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Analysis and Modeling of Solar Irradiance Variations

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Analysis and Modeling of Solar Irradiance Variations Analysis and modeling of solar irradiance variations Von der Fakultät für Elektrotechnik, Informationstechnik, Physik der Technischen Universität Carolo-Wilhelmina zu Braunschweig zur Erlangung des Grades eines Doktors der Naturwissenschaften (Dr.rer.nat.) genehmigte Dissertation Kumulative Arbeit von Kok Leng Yeo arXiv:1412.3935v2 [astro-ph.SR] 5 Jul 2015 aus Singapur 1. Referentin oder Referent: Professor Dr. Sami K. Solanki 2. Referentin oder Referent: Professor Dr. Karl-Heinz Glaßmeier eingereicht am: 22 April 2014 mündliche Prüfung (Disputation) am:11 Juli 2014 (2014) Vorveröffentlichung der Dissertation Teilergebnisse aus dieser Arbeit wurden mit Genehmigung der Fakultät für Elektrotech- nik, Informationstechnik, Physik, vertreten durch den Mentor der Arbeit, in folgenden Beiträgen vorab veröffentlicht: Publikationen • Yeo, K. L., Krivova, N. A., Solanki, S. K., Glassmeier, K. H., 2014, Reconstruction of total and spectral solar irradiance since 1974 based on KPVT, SoHO/MDI and SDO/HMI observations, Astron. Astrophys., 570, A85 • Thuillier, G., Schmidtke, G., Erhardt, C., Nikutowski, B., Shapiro, A. I., Bolduc, C., Lean, J., Krivova, N. A., Charbonneau, P., Cessateur, G., Haberreiter, M., Melo, S., Delouille, V., Mampaey, B., Yeo, K. L., Schmutz, W., 2014, Solar spectral ir- radiance variability in November/December 2012: comparison of observations by instruments on the International Space Station and models, Sol. Phys., online • Yeo, K. L., Krivova, N. A., Solanki, S. K., 2014, Solar cycle variation in solar irradiance, Space Sci. Rev., online • Yeo, K. L., Feller, A., Solanki, S. K., Couvidat, S., Danilovic, S., Krivova, N. A., 2014, Point spread function of SDO/HMI and the effects of stray light correction on the apparent properties of solar surface phenomena, Astron. Astrophys., 561, A22 • Yeo, K. L., Solanki, S. K., Krivova, N. A., 2013, Intensity contrast of network and faculae, Astron. Astrophys., 550, A95 Tagungsbeiträge • Yeo, K. L., Solanki, S. K., Krivova, N. A., Solar irradiance variability and the Earth’s climate, SCOSTEP’s 13th Quadrennial Solar-Terrestrial Physics Sympo- sium, Xi’an, China, 13 to 18 October 2014 (invited talk) • Yeo, K. L., Solanki, S. K., Krivova, N. A., Model reconstruction of total and spectral solar irradiance since 1974, AOGS 11th Annual Meeting, Sapporo, Japan, 28 July to 1 August 2014 (poster) • Yeo, K. L., Krivova, N. A., Solanki, S. K., Reconstruction of TSI and SSI in the satellite era. EGU General Assembly 2014, Vienna, Austria, 27 April to 2 May 2014 (invited talk) 3 Vorveröffentlichung der Dissertation • Krivova, N. A., Yeo, K. L., Solanki, S. K., Dasi-Espuig, M., Ball, W., Modelling so- lar irradiance with SATIRE, 2014 SORCE Science Meeting, Cocoa Beach, Florida, USA, 28 to 31 January 2014 (invited talk) • Yeo, K. L., Solanki, S. K., Krivova, N. A., SATIRE-S reconstruction of total and spectral solar irradiance from 1974 to 2013, International CAWSES-II Symposium, 18 to 22 November 2013, Nagoya, Japan (poster) • Yeo, K. L., Krivova, N. A., Solanki, S. K., Cyclic variation in solar irradiance, ‘The Solar Activity Cycle: Physical Causes And Consequences’ Workshop, Bern, Switzerland, 11 to 15 November 2013 (invited talk) • Yeo, K. L., Solanki, S. K., Krivova, N. A., Network & facular contribution to solar irradiance variation, Space Climate 5, Oulu, Finland, 15 to 19 June 2013 (poster) • Yeo, K. L., Solanki, S. K., Krivova, N. A., Comparing irradiance reconstructions from HMI magnetograms with SORCE observations, 2011 SORCE Science Meet- ing, Sedona, Arizona, USA, 13 to 16 September 2011 (poster) • Yeo, K. L., Solanki, S. K., Krivova, N. A., Reconstructing total solar irradiance from HMI/SDO observations, LWS/SDO-1 Workshop, Squaw Creek, California, USA, 1 to 5 May 2011 (poster) 4 Contents Summary 9 1 Introduction 11 1.1 Measurements and models of solar irradiance . 11 1.2 SDO/HMI.................................. 15 1.3 SATIRE-S . 17 1.4 Thesis outline . 20 2 Background 23 2.1 Physical origin of solar radiation . 23 2.1.1 Energy transport in the solar interior . 23 2.1.2 Formation of the solar spectrum . 24 2.2 The 11-year activity cycle of the Sun and solar magnetism . 26 2.2.1 Solar cycle variation in solar magnetism . 27 2.2.2 The solar dynamo . 31 2.3 Solar model atmospheres and intensity spectra . 33 2.3.1 The radiative transfer equation . 34 2.3.2 Local thermodynamic equilibrium . 35 2.3.3 Line blanketing and opacity . 36 2.3.4 Three-dimensional model atmospheres . 38 3 Intensity contrast of solar network and faculae (The contents of this chapter are identical to the printed version of Yeo, K. L., Solanki, S. K., Krivova, N. A., 2013, Intensity contrast of network and faculae, Astron. Astrophys., 550, A95.) 41 3.1 Introduction . 42 3.2 Method . 44 3.2.1 SDO/HMI data . 44 3.2.2 Data reduction . 45 3.2.2.1 Magnetogram noise level . 45 3.2.2.2 Quiet Sun intensity . 46 3.2.2.3 Identification of network and faculae . 48 3.2.2.4 Definition of intensity contrast . 52 3.3 Results . 53 3.3.1 Variation with position and magnetogram signal . 53 3.3.2 Surface fits . 56 3.3.3 Intrinsic contrast . 58 5 Contents 3.4 Discussion . 61 3.4.1 Comparison with Ortiz et al. (2002) . 61 3.4.2 Continuum intensity contrast about disc centre . 66 3.4.3 Line core intensity contrast . 69 3.4.4 Facular contribution to variation in solar irradiance . 72 3.5 Conclusion . 75 4 Point spread function of SDO/HMI and the effects of stray light correction on the apparent properties of solar surface phenomena (The contents of this chapter are identical to the printed version of Yeo, K. L., Feller, A., Solanki, S. K., Couvidat, S., Danilovic, S., Krivova, N. A., 2014, Point spread function of SDO/HMI and the effects of stray light correction on the apparent properties of solar surface phenomena, Astron. Astrophys., 561, A22.) 77 4.1 Introduction . 78 4.2 PSF derivation . 80 4.2.1 Data selection . 80 4.2.2 PSF derivation method . 84 4.2.3 Image restoration method . 91 4.2.4 Interaction between solar radiation and the venusian atmosphere . 92 4.2.4.1 Diffusion and scattering of solar radiation in the venu- sian atmosphere . 92 4.2.4.2 Refraction of solar radiation in the venusian atmosphere 94 4.2.4.3 Final estimate of the PSF . 99 4.2.5 Partial lunar eclipse and solar limb observations . 100 4.3 Application of the derived PSF to HMI observations . 101 4.3.1 Granulation contrast . 101 4.3.2 Effect of image restoration on the Dopplergram, longitudinal mag- netogram, continuum intensity and line depth data products . 107 4.3.2.1 Intensity contrast and magnetogram signal of small- scale magnetic concentrations . 108 4.3.2.2 Intensity and magnetogram signal of sunspots and pores 111 4.3.2.3 Amount of magnetic flux on the solar surface . 111 4.3.2.4 Line-of-sight velocity . 116 4.4 Variation of the PSF within the FOV, between the HMI CCDs and with time119 4.4.1 Variation of the PSF with FOV position . 119 4.4.2 Variation of the PSF between the HMI CCDs and with time . 122 4.5 Summary . 124 5 Reconstruction of total and spectral solar irradiance from 1974 to 2013 based on KPVT, SoHO/MDI and SDO/HMI observations (The contents of this chapter are identical to the submitted version of Yeo, K. L., Krivova, N. A., Solanki, S. K., Glassmeier, K. H., 2014, Reconstruction of total and spectral solar irradiance from 1974 to 2013 based on KPVT, SoHO/MDI and SDO/HMI observations, Astron. Astro- phys., 570, A85.) 127 5.1 Introduction . 128 5.2 The SATIRE-S model . 130 6 Contents 5.3 Data selection and preparation . 131 5.3.1 Daily full-disc continuum intensity images and longitudinal mag- netograms . 131 5.3.1.1 HMI . 132 5.3.1.2 MDI . 132 5.3.1.3 KPVT . 134 5.3.2 TSI measurements . 136 5.4 Solar irradiance reconstruction . 137 5.4.1 Harmonizing the model input from multiple instruments . 137 5.4.1.1 Umbra and penumbra . 137 5.4.1.2 Faculae . 138 5.4.2 The free parameter . 144 5.4.3 Ultraviolet solar irradiance . 148 5.4.4 Data gaps . 153 5.4.5 Error analysis . 155 5.5 Discussion . 156 5.5.1 Comparison with observations . 156 5.5.1.1 TSI composites . 156 5.5.1.2 Solar Lyman-α irradiance and Mg II index composites . 160 5.5.1.3 UARS and SORCE ultraviolet solar irradiance . 162 5.5.1.4 SORCE/SIM SSI . 166 5.5.2 Facular and sunspot contribution to variation in TSI . 171 5.6 Summary . 173 6 Solar cycle variation in solar irradiance (The contents of this chapter are identical to the submitted version of Yeo, K. L., Krivova, N. A., Solanki, S. K., 2014, Solar cycle variation in solar irradiance, Space Sci. Rev., online.) 179 6.1 Introduction . 179 6.2 Measurements . 180 6.2.1 Total solar irradiance, TSI . 180 6.2.2 Spectral solar irradiance, SSI . 183 6.3 Models . 188 6.3.1 Solar surface magnetism . 188 6.3.2 Model architectures . 192 6.3.3 SSI models capable of returning the full solar spectrum . 194 6.3.3.1 SATIRE-S . 194 6.3.3.2 Other present-day models . 197 6.4 Reconciling measurements and models . 200 6.4.1 Proxy models . 200 6.4.2 Semi-empirical models . 201 6.5 Summary . 202 7 Summary and outlook 207 Bibliography 215 7 Contents Publications 237 Acknowledgements 239 Curriculum Vitae 241 Erklärung zum eigenen Beitrag 243 8 Summary A prominent manifestation of the solar dynamo is the 11-year activity cycle, visible in indicators of solar activity, including the topic of this thesis, solar irradiance.
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