A comparison of two different techniques for deriving the quiet day curve from SARINET riometer data

Abstract. In this work, an upgrade of the technique for estimating the Quiet Day Curve (QDC) as proposed by Tanaka et al. (2007) is suggested. To validate our approach, the QDC is estimated from data acquired by the Imaging Riometer for Ionospheric Studies (IRIS) installed at the Southern Space Observatory (SSO/CRS/CCR/INPE – MCT, 29°4´ S, 53°8´ W, 480 m a.s.l.), São Martinho da Serra – Brazil. The evaluation was performed by comparing the difference between the QDCs derived using our upgrade technique with the one proposed by Tanaka et al. (2007). The results are discussed in terms of the seasonal variability and the level of magnetic disturbance. Also, the cosmic noise absorption (CNA) images for IRIS data operated at SSO was built using both the techniques aiming to check the implications of the changes in the methods of QDC determination on the CNA that resulted from it.