Comparison of STEREO's Farside Observations of Solar Activity and Predictions from the Global Oscillations Network Group (GONG)

Beginning February 18, 2011, the STEREO mission, for the first time, gave us an "All Sun" view of the entire corona in extreme ultraviolet (EUV) light. Here, we compare STEREO/EUVI views of solar activity on the farside to predictions of far side strong magnetic field regions from helioseismology using National Solar Observatory/ Global Oscillation Network Group (GONG) observations (see http://gong.nso.edu/data/farside/). The GONG project produces "All Sun" Carrington maps of strong magnetic field regions; farside regions with a probability of 70% or higher are labeled. We have produced "All Sun" Carrington maps of coronal magnetic activity by combining nearly simultaneous STEREO A & B EUVI data and SDO AIA data at each of the four EUVI wavelengths. We then visually determine whether or not magnetic activity is seen in the corona (as evidenced by brightening in EUV) at the locations predicted by GONG. We have analyzed all GONG farside predictions from February to June 2011. For 139 of 157 comparisons (89%), activity is observed in the corona by STEREO A or B. For 18 predictions, no activity was seen at the predicted region. Results from the analysis of the location of the false predictions relative to Earth will also be presented.