抚仙湖太阳观测和研究基地知识库

Solar photospheric magnetic field plays a dominant role in the variability of total solar irradiance (TSI). The modulation of magnetic flux at six specific ranges on TSI is characterized for the first time. The daily flux values of magnetic field at four ranges are extracted from MDI/SOHO, together with daily flux of active regions (MFar) and quiet regions (MFqr); the first four ranges (MF1-4) are: 1.5-2.9, 2.9-32.0, 32.0-42.7, and 42.7-380.1 (x10(18) Mx per element), respectively. Cross-correlograms show that MF4, MFqr, and MFar are positively correlated with TSI, while MF2 is negatively correlated with TSI; the correlations between MF1, MF3 and TSI are insignificant. The bootstrapping tests confirm that the impact of MF4 on TSI is more significant than that of MFar and MFqr, and MFar leads TSI by one rotational period. By extracting the rotational variations in the MFs and TSI, the modulations of the former on the latter at the solar rotational timescale are clearly illustrated and compared during solar maximum and minimum times, respectively. Comparison of the relative amplitudes of the long-term variation show that TSI is in good agreement with the variation of MF4 and MFar; besides, MF2 is in antiphase with TSI, and it lags the latter by about 1.5 years.