Research Article

Comparison of Magnesium II core-to-wing ratio observations during solar minimum 23/24

¹ Laboratory for Atmospheric and Space Physics (LASP), University of Colorado, Boulder, CO 80309, USA
² Institute of Environmental Physics, University of Bremen FB1, PO Box 330440, 28334 Bremen, Germany
³ Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado, Boulder, CO 80309, USA
⁴ National Geophysical Data Center (NGDC), National Oceanic and Atmospheric Administration, Boulder, CO 80305, USA
⁵ Space Weather Prediction Center (SWPC), National Oceanic and Atmospheric Administration, Boulder, CO 80305, USA

^* Corresponding author: e-mail: snow@lasp.colorado.edu

Received: 15 September 2013
Accepted: 5 December 2013

Abstract

The MgII index is an important proxy for solar activity; in particular it correlates well with the EUV which is important for understanding the upper atmosphere. We compare the measurements from all of the instruments making daily measurements during the most recent solar minimum. After adjustments to the data to account for instrumental effects, we find that there are still some discrepancies between the various time series. The data from the primary channel of the SOLar-STellar Irradiance Comparison Experiment (SOLSTICE) on SORCE requires a correction factor starting in early 2006 in order to bring it into agreement with the redundant SOLSTICE channel and with the other datasets. Once this correction has been applied, all the MgII measurements are in good agreement throughout the solar minimum interval.