After the daily observation, files that contain the averaged correlation value are automatically created from the raw data. This data is convenient for quick-look of the data. Definition of 'correlation' is "averaged values of correlation of antenna pairs (after removing short base-line pairs) of NoRH". Correlation increases as a strong microwave signal comes due to e.g. a flare. So it is used instead of the real light curve (plot of flux density). For 17 GHz plot, 1 % of correlation corresponds to 30 SFU flux density. It is used because much computation resource is necessary for image synthesis that is the only method to obtain flux density at each time (see section 3.5.6). And correlation has an advantage that it is almost not affected by the weather condition. However, it does not increase when the flux is so strong because it has an upper limit of unity.