342
155
54
52
14
3
Scotland and North Sea Islands
Southern Scandinavia
England and Wales
European Russia
France
Ireland
Italy
Switzerland
West Atlantic (ships)
Greece
Black Sea
North Africa
9047
8487
2956
1825
1244
516
481
215
134
49
26
13
Vázquez et al.
Table 5. States (US), provinces and territories (Canada) in which
auroras were most frequently observed in North America. New
England includes Massachusetts, Maine, New Hampshire, Vermont,
Connecticut, and Rhode Island.
New England
Quebec and Eastern Canada
Manitoba
Alberta
New York
Saskatchewan
Northwest Territories
Nunavut
Michigan
Ohio
Virginia
Wyoming
Illinois
Indiana
Colorado
California
North Carolina
Texas
Kentucky
South Carolina
New Mexico
Arizona
Eastern Atlantic
Florida
Mexico
6818
4896
4191
3926
2575
2343
2155
1220
1043
898
727
544
516
449
278
194
109
94
57
50
39
37
32
32
16
Ontario
North Dakota
Alaska
Montana
Wisconsin
Minnesota
British Columbia
South Dakota
Iowa
Pennsylvania
Washington State
Nebraska
Missouri
Idaho
Kansas
Oregon
Nevada
Tennessee
Arkansas
Utah
Alabama
Oklahoma
Western Pacific
Caribbean Sea
Hawaii
5882
4900
4106
3043
2437
2196
1474
1134
951
763
552
526
523
309
266
104
95
91
53
41
36
33
10
24
2
Table 6. Catalogues used for the auroras observed in Asia. WDCA stands for World Data
Center for Aurora, Japan.
Reference
Fritz (1873)
Silverman
Different Reports
1600–1874
CONTINENTAL
REGIONAL
Korea
Korea
Arab Countries
China, Korea, and Japan
China and Japan
Siberia
Xu, Pankenier and Jiang (2000)
Lee et al. (2004)
Basurah (2004)
Yau, Stephenson and Willis (1995)
Willis, Stephenson and Fang (2007)
Willis, Henwood, Stephenson (2009)
Willis et al. (2005)
WDCA
1600–2015
1600–1662
1105–1779
–1770
1840–1911
1957–2004
–1910
1957–1962
Aurora Borealis
Figure 2. Sites, indicated by black bullets, where auroras were visible at least once in
the Northern Hemisphere during the period studied: 1600 – 2015. The Mercator projection
exaggerates the areas close to the geographic pole.
The histograms of the latitude distributions for Europe and North America
(Figure 3) both suggest a bimodal distribution, with the maxima at middle or at
high latitudes for North America and Europe, respectively. The expected trend
would be more auroral events observed at high latitudes, but in the case of
North America the histograms clearly reflect the slowly progressing settlement
of the northern areas. Examples are the northern US states of Oregon and Idaho
which present relatively few reports due to this population effect. Also, access to
southern data was delayed until these regions (Louisiana, Florida, Texas, New
Mexico) were annexed by the USA. A search of 18th century sources in Spanish
documents would therefore be interesting for this region.
The latitude distribution of the European records shows more discontinuities,
reflecting the existence of interior seas (North, Baltic, Mediterranean, etc.).
We checked the relationship between the auroral observations in these catalogues and moonlight, since an aurora should be easier to observe when there is
little moonlight during the night. In particular, the light of the full Moon would
impede the observation of weak auroras. Therefore, we expected relatively more
(fewer) reported auroras when there was a new (full) Moon. Indeed, we found
that there was a clear decline in observed events with increasing brightness of
the Moon.
3. Latitudinal Variation: Solar Source of the Auroras
As stated in the introduction, the IMF (also called Heliospheric Magnetic Field,
HMF) forms a link between the magnetic flux at the top of the solar atmosphere
(open magnetic flux, OMF) and the Earth’s environment (Owens and Forsyth,
2013; Lockwood, 2013). This connection can be distorted temporally mainly by
two agents, giving rise to auroras, among other effects.
i) Coronal mass ejections, CME: They are transient phenomena linked to
large-scale reorganizations, reconnection, of the magnetic field in closed configurations (active regions). They consist of a massive burst of solar ionized particles
Vázquez et al.
Figure 3. Histograms (independently normalized) of geographic latitudes for Europe, North
America, and Asia using the different catalogues.
threaded with magnetic field lines, ejected from the Sun over the course of a few
hours. The CME rate closely follows the solar cycle, expressed by the sunspot
number (Webb and Howard, 1994; Robbrecht, Berghmans and Van der Linden,
2009) and the Gnevyshev double peak (Gnevyshev, 1967; Feminella and Storini,
1997), but the main physical parameters of CMEs lag the sunspot number by
1–2 years (Gonzalez et al., 1990; Du, 2012).
ii) High-speed streams: Large-scale magnetic regions in the solar atmosphere
have field lines open outwards to the interplanetary medium, the so-called coronal holes (CH). Long-lived coronal holes are sources of high-speed streans in the
solar wind, and are related to recurrent geomagnetic activity (Krieger, Timothy
and Roelof, 1973). Low-latitude CHs occur more frequently in the declining
phase of the sunspot cycle (Verbanac et al., 2011).
Figure 4 shows the temporal variation of estimates of the sunspot number
(Clette et al., 2014) and open magnetic field (Solanki, Schüssler and Fligge,
2000). Usoskin et al. (2002) carried out simulations of the variations of the OMF
with a model based on the emergence and decay rates of active regions (Solanki,
Schüssler, and Fligge, 2002). That model fits other proxies of solar activity, such
as the 10 Be records in ice cores, reasonably well. There is a clear maximum at
Aurora Borealis
the beginning of 17th century, followed by the Maunder Minimum (no yearly
data are available; see however Owens, Usoskin and Lockwood, 2012), and the
rapid increase in the 18th century (Alanko-Huotari et al., 2007). This behaviour
will be studied in the next section in detail with our auroral observations.
Figure 4. Temporal variation of the open magnetic field (solid lines) and the Sunspot Number
(courtesy: M. Schüssler). The Sunspot Number values before the Maunder Minimum are from
Usoskin, Mursula and Kovaltsov (2003) and Vaquero et al. (2011).
Siscoe (1980) discriminated between auroras that are visible north and south
of 54 degrees using Scandinavian records, noting that the southern data tracked
the 11-year solar cycle more clearly. The Greenland observations confirmed that,
at high latitudes, the aurora maximum coincides with the sunspot cycle minimum7 , and confirmed in many later publications. Bravo and Otaola (1990)
studied the location of solar coronal holes and their influence on the auroral
records. They found that the number of auroras is positively correlated with
polar coronal holes that reach solar latitudes below 60 degrees. Verbanac et al.
(2011) found that high-speed streams originating in equatorial coronal holes are
the main driver of geomagnetic activity in the declining phase of the solar cycle.
In order to differentiate between the distinct solar sources, we plotted the
cumulative values, NLat,j , of the number of auroras visible for each 1.5 degree
wide latitude band. These values were computed using the formula
NLat,i =
X
nLat,j .
(1)
The increase found is almost exponential. We took the resulting curve to
consist of three segments, to each of which we made straight-line fits. The intersection of the three segments could represent the boundaries between different
solar sources of the auroral event. The three pairs of plots of Figure 5 show the
results for Europe, North America, and Asia, respectively.
7 This
is based on calculations made by S. Tromholt analysing the observations made in
Greenland by M. Kleinsmidt at Godthaab (cited in Lemström, 1886, pp. 40-41).
Vázquez et al.
The low-latitude segment would represent the auroras produced by strong
solar storms, with the northern limit at 49 degrees in Europe and 39 degrees
in North America. This would define the so-called low-latitude auroras. The
middle segment corresponds to auroral events produced by CMEs of medium
strength. In the upper latitude segment, the predominant role is played by the
fast streams from coronal holes. In this case, the variation of the geographic
latitude plays only a minor role. The limits are approximately 66 degrees for
Europe and 44 degrees for North America. One must take into account that
high-latitude auroras also occur when CMEs hit the Earth during an episode of
northward polarity of the IMF (Cumnock, 2005; Cumnock et al., 2009).
Figure 5. Cumulative values of the number of auroras visible per 1.5 degrees latitude bin (see
the text for explanation). Top panel: Europe and North Africa. Middle panel: North America.
Bottom panel: Asia. The panels on the right are plots on a logarithmic scale.
The latitude distribution is flat-topped at high latitudes (low activity) and
with a linear decrease towards low-latitude auroras (high activity). Hapgood
(2011) reported a similar behaviour for the occurrence frequency of the geomagnetic index aa, typical of a power-law distribution. A parabolic shape
Aurora Borealis
gives a suitable fit to the data, with most of the shoulder being avoided in
the calculation:
log N = (−6.0 ± 0.3) + (0.29 ± 0.01)φ − (0.0019 ± 0.0001)φ2 EU ROP E
(2)
log N = (−8.6 ± 1.1) + (0.48 ± 0.05)φ − (0.004 ± 0.0006)φ2 N ORT HAM ERICA
(3)
log N = (−0.9 ± 0.5) + (0.10 ± 0.02)φ − (0.0007 ± 0.0002)φ2 ASIA
(4)
where φ is the geographic latitude in degrees.
4. Temporal Variation
The 11-yr cycle was the first hint of solar variability of magnetic origin (Schwabe,
1844). There followed the suggestion that longer cycles might exist (Gleissberg,
1939, 1944, 1967) with quasi-periodicities in the range 80–120 years.
In the present study, we are mainly interested in time scales longer than the
11-yr solar cycle. The existence of variability of the solar activity at these scales
(100–1000 yr) has been interpreted in terms of chaotic fluctuations of the solar
dynamo, and is identified as a phase catastrophe of the 11-yr cycle in the records
(Kremliovsky, 1994; Choudhuri and Karak, 2012; Pipin, 2014).
Different proxies have been used to study the past solar activity. The Sunspot
Number has clearly been the most often used. Another is based on the anticorrelation of solar activity with the galactic cosmic ray flux, and thus with the
abundance of cosmogenic isotopes stored in different terrestrial reservoirs. For
reviews concerning the long-term variation of solar activity, see Usoskin (2013).
Using different proxies, Peristykh and Damon (2003) and Ma (2009) have
found a persistence of the Gleissberg cycle over 7000 and 12 000 years, respectively. Usoskin et al. (2004) have reconstructed the Sunspot Number from
10
Be records, finding a 600 yr periodicity together with the Gleissberg cycle.
Hanslmeier et al. (2013) found that various solar proxies are affected by different
non-solar factors, and reflect only the solar activity at long-term scales (> 80
yr). Following estimations of cosmic ray intensities based on 10 Be measurements,
McCracken et al. (2013a) suggested the existence of great stability in the Gleissberg cycles (87 yr and multiples). In a later paper (McCracken et al., 2013b),
they determined the timing of 26 Grand Minima with an average duration of
50-100 years (see also Usoskin, Solanki and Kovaltsov, 2007).
The following are some of the recent findings that particularly stand out.
McCracken (2007) shows that the level of the HMF has increased from 1500 to
the onset of the present century, with maxima occurring in 1735, 1780, 1850,
and 1950. Based on nitrate concentrations measured in ice cores, McCracken et
al. (2001) indicate the existence of well-defined maxima of solar proton events
Vázquez et al.
reaching the Earth for the years 1610, 1710, 1790, 1870, and 1950. And Traversi
et al. (2012) detected Gleissberg cycles in their measurements of nitrate contents
in an Antarctic ice core to study the solar variability during the Holocene, thus
providing an independent test of their long-term existence. However, this result
has been disputed by several authors (Wolff et al., 2012; Duderstadt et al.,
2014), who showed that nitrate cannot be a reliable tracer of solar energetic
particle (SEP) events. On the other hand, Traversi et al. (2012) have indicated
that the use of nitrate is useful to trace the variability of Galactic Cosmic Rays
(GCR), detecting Gleissberg cycles in their measurements of nitrate contents
in an Antarctic ice core and studying the solar variability during the Holocene.
Therefore, they provide an independent test of their long-term existence.
The solar equatorial rotation rate and its latitude variation are related to the
level of magnetic activity (Balthasar, Vázquez, Wöhl, 1986; Casas, Vaquero and
Vázquez, 2006). For past times, it has been determined from sunspot drawings
made in different epochs. Javaraiah, Bertello and Ulrich (2005) have detected
changes in the latitudinal rotation gradient with a periodicity close to 80 years,
similar to the length of a Gleissberg cycle. Mouradian (2013) has suggested
that the sunspot rotation rates show a 54.7 yr periodicity, putting forward the
view that this should be the parameter that defines a long-term cycle, with the
Gleissberg cycle being just a harmonic (109.4 years).
The analysis of different auroral catalogues shows a quasi-80-year periodicity
– the Gleissberg cycle (Hansteen, 1831; Siscoe, 1980; Feynman and Fougere,
1984). Feynman and Ruzmaikin (2014) confirm that the extremes of the auroral distribution are consistent with a Gleissberg cycle, also reflected in the
Sunspot Number but differing in phase. Riley (2012) has studied the problem
from another perspective, estimating that a Carrington-like event has a 10 percent chance to occur in a decade, and implying a 100-yr periodicity in the low
latitude records. Yermolaev et al. (2013) suggests that a Carrington-1859 storm
is observed only once every ∼ 500 years.
Figure 6 gives an overview of the temporal and latitudinal variation of the
auroral observations recorded in our sample. Additional information is provided
by Figure 7 with plots of the yearly number of auroras in our catalogue. Both
figures reflect the population effects commented on in previous sections. However,
our main interest lies in the long-term variation of solar activity, and for this
purpose we divide our sample into the seven subperiods discussed in the following
subsections.
4.1. The Maunder Minimum (1645-1715)
Some decades after the discovery of the 11-yr cycle in sunspot records (Schwabe,
1844), Spörer (1889) and Maunder (1894) reported the existence of a period in
the second half of the 17th century when sunspot activity was markedly reduced
– the Maunder Minimum (hereafter, MM). Eighty years later, in a seminal paper,
Eddy (1976) revived the topic, bringing new proofs and associating the episode
with the Little Ice Age.
Gleissberg, Dambolt and Schove (1979), Schröder (1988), and Schlamminger
(1990) reported auroral observations which confirmed that the heliosphere during
Aurora Borealis
Figure 6. Temporal and latitudinal variation of aurora borealis events visible during the last
four centuries as reported in different archives (see Table 2) in (top) Europe and North Africa,
(middle) North America, and (bottom) Asia.
this period presented the 11-yr periodicity. The same behaviour was found by
Nesme-Ribes and Ribes (1993) based on sunspot observations for 1660-1719,
although they detected a strong north-south asymmetry in the sunspot locations (see also Vaquero, Nogales and Sánchez-Bajo, 2015). Other studies have
discussed the 11-yr period during the MM (Beer, Tobias and Weis, 1998; Usoskin,
Mursula and Kovaltsov, 2001). Recently, Vaquero et al. (2015) have proposed
that the solar cycle was shorter during the MM (approximately 9 years).
Vázquez et al.
Figure 7. Annual aurora borealis number.
Auroral events occurred during this period when no sunspots were present
on the solar disk (Leftus, 2000). Owens and Lockwood (2012) calculated that
the CME rate during this episode was similar to that of the two recent solar
minima. More recently, Zolotova and Ponyavin (2015) proposed on the basis of
sunspot data that the MM seems to be an ordinary Gleissberg Minimum with a
depressed 11-yr periodicity. This was contested however by Usoskin et al. (2015)
arguing that solar activity during the MM was very low, although the exact level
is still unclear.
The presence of a strong red flash during two eclipses in 1706 and 1715 that
occurred in the MM would require a substantially high solar magnetic field
strength (Foukal and Eddy, 2007). Riley et al. (2015) used a magnetohydrodynamics model with the pertinent observational constraints, finding that the
configuration of the corona at the recovery after the deep Maunder minimum
was not typical of Schwabe or Gleissberg Minima. In an analysis of sunspot
drawings, Casas, Vaquero and Vázquez (2006) found an anomaly in the solar
rotation during the deep MM compared to determinations made before and
after this episode.
According to Sokoloff (2004), the transition to the deep minimum was abrupt,
while the end was fairly gradual. However, Vaquero et al. (2011) revised the
sunspot numbers around 1640 and found that the transition to the deep minimum was also gradual. For the period before the MM, Leftus (2000) found that
there were peaks in the sunspot number in 1614, 1624, and 1639 (see Figure 4).
A recent analysis of historical sunspot data by Vaquero et al. (2015) indicates
Aurora Borealis
the existence of sunspot number peaks also in the deep minimum, namely in
1655–1657, possibly 1666, 1675, 1684, and 1705. In the auroral records of the
present study (Figure 8), one can see relatively strong activity in the first decades
of the 17th century, followed by the Maunder episode which presents a 20-year
quasi-periodicity until its end, similar to the dominant cycle that Usoskin et al.
(2001) found with clusters of sunspot occurrences.
Figure 8. Annual aurora borealis numbers during the 17th century in our records. Europe
and North America (dashed line) and the total of Europe, North America, and Asia (solid
line).
The lack of auroras visible at high and low latitudes in our data, does not
allow any clear statement to be made about the consideration of the MM as a
Grand Minimum or just a Gleissberg Minimum. In this context, the Asian data
are essential, but, as will be seen below, they are still highly controversial with
regard to their reliability.
4.2. The 18th century rise in solar activity (1715-1800)
4.2.1. The rise in solar activity
After the MM, with the clear rise in solar activity, the works of Halley (1716)
and Mairan (1733) marked the beginning of modern studies of auroras, in which
there was a dramatic increase in the number of aurora reports.
The middle panel of Figure 6 reflects the paucity of North American data
during the 18th century, especially at high latitudes. As the settlement of the
western regions progressed, there was a concomitant increase in the number of
reports. The New England records are, however, relatively frequent over the
Vázquez et al.
whole period. The bottom panel of that figure reflects how few data we were
able to find for auroral observations in Asia.
The strongest auroral event during this interval occurred on 18 January 1770
(Vázquez, Vaquero and Curto, 2006; Schröder, 2010). It was visible in North
Africa. Also remarkable in the same year were the events of 16-18 September
(Willis and Stephenson, 1996), observed in China and Japan and also visible at
low latitudes in Europe (Vázquez and Vaquero, 2010).
4.2.2. The lost cycle
A 15-yr cycle (Schwabe Cycle Number 4) took place at the end of this period
of rise in solar activity (1790 approximately). Usoskin, Mursula and Kovaltsov
(2001) proposed that in fact there existed two cycles in this period. Later,
Usoskin et al. (2009) constructed butterfly diagrams for the period, finding that
high-latitude sunspots were present in 1793, an indicator of the start of a new
cycle. A recent Bayesian analysis of 10 Be records (Karoff et al., 2015) seems to
support this hypothesis. Our records (Figure 9) show first the standard Cycle
4 and then an extended decay tail with a hint of a secondary maximum (see
also the records of Krivský and Pejml, 1988, and Legrand and Simon, 1987).
However, it is still unclear whether it was a new cycle or just a burst of activity
(Zolotova and Ponyavin, 2011).
Other factors could also have played a role in the decrease of observations.
For example, the eruption of the Laki volcano in Iceland (1783–1784) emitted
much dust into the European (Thordarson and Self, 2003) and South American
(Trigo, Vaquero and Stothers, 2010) skies.
4.3. The Dalton Minimum (1790–1830)
Named after John Dalton (1766–1844) who kept a meteorological journal for 57
years, including aurora borealis observations (Dalton, 1873), the Dalton Minimum in sunspot numbers also corresponded to a reduction in the number
of auroras observed (Silverman, 1992; Broughton, 2002; Vaquero, Gallego and
Garcia, 2003), as is clearly confirmed in our European data. (We remedied the
lack of high-latitude records in the Fritz catalogue by including the Scandinavian
observations of Tromholt and Rubenson.) The auroras observed in Barcelona in
1811 and 1812 are remarkable, and call for detailed confirmation.
4.4. The new 19th century rise in solar activity
The 19th century period of a rise in solar activity is full of strong auroral
events, including the famous Carrington aurora (1859, 28 August and 2 September), a paradigm of solar-terrestrial relationships (Kimpball, 1960; Cliver and
Svalgaard, 2004; Silverman, 2006; Cliver and Dietrich, 2013). Some years later,
there occurred the events of 24 January 1870 and 4 February 1872 (Silverman,
2008). Taken together, these represent the highest peak of auroral activity in
our sample.
Observations of high-latitude auroras were favoured by the organization of
the first International Polar Year campaign (from 1881 to 1884), producing
Aurora Borealis
Figure 9. Annual aurora borealis number at the end of the 18th century in Europe and North
Africa.
an accumulation of recorded high-latitude events that is visible in our plots.
See Raspopov, Kuz’min, and Kharin (2007) and Barr and Lüdecke (2010) for
descriptions of the various International Years that are related in some way with
auroral observations.
Uberoi (2011) reports an auroral observation of the 1872 event in Aden, at
12 degrees north geographic latitude8 . That this would imply a geomagnetic
latitude of only 2 degrees raises severe doubts about the observation’s reliability.
We have therefore excluded it from our records9.
4.5. The Gleissberg Minimum of solar activity (1880–1910)
At around the turn of the 19th to the 20th century, the level of auroral activity
again decreased, a fact that has already been remarked on in previous studies.
The records of the geomagnetic index aa show a clear minimum at around 1901.
Brown (1976) detected a minimum of the Gleissberg cycle at the end of Cycle
13, around 1902.
Since Solar Cycle 14 (1902 – 1913), the geomagnetic activity has lagged behind
the sunspot number, but before that date the lag seems to have been less notable
(Love, 2011). Lockwood and Owens (2014) found that, during the minima of
8 Published
in the Times of India with the remark ”The aurora was brilliant in the extreme”.
9 The
same attitude was taken to an observation of the 1859 event at St George of Mina (now
in Ghana) at 5 degrees north geographic latitude, contained in the Fritz catalogue.
Vázquez et al.
11-year Schwabe cycles at around 1879 and 1901, the average solar wind was
exceptionally low, implying that the Earth remained within the streamer belt of
slow solar wind flow for extended periods.
Balthasar, Vázquez and Wöhl (1986) in analysing sunspot records detected a
decline in the solar rotation in around 1902 between Schwabe Cycles 13 and 14,
bringing to mind the recent proposal by Mouradian (2013) of the importance of
this parameter for the long-term behaviour of the solar dynamo.
4.6. The 20th century
Particularly remarkable is the marked drop in the quantity of data for the period
1960-1980 in all three samples. An explanation could be the changing way that
theories about auroras were developed. For many centuries, auroras were mainly
regarded as an atmospheric phenomenon, with reports by laymen being later
incorporated into the meteorological record. There was a gradual growth of
awareness of their connection with solar activity and geomagnetic perturbations
(Maunder, 1905). Routine observations were abandoned, and interest in them
shifted to geophysicists studying the physics of isolated events (Legrand and
Simon, 1987). Odenwald (2007) studied the yearly number of aurora reports
appearing in newspapers. He found a sharp reduction after 1960, probably a
result of the coming of the “space age” and the popularization of television.
Nonetheless, this effect was partially compensated by the various auroral observation campaigns organized in the framework of the International Geophysical
Year (IGY). These campaigns mostly affected the period 1957–1960, and they
had a certain clear bias towards high-latitude sites10 .
In the 1990s the diffusion of digital images over the Internet led to a new
increase in observations. Moreover, all-sky imaging programs were started, such
as those corresponding the GAIA and THEMIS consortia (Mende et al., 2008).
In order to allow a certain normalization with older data, we have taken especial
care to select only strong events so as to make the digital images comparable
with the photographic and visual observations of the past.
The start of this period is marked by the strong auroral events of 25 September
1909 (Silverman, 1995) and 14-15 May 1921 (Silverman and Cliver, 2001). A
later outstanding event is that of 25 January 1938 which was widely reported
in the press (Barlow, 1938). Also remarkable is the strong activity of Cycle 19,
peaking as the maximum of a long-term cycle in 1957, just at the start of the
aforementioned IGY campaigns,
The CME of 4 August 1972 also merits particular comment because it had
the appropriate parameters for it to become a superstorm similar to that of the
Carrington 1859 event (see Gonzalez et al., 2011, for references), but in auroral
records of our catalogue it was only visible as a moderate event. The polarity
of the IMF was directed northwards, thus avoiding a massive input of particles
towards low-latitude sites. This is a good illustration of why many parameters
must combine to produce a super-event.
10 These
data are stored at the World Scientific Center for Aurora, Japan.
Aurora Borealis
The aurora of 13 March 1989 (Shirochkov et al., 2015) marked an inflection
point in public interest in space weather studies and their technological influences. The well-known blackout of Quebec and nearby areas has been studied in
detail (Boteler, 2001; Hapgood, 2011) and popularised in the press.
More recently, in Schwabe Cycle 23, there occurred the so-called “Halloween”
period of strong solar activity, with two phases of activity in October and November of 2003 (Kane, 2005). The first phase was concentrated in the days between
19 October and 12 November. Spacecraft as distant as Ulysses, Cassini and
Voyager 2, were able to detect the enhancements of solar particles, corresponding
to distinct CMEs, at different heliocentric distances (Burlaga et al., 2005; Lario
et al., 2005). In the second phase, an event on 20 November was associated with a
large geomagnetic storm (Karavaev et al., 2009) produced by a halo CME. What
made this event special, however, was the high IMF and its strong southward
component (Gopalswamy et al., 2005; Srivastava et al., 2009). The duration of
the solar wind–magnetosphere interaction was very long – 13 hours (Srivastava,
2005). The corresponding aurora was observed at very low latitudes (Vázquez
and Vaquero, 2010). For mid-latitude observations in Asia see Mikhalev et al.
(2004).
4.7. The recent minimum (2006–2009)
The last minimum of solar activity, between Cycles 23 and 24, has attracted the
attention of solar astronomers due to its extended duration and the low values
of solar irradiance measured during this interval (Fröhlich, 2013) .
According to McCracken and Beer (2014), the measured levels of cosmic rays
are incompatible with the existence of a Grand Minimum in the present times.
Rather, they reflect a minimum of the Gleissberg cycle. Echer, Tsurutani and
Gonzalez (2011) showed that the low levels of solar and geomagnetic activity
are similar to the previous Gleissberg minimum at the beginning of the 20th
century.
The present Cycle 24 is characterized by a small amplitude, typical of the
extended phase of a Gleissberg Minimum. However, strong auroral events could
yet occur in this cycle. Indeed, the weak sunspot activity for Cycle 24 is not seen
in the CME occurrence of the same period (Jian, Russell and Luhmann, 2011).
Gibson et al. (2011) remark that during this episode the Earth was periodically
impacted by high-speed streams originating from long-lived coronal holes, which
suggests an unusual configuration of the large-scale solar magnetic field, at least
compared with the previous cycle. Based on an analysis of nitrate records in ice
cores, Barnard et al. (2012) suggest that a return to low levels of solar activity
will indeed lead to a decrease in the auroral frequency, but also to an increase in
the average fluence per auroral event. This calls to mind the sporadic low-latitude
auroras occurring in relatively quiet periods.
Helioseismic measurements with different ground- and space-based instruments (Broomhall et al., 2009; Salabert et al., 2011; Jain, Tripathy and Hill,
2011) indicate changes in the frequencies of acoustic p-modes during the extended minimum, interpreted as changes in the magnetic field deep in the convection zone, including a possible role for a deep-seated relic magnetic field in
the solar interior.
Vázquez et al.
Auroral records of our catalogue show some features typical of a Gleissberg
Minimum. However, it would be premature to reach any conclusion in this
respect given the duration of these episodes. One needs to wait and continue
observing, keeping in mind that the geomagnetic effects of solar activity usually
lag the sunspot number.
In summary, our sample can be divided into four long-term Gleissberg cycles.
We cannot conclude whether or not the MM corresponds to one of them due to
the scarcity of low-latitude auroras in the first part of the 17th century. Figure
10 plots the values of the annual minimum latitudes for the auroral events for
Europe and North Africa regions with a better observational coverage.
Figure 10. Annual values of the minimum geographic latitudes of auroral events for Europe
and North Africa (solid lines) and North America (dashed lines).
5. The Geomagnetic Latitude
Since the frequency of auroras is related to distance from the magnetic pole, it
is more appropriate to plot the observations vs. magnetic latitude.
5.1. Model of the geomagnetic field
We computed the temporal evolution of the geomagnetic latitude for every observing location during the entire period of our study. It is common to define
within the main geomagnetic field the geomagnetic latitude φ according to the
Aurora Borealis
expression tan φ = (tan I)/2 (see Buforn, Pro, and Udı́as, 2012). We obtained
the magnetic inclination (I) from the global geomagnetic model gufm1 (Jackson,
Jonkers, and Walker, 2000). This model is based on observational data of the
intensity of the geomagnetic field during the last centuries. The validity of this
model for the last four centuries has been verified by Pavón-Carrasco et al. (2014)
by comparison with archaeomagnetic data.
As an example, Figure 11 represents the pairs of geomagnetic and geographic
latitudes for all the available data. In the plots, we have differentiated the results
calculated with the well-known IGRF (International Geomagnetic Reference
Field) model, valid for the period from 1900 to the present (De Santis, 2007).
Figure 11. Plots of geographic vs. geomagnetic latitudes for all the available data, subdivided
into the three subsamples. Black asterisks: gufm1 model (1600-1989). Red asterisks: the IGRF
model (1989-2015).
Vázquez et al.
5.2. Latitude variation
Figure 12 shows the results of the geomagnetic latitude of auroral occurrence for
Europe, North America, and Asia. One observes the Dalton Minimum between
the two high-activity episodes. However, the low geomagnetic latitudes during
the 18th century are mainly covered by Asian data. Two episodes with highlatitude auroras occur in 1820 and 1840 close to the minimum phase of the
corresponding solar cycles. An unusual aurora was visible close to the geomagnetic North Pole (Fort Conger) on 17 November 1882. These observations were
made by the expedition commanded by A.W. Greeley from July 1882 to August
1883 in the framework of the activities of the First Polar Year (Taylor, 1981).
In this context, Singh et al. (2012) have recently studied the characteristics of
high-latitude storms above the classical auroral oval.
Figure 12. Temporal and geomagnetic latitude distribution of the auroral event observations:
(black diamonds) Europe and North Africa; (red squares) North America; (red triangles) Asia.
Figure 13 shows the histograms of the geomagnetic latitudes for the three
continental areas. There stands out the major contribution of the otherwise
sparse Asian data to the low geomagnetic latitudes. These observations mainly
correspond to a group of exceptionally strong aurora events occurring around
the maximum of one of the strongest cycles of the 19th century, 1872 (see Figure
8).
We repeated the calculation of the cumulative number of auroral events, but
now for the geomagnetic latitudes. The results (Figure 14) show the behaviour to
be similar for the two continents of Europe plus North Africa and North America,
although there are relatively few high geomagnetic latitude observations in the
North American sample (Canada and Alaska). Liritzis and Petropoulos (1987)
Aurora Borealis
Figure 13. Histogram of the geomagnetic latitudes. (Top) Europe and North Africa; (middle)
North America; (bottom) Asia.
already noted that there is a marked change at a geomagnetic latitude of 57 –
58 degrees. Although there are too few Asian data to be significant, they are
included for the sake of comparison, especially in the low-latitude range.
As with the geographic latitudes, we fitted parabolas to the three subsamples.
For Europe, the results were practically identical to those for the geographic
latitudes. They differed slightly for North America. We excluded the Asian data
due to the relatively smaller number of observations.
log N = (−4.6 ± 0.7) + (0.23 ± 0.03)φmag − (0.0013 ± 0.0003)φ2mag Europe (5)
log N = (−3.1 ± 1.1) + (0.16 ± 0.02)φmag − (0.0007 ± 0.0002)φ2mag N orthAmerica
(6)
where φmag is the geomagnetic latitude.
5.3. The Gleissberg cycles
Schove (1955) was probably the first to date the extremes of the last Gleissberg cycles, confirming the existence of a 78-yr periodicity at least since 200
BCE. Feynman and Silverman (1980), using only records from Sweden and New
England, also detected low values of auroral activity during the different Gleissberg Minima. Garcia and Mouradian (1998) calculated the maxima and minima
of Gleissberg cycles after 1750 using sunspot records, and following the same
method as Gleissberg (1960). They were able to study a complete Gleissberg
Vázquez et al.
Figure 14. Cumulative values of the number of auroras below a certain minimum geomagnetic
latitude. (♦) European and N. African sample; (∗) North American sample; (△) Asian data.
Left panel: normal scale. Right panel: logarithmic scale.
cycle (from the Dalton Minimum to the 20th century Minimum), the decay of
the previous cycle, and the peak of the present cycle with the maximum at
around 1957.
Figure 15 shows the annual variation of the minimum latitude reached by
auroral events. The Gleissberg cycle also presents a double peak. The dates of
the secondary maxima have been studied by Hoyt and Schatten (1997). Gonzalez
et al. (2011) suggested that extreme events can be expected to occur at the rate
of about one per century, with a tendency to appear close to the secondary
maximum in the descending phase of the Gleissberg cycle. Table 7 summarizes
the main parameters of these cycles based on our records. We could also have
included a Gleissberg Cycle number 0, elapsing from the Spörer Minimum (year
1570) to the MM, but the auroral data are very limited both spatially and
temporally.
In principle, one might explain the 1848-1872 interval as the maximum of an
approximately 200-year cycle (so-called Suess cycle) of auroral activity (Suess,
1980). Silverman (1995) set a minimum geomagnetic latitude of 15 degrees at
which auroras can be observed. This is surpassed by the observations during this
supermaximum.
Ogurtsov et al. (2002) studied two proxies of solar activity – sunspot number
and cosmogenic isotopes – and found that the Gleissberg cycle has a frequency
band with a double structure consisting of periods of 50–80 yr and 90–140 yr,
whereas the Suess (or de Vries) cycle only presents one period of approximately
210 yr.
Aurora Borealis
Figure 15. Annual variation of the minimum geomagnetic latitude of auroral events. Solid
line, absolute minimum values for North America and Europe plus North Africa. Triangles,
values for Asia.
Table 7. Overall characteristics of the four Gleissberg cycles (GC) in our sample. The dates
are taken from Gonzalez et al (2011). SMAX stands for secondary maximum and GMLmin
for the minimum value of the geomagnetic latitude during the corresponding period. SNMAx
indicates the maximum value of the annual sunspot number, and N is the number of auroras
in the corresponding Gleissberg cycle for Europe and North Africa.
GC
Start
Maximum
I
1700
1770
II
1810
1839
III
1910
IV
2009
SMAX
End
GMLmin (time)
SNMax (time)
N
1809
15
154.4 (1778)
8516
1870
1909
8 (1859)
139.0 (1870)
13 765
1958
1980
2009
18
190.2 (1957)
15 085
–
–
34
..
Figure 16 displays variations of the cumulative numbers of auroras as a function of geographic and geomagnetic latitude of three Gleissberg cycles. Due to
the different amounts of data available in each cycle, we have normalized the
number N of auroras to the maximum value of each cycle.
6. Conclusions
We have presented here the first analysis of a catalogue that aims to summarize
most of the available visual aurora borealis observations from 1600 to the present
day. To this end, latitudes were assigned to more than 160 000 auroral observations. For the analysis, we divided the Northern Hemisphere into three large
Vázquez et al.
Figure 16. Global Variation with the geographic (upper plot) and geomagnetic (bottom
plot) latitudes of the cumulative number of auroras for the Gleissberg Cycles I (solid lines), II
(dashed lines), and III (dashed-dotted lines). Data: Europe and North Africa.
continental areas corresponding to Europe (plus North Africa), North America,
and Asia. The sample had numerous spatial and temporal gaps. This was particularly evident in the North American data due to the progressive European
occupation of large areas beyond the original New England states.
There are some evident gaps in our catalogue. We have commented on them
throughout this communication. The gaps correspond mainly to high and low latitudes in North America for the 17th and 18th centuries, and to many practically
uninhabited places in Asia.
Trying to fill these gaps would therefore be unlikely, apart from finding and
adding some isolated data. In this respect, one can say in synthesis that the
spatial and temporal distribution of auroral observation data is affected at least
as much by the population effect as by the purely geomagnetic effect.
We re-applied a method developed in Vázquez, Vaquero and Gallego (2014)
to separate the contribution of the different solar sources of auroral events. It is
based on the different slopes of the cumulative numbers of auroral events per latitude bin. The low-latitude segment mainly corresponded to strong CMEs taking
place around the solar cycle maxima. The mid-latitude segment corresponded to
standard CMEs, and the high-latitude segment to high-speed streams of solar
wind originating from coronal holes. The limit between these last two sources
lies in a narrow belt between 64 and 67 degrees geomagnetic latitude. One must
bear in mind that the geoeffectiveness of such transitory solar events depends
Aurora Borealis
critically on the level of the IMF and its orientation with respect to the Earth’s
magnetosphere.
The three subsamples of our catalogue presented the same trend in the cumulative number of auroral events vs. geomagnetic latitude. Only a few events
deviated from this behaviour. They corresponded to Gleissberg cycle maxima.
As indicated above, the spatial distribution of the available data is clearly
determined by the populations living at high-latitude sites. These populations
were clearly greater in Europe than in North America. The same may apply to
the low-latitude sites in the two continents. The result may have been to mask
the expected better correlation of the auroral parameters with the geomagnetic
than with the geographic latitude.
Apart from the population effect, the occurrence of specific auroral events of
great strength is driven by chance (see the different cases discussed in Section 4),
but with a notable dependence on the amplitude of the corresponding 11-yr cycle.
However, the long-term behaviour of the auroral activity is clearly driven by a
deterministic process (whether chaotic or not), and particularly by the phase
of the Gleissberg cycle. In other words, there are some short extreme events
inserted into a slowly varying background, and these events are attributable to
high-speed streams from coronal holes. The geomagnetic component due to the
slow solar wind (see Legrand and Simon, 1987, for a classification) is not reflected
in our sample, because any auroras it might produce are very faint.
The observations of low-latitude auroras in Asia are very puzzling. They can
be divided into two groups. First , there are the MM observations at relatively
low geomagnetic latitudes (Willis and Stephenson, 2000). Zhang (1985) noted
that 23 times more auroral observations were reported in Korea during the 15071749 period than in China. The author proposed that they were Stable Auroral
Red Arcs, visible at the edge of the auroral oval, although Kozyra, Nagy and
Slater (1997) argue to the contrary. Nonetheless, by itself, this assumption cannot
explain the southward extension of the Korean observations, especially during
the MM. More recently, Willis and Davis (2015) have presented new evidence for
recurrent auroral activity in 1625 and 1626, a time prior to the MM, evidence
that is fully compatible with other activity indicators (see Figure 4). Whatever
the case, the very low latitude observations in India and Arabia for the 1872
super-event are well documented. A possible factor to consider is the geomagnetic
model we have been using because it is at the edge of its range of reliability for
the 17th century. Even so, any errors that result cannot be so large. Willis and
Stephenson (2000) give a range of geomagnetic latitudes for Asia of 25-38 degrees,
similar to our determinations. In this regard, those same authors (Willis and
Stephenson, 2002) report that the Korean observations during the 17th century
were seen in a southerly direction. Oguti and Egeland (1995) commented that,
given its low geomagnetic latitude, Korea should not have seen auroral activity
in the last 1000 years. Second , there are observations at very low geomagnetic
latitudes during the 19th century super-events, visible as a separate group in
the overall histogram. In this case, however, the observations seem to be very
reliable.
The aim with this first communication using the whole catalogue has been to
present the long-term characteristics of the last Gleissberg cycles – really crucial
Vázquez et al.
to understanding the space climate. It will be followed by others analysing in
detail the spatial and temporal oscillatory patterns, and the potential of such
analyses to contribute to the reconstruction of past heliospheric activity.
Finally, we would like to invite readers to contact the authors in a case
that they have information on auroral observations at sites and/or at times
not included in this paper. The complete catalogue is still in progress and will
be stored in a World Data Center at the end of the project, including also
data of aurora australis. Colleagues interested in this preliminary version of our
catalogue are invited to contact the lead author.
Acknowledgements The authors wish to express their gratitude to Sam Silverman who
undertook the immense task of collecting thousands of auroral reports around the world and
making them available to the scientific community. Some well-known auroral catalogues (Fritz,
Angot) used for this study are from Jack Eddy’s Compilation of Auroral Catalogues and were
obtained from the Research Data Archive (RDA), which is maintained by the Computational
and Information Systems Laboratory (CISL) at the National Center for Atmospheric Research
(NCAR). NCAR is sponsored by the National Science Foundation (NSF). The original data
are available from the RDA (dss.ucar.edu) with dataset number ds836.0. The following persons
provided information and/or data of auroral events: A. Kadokura (WDCA, Japan), M. Connors
(GAIA program, Canada), and K. Erhardi (DMI, Denmark). Support from the Junta de Extremadura (Research Group Grants) and from the Ministerio de Economia y Competitividad of
the Spanish Government (AYA2011-25945 and AYA2014-57556-P) is gratefully acknowledged.
References
Akasofu, S.I.: 2015, History of Geo and Space Sciences 6, 23.
Alanko-Huotari, K., Usoskin, I.G., Mursula, K., Kovaltsov, G.A.: 2007, J. Geophys. Res. 112,
A08101.
Angot, A.: 1897, The Aurora Borealis, D. Appleton & Co., New York (translation of the
original French version published in 1895).
Aragonès Valls, E., Orgaz Gargallo, J.: 2010, Treb. Mus. Geol. Barcelona 17, 45.
Balthasar, H., Vázquez, M., Wöhl, H.: 1986, Astron. Astrophys. 155, 87.
Barlow, E.W.: 1938, Q. J. Royal Meteorol. Soc. 63, 215.
Barnard, E.E.: 1902, Astrophys. J. 16, 135.
Barnard, E.E.: 1909, Astrophys. J. 31, 208.
Barnard, L., Lockwood, M., Owens, M.J., Davis, C.J., Hapgood, M.A., Steinhilber, F.: 2012,
EGU General Assembly, Vienna.
Barr, S., Lüdecke, C. (Eds): 2010, The History of the International Polar Years. Springer.
Basurah, H.M.: 2004, Solar Phys. 225, 209.
Beer, J., Tobias, S., Weiss, N.: 1998, Solar Phys. 181, 237.
Bernard, F.: 1837, Am. J. Sci. Arts 34, 267.
Brekke, P., Broms, F.: 2013, Northern Lights. A Guide, Forlaget Press.
Bond, W.C., Bond, G.P., Winlock, J., Pickering, E.C.: 1889, Annals of Harvard College
Observatory 19, 50.
Boteler, D.H.: 2001, Geophysical Monograph Series 125, pp.347–352, P. Song, H.J. Singer,
G.L. Siscoe (eds), AGU Washington.
Bravo, S., Otaola, J.A.: 1990, Ann. Geophysicae 8, 315.
Broomhall, A.M., Chaplin, W.J., Elsworth, Y., Fletcher, S.T., New, R.: 2009, Astrophys. J.
700, L162.
Broughton, P.: 2002, J. Geophys. Res. 107, 1152.
Brown, G.M.: 1976, Mon. Not. Roy. Astron. Soc. 174, 185.
Buforn, E., Pro, C., Udı́as, A.: 2012, Solved Problems in Geophysics, Cambridge University
Press, Cambridge.
Burlaga, L.F., Ness, N.F., Stone, E.C., Mc Donald, F.B., Richardson, J.B.: 2005, Geophys.
Res. Lett. 32, L03S05.
Casas, R., Vaquero, J.M., Vázquez, M.: 2006, Solar Phys. 234, 379.
Aurora Borealis
Chapman, S.: 1970, Annual Review of Astronomy and Astrophysics 8, 61.
Choudhuri, A.R., Karak, B.: 2012, Phys. Rev. Lett. 109, 965.
Clette, F., Svalgaard, L., Vaquero, J.M., Cliver, E.W.: 2014, Spa. Sci. Rev. 186, 35.
Cliver, E.W., Dietrich, W.F.: 2013, Journal of Space Weather and Space Climate 3, A31.
Cliver, E.W., Svalgaard, L.: 2004, Solar Phys. 224, 407.
Cumnock, J.A.: 2005, J. Geophys. Res. 110, 2304.
Cumnock, J.A., Blomberg, L.G., Kullen, A., Karlsson,T., Sundberg, K.A.T.: 2009, Ann.
Geophysicae 27, 3335.
Dalton, J.: 1873, Meteorological Observations and Essays, London.
De Santis, A.: 2007, Physics of the Earth and Planetary Interiors, 162, 217.
Du, Z.: 2012, Solar Phys. 278, 203.
Duderstadt, K.A., Dibb, J.E., Jackman, C.H., et al.: 2014, J. Geophys. Res. 119, 6938.
Echer, E., Tsuratani, B.T., Gonzalez, W.D.: 2011, Extremely low geomagnetic activity during
the recent deep solar cycle minimum, in IAU Symposium 286, C.H. MAndrini and D.F.
Webb (Eds), pp. 200-210.
Eddy, J.A.: 1976, Science 192, 1189.
Feldstein, Y.I.: 1963, Geomag. Aeronomy 3, 183.
Feldstein, Y.I., Vorobjev, V.G., Zverev, V.L., Förster, M.: 2014, History of Geo and Space
Sciences 5, 81.
Feminella, F., Storini, M.: 1996, Cool Stars, Stellar Systems, and the Sun 109, 127.
Feynman, J., Fougere, P.F.: 1984, J. Geophys. Res. 89, 3023.
Feynman, J., Ruzmaikin, A.: 2014, J. Geophys. Res. 119, A8, 6027.
Feynman, J., Silverman, S.: 1980, J. Geophys. Res. 85, A6, 299.
Foukal, P., Eddy, J.A.: 2007, Solar Phys. 245, 247.
Fritz, H.: 1873, Verzeichniss Beobachteter Polarlichter, C. Gerold’s Sohn, Wien.
Fröhlich, C.: 2013, Spa. Sci. Rev. 176, 237.
Garcia, A., Mouradian, Z.: 1998, Solar Phys. 180, 495.
Gartlein, C.W., Moore, R.K.: 1951, J. Geophys. Res. 56, 85.
Gibson, S.E., De Toma, G., Emery, B., Riley, P., Zhao, L.,Elsworth, Y.,Leamon, R.J.,Lei, J.,
McIntosh, S., Mewalt, R.A., Thompson, B.J., Webb, D.: 2011, Solar Phys. 274, 5.
Gleissberg, W.: 1939, Observatory 62, 158.
Gleissberg, W.: 1944, Terr. Mag. Atmos. Elec. 49, 243.
Gleissberg, W.: 1960, Zeitschrift für Astrophysik 49, 25.
Gleissberg, W.: 1967, Solar Phys. 2, 231.
Gleissberg, W., Dambolt, T., Schove, D.J.: 1979, Journal of the British Astronomical
Association 89, 440.
Gnevyshev, M.N.: 1967, Solar Phys. 1, 107.
Gonzalez, W.D., Echer, E., Clúa de Gonzalez, A.L., Tsuratani, B.T., Lakhina, G.S.: 2011, J.
Atmos. Solar-Terr. Phys. 73, 1447.
Gonzalez, W.D., Gonzalez, A.L.C., Tsurutani, B.T.: 1990, Planetary and Space Science 38,
181.
Gopalswamy, N., Yashiro, S., Michalek, G., Xie, H., Lepping, R.P., Howard, R.A.: 2005,
Geophys. Res. Lett. 32, L12S09.
Greeley: 1881, Chronological List of Auroras observed from 1870 to 1879, Prof. Pap. of the
Signal Service, Government Printing Office, Washington.
Halley, E.: 1716, Phil. Trans. Roy. Soc. London 24, 406.
Hanslmeier, A., Brajsa, R., Calogovic, J., Vrsnak, B.,Ruzdjak, D.,Steinhilber, F., Mac Leod,
C.L., Ivezic, Z.,Skokic, I.: 2013, Astron. Astrophys. 550, 2059.
Hansteen, C.: 1831, Poggendorff ’s Annalen XXII, 536.
Hapgood, M.A.: 2011, Adv. Spa. Res. 47, 2059.
Harrison, G.: 2005, Astronomy and Geophysics 46(4), 31.
Hoyt, D.V., Schatten, K.H.: 1997, The Role of the Sun in Climate Change, Oxford University
Press, Oxford.
Jackson, A., Jonkers, A.R.T., Walker, M.R.: 2000, Phil. Trans. Roy. Soc. London A 358, 957.
Jain, K., Tripathy, S.C.,Hill, F.: 2011, Astrophys. J. 739, 957.
Javaraiah, K., Bertello, L., Ulrich, R.K.: 2005, Solar Phys. 232, 25.
Jian, L.K., Russell, C.T., Luhmann, J.G.: 2011, Solar Phys. 274, 321.
Kamide, Y., Maltsev, Y.: 2007, Geomagnectic Storms, in Handbook of the Solar Terrestrial
Environment, Springer Verlag, 355.
Kane, R.P.: 2005, J. Geophys. Res. 110, A02213.
Vázquez et al.
Karavaev, Yu.A., Sapronova, L.A., Bazarzhapov, A.D., Saifudinova, T.I., Kuz’minykh, Yu.V.:
2009, Geomag. Aeron. 49, 961.
Karoff, C., Inceoglu,F., Knudsen, M.F.,Olsen, J., Fogtmann-Schultz, A.: 2015, Astron.
Astrophys. 575, A77.
Kassner, C.: 1941, Meteor. Zeitschrift 58, 243.
Kimpball, D.S.: 1960, Scientific Report No. 6, Geophysical Institute, University of Alaska.
Kozyra, J.U., Nagy, A.F., Slater, D.W.: 1997, Rev. Geophys. 35, 155.
Kremliovsky, M.N.: 1994, Solar Phys. 151, 351.
Krieger, A.S., Timothy, A.F., Roelof, A.C.: 1973, Solar Phys. 29, 505.
Krivský, L., Pejml, K.: 1988, Publ. Astron. Inst. Czechosl. Acad. Sci. 84.
Lario, D., Decker, R.B., Livi, S., Krimigis, S.M., Roelof, E.C.,Russell, C.T., Fry, C.D.: 2005,
J. Geophys. Res. 110, A09S11.
Lassen, K., Laursen, O.R.: 1968, Danish Visual Aurora Observations, Danish Met. Inst.
Geophysical Papers.
Lee, E.H., Ahn, Y.S., Yang, H.J.,Chen, K.Y.: 2004, Solar Phys. 224, 373.
Leftus, V.: 2000, Solar Phys. 205, 189.
Legrand, J.P., Simon, P.A.: 1987, Ann. Geophysicae 5, 161.
Link, F.: 1964, Geofysikalmi Sbornik 212, 501.
Liritzis, Y., Petropoulos, B.: 1987, Earth, Moon, and Planets 39, 75.
Lisac, I., Marki, A.: 1998, Geofizica 15, 53.
Livesey, R.L.: 1991, Journal of the British Astronomical Association 101, 233.
Lockwood, M.: 2003, J. Geophys. Res. 108, 1128.
Lockwood, M.: 2013, Living Rev. Solar Phys. 10, 4.
Lockwood, M., Owens, M.J.: 2014, Astrophys. J. 781, L7.
Loomis, E.: 1860, American J. Sci. 2nd Ser. 30, 79.
Loomis, E.: 1861, Am. J. Sci. 2nd Ser. 32, 71.
Love, J.J.: 2011, Ann. Geophysicae 29, 1365.
Lovering, J.: 1866, Mem. A. Acad. Arts Sci. 10, 9.
Lueders, F.G.T.: 1984, Publications Washburn Observatory 12, 20.
Mairan, J.J.: 1733, Traité physique et historique de lé Aurore Boréale, Paris, Impremerie
Royale.
Ma, L.H.: 2009, New Astron. 14, 173.
Maunder, E.W.: 1894, Knowledge 17, 173.
Maunder, E.W.: 1905, Mon. Not. Roy. Astron. Soc. 65, 538.
McCracken, K., Dreschhoff, G.A.M., Smart, D.F., Shea, M.A.: 2001, J. Geophys. Res. 106,
21599.
McCracken, K.: 2007, J. Geophys. Res. 112, A09106.
McCracken, K., Beer, J., Steinhilber, F., Abreu, J.: 2013a, Solar Phys. 286, 609.
McCracken, K., Beer, J., Steinhilber, F., Abreu, J.: 2013b, Space Sci. Rev. 176, 59.
McCracken, K., Beer, J.: 2014, J. Geophys. Res. 119, 2379.
Mende, S.B., Harris, S.B., Frey, H.V., Angelopoulos, V., Russell, C.T., Donovan, E., Jacker,
B., Greffen, M., Peticola, L.M.: 2008, Spa. Sci. Rev. 141, 357.
Mikhalev, A.V., Beletsky, A.B., Kostyleva, N.V., Chernigovskaya, M.A.: 2004, Cosmic Res.
42, 591.
Milan, S.E., Hutchinson, J., Boakes, P.D., Hubert, B.: 2009, Ann. Geophys. 27, 2913.
Milton, E.R.: 1962, J. R. Astron. Soc. Canada 56, 210.
Milton, E.R.: 1969, J. R. Astron. Soc. Canada 63, 238.
Moss, K., Stauning, P.: 2012, History of Geo- and Space Sciences 3, 53.
Mouradian, Z.: 2013, Solar Phys. 282, 553.
N/A: 1902, Publications of West Hendon House Observatory, Sunderland 2, 109-119. New
Edition 2010, University of Michigan Library.
Nakazawa, Y., Okada, T., Shiokawa, K.: 2004, Earth, Planets and Space 56, e41.
Ribes, J. C., & Nesme-Ribes, E.: 1993, Astron. Astrophys. 276, 549.
Nevanlinna, H., Kataja, E.: 1993, Geophys. Res. Lett. 20, 2703.
Nevanlinna, H., Pulkkinen, T.I.: 2001, J. Geophys. Res. 106, 8109.
Odenwald, S.: 2007, Space Weather 5, S11005.
Ogurtsov, M.G., Nagovitsyn, Y.A., Kocharov, G.E., Jungner, H.: 2002, Solar Phys. 211, 371.
Oguti, T., Egeland, A.: 1995, J. Geomagn. Geoelectr. 47, 353.
Owens, M.J., Lockwood, M.: 2012, J. Geophys. Res. 117, A04102.
Owens, M.J., Usoskin, I.G., Lockwood, M.: 2012, Geophys. Res. Lett. 39, L19102.
Owens, M.J., Forsyth, R.J.: 2013, Living Reviews In Solar Physics 10, No. 5.
Aurora Borealis
Pavón-Carrasco, F.J., Tema, E., Osete, M.L., Lanza, R.: 2014, Pure and Applied Geophysics,
in press.
Pipin, V.V.: 2014, Astron. Astrophys. 346, 295.
Peristykh, A.N., Damon, P.E.: 2003, J. Geophys. Res. 108, 1003.
Raspopov, O.M., Kuz’min, I.A., Kharin, E.P.: 2007 Geomagnetism and Aeronomy, 47, 1.
Rassoul, H. K., Rohrbaugh, R.P., Tinsley, B.A., Slater, D.W.: 1993, J. Geophys. Res. 98, A5,
7695.
Réthly, A., Berkes, Z.: 1963, In Nordlicht-Beobachtungen in Ungarn, Budapest, Ungarische
Akademie der Wissenschaften.
Richardson, I.G., Cane, I.V.: 2012, Journal of Space Weather and Space Climate 2, A01.
Riley, P.: 2012, Space Weather 10, S02012.
Riley. P., Lionello, R., Linker,J.A., Cliver, E.,Balogh, A., Beer, J.,Charbonneau, P.,Crooker,
N.,DeRosa, M., Lockwood, M., Owens, M., McCracken, K., Usoskin, I., Koutchmy, S.:
2015, Astrophys. J. 802, 105.
Roach, F.E., Moore, J.G., Bruner, E.C., Cronin, H., Silverman, S.M.: 1960, J. Geophys. Res.
65, 3575.
Robbrecht, E., Berghmans, D., Van der Linden, R.A.M.: 2009 Astrophys. J. 691, 1222.
Rubenson, R.: 1882, Catalogue des aurores boréales observées en Suède, Kl. Sven. Vetenskapsakad. Handl. 18, 1-300.
Saiz, E., Cerrato, Y., Cid, C., Dobrica, Y., Hejda, P., Nenovski, P.,Stauning, P., Bochnicek,
P., Danov, D.,Demetruscu, C., Gonzalez, W.D., Maris, G., Teodisev,D.,Valach,F.: 2013
Journal of Space Weather and Space Climate 3, A26.
Salabert, D., Garcı́a, R.A.,Pallé, P.L., Jiménez, A.: 2011 Journal of Physics: Conference Series
271, 012030.
Schlamminger: 1990, Mon. Not. Roy. Astron. Soc. 247, 76.
Schove, D.J.: 1955, J. Geophys. Res. 60, 127.
Schröder, W.: 1966, Gerl. Beitr. Geophys. 75, 436.
Schröder, W.: 1988, Nature 335, 676.
Schröder, W.: 2010, History of Geo and Space Sciences 1, 45.
Schröder, W., Shefov, N.N., Treder, H.J.: 2004, Ann. Geophysicae 22, 2273.
Schwabe, H.: 1844, Astronomische Nachrichten 21, 233.
Sheeley, N.R., Howard, R.A.: 1980, Solar Phys. 67, 189.
Shiokawa, K., Ogawa, T., Kamide, Y.: 2005, J. Geophys. Res. 110, A05202.
Shirochkov, A.V., Makarova, L.N., Nikolaeva, V.D., Kotikov, A.L.: 2015, Adv. Spa. Res. 55,
211.
Silverman, S.M., Blanchard, D.C.: 1983, Planet. Spa. Sci. 31, 1131.
Silverman, S.: 1992, Rev. Geophys. 30, 333.
Silverman, S.: 1995, J. Atmos. Solar-Terr. Phys. 57, 673.
Silverman, S.: 2003, J. Geophys. Res. 108, 8011.
Silverman, S.: 2006, Adv. Spa. Res. 38, 136.
Silverman, S.: 2008, J. Atmos. Solar-Terr. Phys. 70, 1301.
Silverman, S., Cliver, E.W.: 2001, J. Atmos. Solar-Terr. Phys. 63, 523.
Singh, A.K., Sinha, A.K., Rawat, R., Jayashree, B., Pathan, B.M., Dhar, A.: 2012, Adv. Spa.
Res. 50, 1512.
Siscoe, G.L.: 1980, Rev. Geophys. 18, 647.
Sokoloff, D.: 2004, Solar Phys. 224, 145.
Solanki, S., Schüssler, M., Fligge, M.: 2000, Nature 408, 445.
Solanki, S., Schüssler, M., Fligge, M.: 2002, Astron. Astrophys. 383, 706.
Spörer, G.: 1889, Nova Acta der Ksl. Leopold Carol. deutschen Akademie der Naturforscher
53, 283.
Srivastava, N., Mathew, S.K., Louis, R.E., Wiegelmann, T.: 2009, J. Geophys. Res. 114,
A03107.
Stauning, P.: 2011, Hist. Geo. Space Sciences 2, 1.
Stetson, H.T., Brooks, C.F.: 1942, J. Geophys. Res. 47, 21.
Suess, H.E.: 1980, Radiocarbon 22, 200.
Taylor, C.J.: 1981, Artic 34, 376.
Thordarson, T., Self, S.: 2003, J. Geophys. Res. 108, 4011.
Tinsley, B.A., Rohrbaugh, R., Rassoul, H., Sahai, Y., Teixeira, N.R., Slater, D.: 1986, J.
Geophys. Res. 91, 11257.
Traversi, R., Usoskin, I.G., Solanki, S.K., Becagli, S., Frezzotti, M.,Severi, M.,Stenni, B., Udisti,
R.: 2010, Solar Phys. 280, 237.
Vázquez et al.
Trigo, R.M., Vaquero, J.M., Stothers, R.B.: 2010, Climatic Change 99, 535.
Tromholt, S.: 1898, Catalogue der in Norwegen bis Juni 1872 beobachteter Nordlichter, Jacob
Dybwad Forlag, Oslo.
Tsurutani, B.T., Gonzalez, W.D., Kamide, Y., Arballo, J.K. (Eds): 1997, AGU Geophysical
Monographs, 98, 266.
Uberoi, C.: 2011, Spa. Weather, 9, S08005.
Usoskin, I.G., Mursula, K., Kovaltsov, G.A.: 2001, J. Geophys. Res., 106, 16039.
Usoskin, I.G., Mursula, K., Solanki, S.K., Schüssler, M., Kovaltsov, G.A.: 2002, J. Geophys.
Res. 107, 1374.
Usoskin, I.G., Mursula, K., Kovaltsov, G.A.: 2003, Solar Phys. 218, 295.
Usoskin, I.G., Mursula, K., Solanki, S.K., Schüssler, M., Alanko, K.: 2004, Astron. Astrophys.
413, 745.
Usoskin, I. G., Solanki, S. K., Kovaltsov, G. A.: 2007, Astron. Astrophys. 471, 301.
Usoskin, I.G., Mursula, K., Arlt, R., Kovaltsov, G.A.: 2009, Astrophys. J. 700, L154.
Usoskin, I.G.: 2013, Living Reviews in Solar Physics 10, 1.
Usoskin, I.G., Arlt, R., Asvestari, E., Hawkins, E., Kapyla, M., Kovaltsov, G.A., Krivova, N.,
Lockwood, M., Mursula, K., O’Reilly, J., Owens, M., Scott, C.J., Sokoloff, D.D., Solanki,
S.M., Soon, W., Vaquero, J.M.: 2015, Astron. Astrophys. 581, A95.
Vallance Jones, A.: 1992, Can. J. Phys. 70, 479.
Vaquero, J. M., Gallego, M.C., Garcia, J.A.: 2003, J. Atmos. Solar-Terr. Phys. 65, 677.
Vaquero, J. M., Trigo, R.M.: 2005, Solar Phys. 231, 157.
Vaquero, J. M., Trigo, R., Gallego, M.C.: 2007, Earth, Planets, Space 59, e49.
Vaquero, J.M., Vázquez, M.: 2009, The Sun recorded through History, Springer.
Vaquero, J.M., Gallego, M.C., Barriendos, M., Rama, E., Sánchez Lorenzo, A.: 2010, Adv.
Spa. Res. 45, 1388.
Vaquero, J.M., Gallego, M.C., Usoskin, I.G., Kovaltsov, G.A.: 2011, Astrophys. J. Lett. 731,
L24.
Vaquero, J. M., Gallego, M.C., Dominguez-Castro, F.: 2013, Geofı́sica Internacional 52, 87.
Vaquero, J.M., Kovaltsov, G.A., Usoskin, I.G., Carrasco, V.M.S., Gallego, M.C.: 2015, Astron.
Astrophys. 577, A71.
Vaquero, J.M., Nogales, J.M., Sánchez-Bajo, F.: 2015, Adv. Spa. Res. 55, 1546.
Vázquez, M., Vaquero, J.M.: 2010, Solar Phys. 267, 431.
Vázquez, M., Vaquero, J.M., Curto, J.J.: 2006, Solar Phys. 238, 405.
Vázquez, M., Vaquero, J.M., Gallego, M.C.: 2014, Solar Phys. 289, 1843.
Verbanac, S., Vrsnak,B., Veronig, A., Temmer, M.: 2011, Astron. Astrophys. 526, A20.
Vestine, E.H.: 1944, Terrestrial Magnetism and Atmospheric Electricity 49, 77.
Visser, S.W.: 1942, Catalogue of Dutch Aurorae 1728 – 1940. Available from Jack Eddy’s
Compilation of Auroral Observation catalogues (rda.ucar.edu/datasets/ds836.0).
Webb, D.F., Howard, R.A.: 1994, J. Geophys. Res. 99, 4201.
Willis, D.M., Armstrong, G.M., Ault, C.E., Stephenson, F.R.: 2005, Ann. Geophysicae 23,
945.
Willis, D.M., Davis, C.J.: 2015, Evidence for recurrent auroral activity in the twelfth and
seventeenth centuries, in New Insights from recent Studies in Historical Astronomy, ASSP
Vol. 43, 61.
Willis, D.M., Stephenson, F.R.: 1996, Quartely Journal of the Royal Astronomical Society 37,
733.
Willis, D. M., Stephenson, F. R.: 2000, Ann. Geophys. 18, 1.
Willis, D.M., Stephenson, F.R.: 2002, Highlights of Astronomy 12, 346.
Willis, D.M., Stephenson, F.R., Fang, H.: 2007, Ann. Geophysicae 25, 417.
Willis, D.M., Henwood, R., Stephenson, F.R.: 2009, Ann. Geophysicae 27, 185.
Wolff, E.W., Bigler, M., Curran, M.A.J., Dibb, J.E., Frey, M.M., Legrand, M., McConnell,
J.R.: 2012, Geophys. Res. Lett. 39, L08503.
Xu, Z., Pankenier, W., Jiang, Y.: 2000, East Asian archaeoastronomy: historical records of
astronomical observations of China, Japan, and Korea, Earth Space Institute (ESI) book
series, vol. 5, Amsterdam: Gordon and Breach.
Yau, K.K.C., Stephenson, F.R., Willis, D.M.: 1995, A catalogue of auroral observations from
China, Korea and Japan (193 B.C. – A.D. 1770), Rutherford Appleton Lab. 82 p.
Yermolaev, Y.I., Lodkina, I.G., Nikolaeva, N.S., Yermolaev, M.Y.: 2013, J. Geophys. Res. 118,
4760.
Zhang, Z.: 1985, Journal of the British Astronomical Association 95, 05.
Zolotova, N.V., Ponyavin, D.I.: 2011, Astrophys. J. 736, 115.
Aurora Borealis
Zolotova, N.V., Ponyavin, D.I.: 2015, Astrophys. J. 800, 42.

Long-term trends and Gleissberg cycles in aurora borealis records

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