Show simple item record Chapman, G. A. De Toma, G. Cookson, A. M. 2018-07-11T17:42:10Z 2018-07-11T17:42:10Z 2014
dc.identifier.citation Solar Physics 289, 3961-3967. (2014) en
dc.identifier.issn 0038-0938
dc.identifier.other 1573-093X
dc.description.abstract There has been much speculation about the extended minimum between Solar Cycles 23 and 24. Cycle 24 itself has been unusually weak compared with recent cycles. We present quantitative evidence for the weakness of both Cycles 23 and, particularly, 24. The data are objective indices derived from precision photometric images obtained on a daily basis at the San Fernando Observatory. These data form the longest running, homogeneous photometric record known to us. We show sunspot areas from red images and facular/network areas from Ca ii K-line images. Spot and facular area are a simple and direct measurement of the strength of solar activity. The data clearly show the decline in the amplitude of sunspot maxima for Cycles 23 and 24 compared with Cycle 22. The relative amplitudes of mean spot area for Cycles 22 through 24 are 1.0, 0.74, and 0.37, respectively. There is also an indication that the facular-to-spot area ratio has increased in Cycle 24. en
dc.format.extent 7 pages en
dc.publisher Springer Verlag en
dc.rights copyright The Author(s) 2014 en
dc.subject Solar cycle: observations en
dc.subject active regions en
dc.title An Observed Decline In The Amplitude Of Recent Solar-Cycle Peaks en
dc.type Article en

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