The well-known solar cycle controls almost the entire appearance of the solar photosphere. We therefore presume that the continuous emission of visible light from the solar surface follows the solar cyclic variation. In this study, we examine the solar cyclic variation of photospheric brightness in the visible range using solar images taken by the Solar and Heliospheric Observatory (SOHO)/Michelson Doppler Imager (MDI). The photospheric brightness in the visible range is quantified via the relative intensity acquired from in the raw solar images. In contrast to total solar irradiance, the relative intensity is out of phase with the solar cycle. During the solar minimum of solar cycles 23--24, the relative intensity shows enhanced heliolatitudinal asymmetry due to a positive asymmetry of the sunspot number. This result can be explained by the strength of the solar magnetic field that controls the strength of convection, implying that the emission in the visible range is controlled by the strength of convection. This agrees with the photospheric brightness increasing during a period of long spotless days.

Abstract
1. INTRODUCTION
2. DATA AND METHODS
3. RESULTS
    3.1. Heliolatitudinal Asymmetry of Relative Intensity
    3.2. Comparison with SORCE Spectral Irradiance
    3.3. Relationship between Absolute Solar MeanMagnetic Field and Relative Intensity
4. DISCUSSION AND SUMMARY
REFERENCES

• Dong-Gwon Jeong(Department of Earth Science Education, Chonnam National University)
• Hyungmin Park(National Youth Space Center)
• Byeongha Moon(Department of Earth Science Education, Chonnam National University)
• Suyeon Oh(Department of Earth Science Education, Chonnam National University) Corresponding author