J/A+A/599/A131 Butterfly diagram wings (Leussu+, 2017)
Wings of the butterfly: Sunspot groups for 1826-2015.
Leussu R., Usoskin I.G., Senthamizh Pavai V., Diercke A., Arlt R.,
Mursula K.
<Astron. Astrophys. 599, A131 (2017)>
=2017A&A...599A.131L 2017A&A...599A.131L (SIMBAD/NED BibCode)
ADC_Keywords: Sun
Keywords: Sun: activity - sunspots - history and philosophy of astronomy
Abstract:
The continuous spatio-temporal evolution (the so-called 'Maunder
butterfly diagram') of sunspot activity was available since 1874 using
data from the Royal Greenwich Observatory since 1875, extended by SOON
network data after 1976. Here we present a new extended butterfly
diagram of sunspot group occurrence continuously since 1826, using the
recently digitized data from Schwabe (1826-1867) and Spoerer
(1868-1874). The wings of the diagram are separated using a recently
developed method based on long gaps in sunspot group occurrence in
different latitude bands. Characteristic latitudes, corresponding to
the start, end and the latitudinal span of the wings, F-, L- and
H-latitudes, respectively, as well as times and asymmetries of the
butterfly wings are analyzed. The F-latitude depict a weak tendency,
especially in the S-hemisphere, to follow the wing strength
(quantified in the total sum of monthly numbers of sunspot groups).
The H-latitudes are highly significantly correlated with the strength
of the wings during cycles 12-23. The L-latitudes show no clear
relation to the wing strength. Overall, stronger cycle wings tend to
start at higher latitudes and have greater wing's span. A strong
(5-6)-cycle periodic oscillation was found in many latitudinal
parameters, such as dates of the start and end of the wings and, most
pronounced, in the difference between the wing lengths in the two
hemispheres. A barely significant oscillation of about 10 cycles
period is found in the asymmetry of the L-latitudes. The new long
database of butterfly wings and the results based on it provide new
observational constraints to the spatio-temporal distribution of
sunspot occurrence and their solar cycle related time-latitude
evolution.
Description:
fig1data.dat contains the separated wings in a butterfly diagram for
sunspot groups from three different origins: Sunspot observations by
S.H. Schwabe and G. Spoerer, and the RGO/SOON compilation. The
latitudes for sunspot groups from the Schwabe and Spoerer data are
given as size-weighted averages from sunspots belonging to each group.
Latitudes for the RGO compilation are given as they are stated in the
original data. The columns report the year, month, day, date [yr],
latitude [deg], cycle, hemisphere, and data set tag. Northern
hemisphere wings are tagged with "1" and southern hemisphere wings
with "2". The data set tag is "1" for Schwabe data, "2" for Spoerer
data and "3" for RGO data.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
fig1data.dat 32 52804 Butterfly diagram wings for solar cycles 7-24
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See also:
VI/138 : Sunspots catalogues, 1853-1870 (Casas+, 2013)
Byte-by-byte Description of file: fig1data.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "date" Obs.Date Observation date
12- 19 F8.3 yr Date Date in fractions of year
21- 25 F5.1 deg LAT Latitude, negative for southern hemisphere
27- 28 I2 --- C [7/24] Cycle number (7-24)
30 I1 --- W [1/2] Hemisphere (1: north, 2: south)
32 I1 --- D [1/3] Data set (1: Schwabe, 2: Spoerer, 3: RGO)
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Acknowledgements:
Ilya Usoskin, ilya.usoskin(at)oulu.fi
(End) Patricia Vannier [CDS] 12-Dec-2016