Correlation between the different activity indicators and the longitudinal field | Bl |, where the dashed line represents least square fit to the data and the Pearson’s r is shown in the plot. Top left: anti-correlation between S-index and | Bl | over six epochs of observations. The bold crosses represent the mean and standard deviation as dispersion. Only the mean values are included in the fit. Top right: plot showing the correlation between S-index and Hα-index over seven epochs of observations. Bottom left: correlation between S-index and CaIRT-index over seven epochs of data. Bottom right: correlation between Hα-index and CaIRT-index over seven epochs of data.