TY - JOUR
T1 - Temporal variation and asymmetry of sunspot and solar plage types from 1930 to 1936
AU - Seguí, A.
AU - Curto, J. J.
AU - de Paula Vila, Victor
AU - Rodríguez-Gasén, R.
AU - Vaquero, J. M.
N1 - Publisher Copyright:
© 2019 COSPAR
PY - 2019/6/1
Y1 - 2019/6/1
N2 - Using the recently converted to digital format heliophysics catalogues of the Ebro Observatory published in the 1930s, we analyse simultaneously the temporal variation and asymmetry of two different solar structures located at different layers of the solar atmosphere: sunspots and solar plages. In particular, we do the research for all the types of sunspots and plages, including the daily and relative frequencies over the solar cycle. The data were catalogued using the sunspot Cortie classification and a solar plage classification scheme proposed by the Ebro Observatory, which group the phenomena by size and shape. For all types of both sunspots and plages, we observe a decrease in their frequency up to the end of solar cycle 16 and an increase over the beginning of solar cycle 17. Furthermore, we note that small sunspot groups are more likely to happen than bigger groups, although single big spots dominate near the solar minimum. The daily frequency of solar plage occurrences shows that there is not a dominance of compact or scattered solar plages. The North-South occurrence distribution of every type in both sunspots and solar plages shows an asymmetry during the solar cycle: in its declining phase, such asymmetry is directed to the north, while in the beginning of a new cycle is directed to the south.
AB - Using the recently converted to digital format heliophysics catalogues of the Ebro Observatory published in the 1930s, we analyse simultaneously the temporal variation and asymmetry of two different solar structures located at different layers of the solar atmosphere: sunspots and solar plages. In particular, we do the research for all the types of sunspots and plages, including the daily and relative frequencies over the solar cycle. The data were catalogued using the sunspot Cortie classification and a solar plage classification scheme proposed by the Ebro Observatory, which group the phenomena by size and shape. For all types of both sunspots and plages, we observe a decrease in their frequency up to the end of solar cycle 16 and an increase over the beginning of solar cycle 17. Furthermore, we note that small sunspot groups are more likely to happen than bigger groups, although single big spots dominate near the solar minimum. The daily frequency of solar plage occurrences shows that there is not a dominance of compact or scattered solar plages. The North-South occurrence distribution of every type in both sunspots and solar plages shows an asymmetry during the solar cycle: in its declining phase, such asymmetry is directed to the north, while in the beginning of a new cycle is directed to the south.
KW - Asymmetry
KW - Cortie classification
KW - Solar plages
KW - Sunspots
UR - http://www.scopus.com/inward/record.url?scp=85062224146&partnerID=8YFLogxK
U2 - 10.1016/j.asr.2019.02.018
DO - 10.1016/j.asr.2019.02.018
M3 - Article
AN - SCOPUS:85062224146
SN - 0273-1177
VL - 63
SP - 3738
EP - 3748
JO - Advances in Space Research
JF - Advances in Space Research
IS - 11
ER -