On the success rate of the farside seismic imaging of active regions

摘要

Seismic maps of the nonvisible side of the Sun (farside) have been used for almost a decade to follow large active regions before they rotate to face the Earth. Preliminary efforts to quantify the success rate of the technique (seismic holography) have been published with Michelson Doppler Imager (MDI) data. In this paper we present a thorough statistical analysis of 3 complete years of farside seismic maps (2003–2005) calculated using both Global Oscillation Network Group (GONG) data and a combined set of GONG and MDI data. A comparison with NOAA data of the frontside of the Sun during the same period shows that seismic maps detect about 40% of the total active regions that appear at the east limb of the Sun with a confidence level higher than 60%. The relationship found during this work between the seismic signature and the confidence level allows us to automatically highlight candidates in the farside seismic maps and to assign them the corresponding probability of appearance on the frontside.