Abstract
Physical understanding of total and spectral solar irradiance variation depends upon establishing a connection between the temporal variability of spatially resolved solar structures and spacecraft observations of irradiance. One difficulty in comparing models derived from different data sets is that the many ways for identifying solar features such as faculae, sunspots, quiet Sun, and various types of “network” are not necessarily consistent. To learn more about classification differences and how they affect irradiance models, feature “masks” are compared as derived from five current methods: multidimensional histogram analysis of NASA/National Solar Observatory/Kitt Peak spectromagnetograph data, statistical pattern recognition applied to SOHO/Michelson Doppler Imager photograms and magnetograms, threshold masks allowing for influence of spatial surroundings applied to NSO magnetograms, and “one-trigger” and “three-trigger” algorithms applied to California State University at Northridge Cartesian Full Disk Telescope intensity observations. In general all of the methods point to the same areas of the Sun for labeling sunspots and active-region faculae, and available time series of area measurements from the methods correlate well with each other and with solar irradiance. However, some methods include larger label sets, and there are important differences in detail, with measurements of sunspot area differing by as much as a factor of two. The methods differ substantially regarding inclusion of fine spatial scale in the feature definitions. The implications of these differences for modeling solar irradiance variation are discussed.
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Berger, T.E., Rouppe van der Voort, L., Lofdahl, M.G.: 2005, High resolution magnetogram measurements of solar faculae. In: AGU Spring Meeting Abstracts, SP31 – A02.
Chapman, G.A., Cookson, A.M., Dobias, J.J.: 1996, Variations in total solar irradiance during solar cycle 22. J. Geophys. Res. 101, 13541 – 13548. doi:10.1029/96JA00683.
Chapman, G.A., Cookson, A.M., Dobias, J.J.: 1997, Solar variability and the relation of facular to sunspot areas during solar cycle 22. Astrophys. J. 482, 541 – 545. doi:10.1086/304138.
Chapman, G.A., Herzog, A.D., Lawrence, J.K., Walton, S.R., Hudson, H.S., Fisher, B.M.: 1992, Precise ground-based solar photometry and variations of total irradiance. J. Geophys. Res. 97, 8211 – 8219.
Cohen, J.: 1960, A coefficient of agreement for nominal scales. Educ. Psychol. Meas. 20, 37 – 46.
de Toma, G., White, O.R., Chapman, G.A., Walton, S.R., Preminger, D.G., Cookson, A.M., Harvey, K.L.: 2001, Differences in the Sun’s radiative output in cycles 22 and 23. Astrophys. J. 549, L131 – L134. doi:10.1086/319127.
de Toma, G., White, O.R., Chapman, G.A., Walton, S.R., Preminger, D.G., Cookson, A.M.: 2004, Solar cycle 23: an anomalous cycle? Astrophys. J. 609, 1140 – 1152. doi:10.1086/421104.
Fligge, M., Solanki, S.K.: 2000, The solar spectral irradiance since 1700. Geophys. Res. Lett. 27, 2157 – 2160. doi:10.1029/2000GL000067.
Fligge, M., Solanki, S.K., Unruh, Y.C.: 2000, Modelling irradiance variations from the surface distribution of the solar magnetic field. Astron. Astrophys. 353, 380 – 388.
Foukal, P., Lean, J.: 1988, Magnetic modulation of solar luminosity by photospheric activity. Astrophys. J. 328, 347 – 357. doi:10.1086/166297.
Foukal, P., Bernasconi, P., Eaton, H., Rust, D.: 2004, Broadband measurements of facular photometric contrast using the solar bolometric imager. Astrophys. J. 611, L57 – L60. doi:10.1086/423787.
Fröhlich, C.: 2006, Solar irradiance variability since 1978. Space Sci. Rev. 125, 53 – 65. doi:10.1007/s11214-006-9046-5.
Fröhlich, C., Lean, J.: 1998, The Sun’s total irradiance: cycles, trends and related climate change uncertainties since 1976. Geophys. Res. Lett. 25, 4377 – 4380. doi:10.1029/1998GL900157.
Harvey, K.L., White, O.R.: 1999, Magnetic and radiative variability of solar surface structures. I. Image decomposition and magnetic-intensity mapping. Astrophys. J. 515, 812 – 831. doi:10.1086/307035.
Hoyt, D.V., Schatten, K.H.: 1993, A discussion of plausible solar irradiance variations, 1700 – 1992. J. Geophys. Res. 98, 18895 – 18906.
Jones, H.P., Branston, D.D., Jones, P.B., Wills-Davey, M.J.: 2000, Analysis of NASA/NSO spectromagnetograph observations for comparison with solar irradiance variations. Astrophys. J. 529, 1070 – 1083. doi:10.1086/308315.
Jones, H.P., Branston, D.D., Jones, P.B., Popescu, M.D.: 2003, Comparison of total solar irradiance with NASA/National Solar Observatory spectromagnetograph data in solar cycles 22 and 23. Astrophys. J. 589, 658 – 664. doi:10.1086/374413.
Keller, C.U., Schüssler, M., Vögler, A., Zakharov, V.: 2004, On the origin of solar faculae. Astrophys. J. 607, L59 – L62. doi:10.1086/421553.
Krivova, N.A., Solanki, S.K., Fligge, M., Unruh, Y.C.: 2003, Reconstruction of solar irradiance variations in cycle 23: is solar surface magnetism the cause? Astron. Astrophys. 399, L1 – L4. doi:10.1051/0004-6361:20030029.
Lean, J.: 2001, The variability of the Sun: from the visible to the X-rays (CD-ROM directory: contribs/lean). In: Garcia Lopez, R.J., Rebolo, R., Zapaterio Osorio, M.R. (eds.) 11th Cambridge Workshop on Cool Stars, Stellar Systems and the Sun, ASP 223, Astron. Soc. Pac., San Francisco, 109 – 116.
Lean, J., Beer, J., Bradley, R.: 1995, Reconstruction of solar irradiance since 1610: implications for climate change. Geophys. Res. Lett. 22, 3195 – 3198. doi:10.1029/95GL03093.
Lean, J., Rottman, G., Harder, J., Kopp, G.: 2005, SORCE contributions to new understanding of global change and solar variability. Solar Phys. 230, 27 – 53. doi:10.1007/s11207-005-1527-2.
Pap, J.M.: 2003, Total solar and spectral irradiance variations from near-UV to infrared. In: Rozelot, J.P. (ed.) The Sun’s Surface and Subsurface: Investigating Shape, Lecture Notes in Physics 599, Springer, Berlin, 129 – 155.
Pap, J.M., Turmon, M., Floyd, L., Fröhlich, C., Wehrli, C.: 2002, Total solar and spectral irradiance variations from solar cycles 21 to 23. Adv. Space Res. 29, 1923 – 1932.
Preminger, D.G., Walton, S.R., Chapman, G.A.: 2001, Solar feature identification using contrasts and contiguity. Solar Phys. 202, 53 – 62.
Preminger, D.G., Walton, S.R., Chapman, G.A.: 2002, Photometric quantities for solar irradiance modeling. J. Geophys. Res. 107, 1354 – 1362. doi:10.1029/2001JA009169.
Turmon, M., Pap, J.M., Mukhtar, S.: 2002, Statistical pattern recognition for labeling solar active regions: application to SOHO/MDI imagery. Astrophys. J. 568, 396 – 407. doi:10.1086/338681.
Wenzler, T., Solanki, S.K., Krivova, N.A., Fröhlich, C.: 2006, Reconstruction of solar irradiance variations in cycles 21 – 23 based on surface magnetic fields. Astron. Astrophys. 460, 583 – 595. doi:10.1051/0004-6361:20065752.
Willson, R.C., Hudson, H.S.: 1988, Solar luminosity variations in solar cycle 21. Nature 332, 810 – 812. doi:10.1038/332810a0.
Willson, R.C., Mordvinov, A.V.: 2003, Secular total solar irradiance trend during solar cycles 21 – 23. Geophys. Res. Lett. 30, 1199 – 1202.
Willson, R.C., Gulkis, S., Janssen, M., Hudson, H.S., Chapman, G.A.: 1981, Observations of solar irradiance variability. Science 211, 700 – 702.
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K.L. Harvey and S.R. Walton are deseased, to whom this paper is dedicated.
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Jones, H.P., Chapman, G.A., Harvey, K.L. et al. A Comparison of Feature Classification Methods for Modeling Solar Irradiance Variation. Sol Phys 248, 323–337 (2008). https://doi.org/10.1007/s11207-007-9069-4
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DOI: https://doi.org/10.1007/s11207-007-9069-4