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Full Record Details
Persistent URL
http://purl.org/net/epubs/work/51117
Record Status
Checked
Record Id
51117
Title
Increasing lifetime of recurrent sunspot groups within the Greenwich Photoheliographic Results
Contributors
R Henwood (STFC Rutherford Appleton Lab. & Warwick Univ.)
,
SC Chapman
,
DM Willis (STFC Rutherford Appleton Lab. & Warwick Univ.)
Abstract
Long-lived (>20 days) sunspot groups extracted from the Greenwich Photo- heliographic Results (GPR) are examined for evidence of decadal change. The problem of identifying sunspot groups which are observed on consecutive solar rotations (recurrent sunspot groups) is tackled by first constructing manually an example dataset of recurrent sunspot groups and then using machine learning to generalise this subset to the whole GPR. The resulting dataset of recurrent sunspot groups is verified against previous work by A. Maunder and other Royal Greenwich Observatory (RGO) compilers. Recurrent groups are found to exhibit a slightly larger value for the Gnevyshev-Waldmeier Relationship than the value found by Petrovay and van Driel-Gesztelyi (Solar Phys. 51, 25, 1997), who used recurrence data from the Debrecen Photoheliographic Results. Evidence for sunspot group lifetime change over the previous century is observed within recurrent groups. A lifetime increase of 1.4 between 1915 and 1940 is found, which closely agrees with results from Blanter et al. (Solar Phys. 237, 329, 2006). Furthermore, this increase is found to exist over a longer period (1915 to 1950) than previously thought and provisional evidence is found for a decline between 1950 and 1965. Possible applications of machine-learning procedures to the analysis of historical sunspot observations, the determination of the magnetic topology of the solar corona and the incidence of severe space-weather events are outlined briefly.
Organisation
SSTD
,
STFC
,
SSTD-SDD
Keywords
non-linear
,
sunspot nest
,
recurrence
,
sunspots
,
lifetime
,
Physics
,
long-term change
,
neural networks
,
sunspot nestlet
,
greenwich
Funding Information
Related Research Object(s):
Licence Information:
Language
English (EN)
Type
Details
URI(s)
Local file(s)
Year
Journal Article
Sol Phys
262, no. 2 (2009): 299-313.
doi:10.1007/s11207-009-9419-5
2009
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