L1 and Off Sun‐Earth Line Visible‐Light Imaging of Earth‐Directed CMEs: An Analysis of Inconsistent Observations

The efficacy of coronal mass ejection (CME) observations as a key input to space weather forecasting is explored by comparing on and off Sun-Earth line from the ESA/NASA SOHO NASA STEREO spacecraft. A comparison made CME catalogues based L1 coronagraph imagery heliospheric imager (HI) observations, for year 2011. Analysis reveals inconsistencies in identification number potentially Earth-directed CMEs. reflect our ability identify characterise CMEs, so any discrepancies can impact prediction We show that 15 which were observed STEREO, had estimated directions compatible with events, no identified halo/partial halo counterpart listed catalogue. In-situ data confirms 9 these there was consistent Interplanetary (ICME). such "discrepant" events significant compared ICMEs recorded at 2011, stressing need address monitoring capabilities, particularly inclusion observation. While study provides evidence some CMEs are simply not visible near-Earth imagery, viewed compromised preceding remnants or presence multiple-CMEs. This underlines (1) value multiple vantage point observation, (2) benefit platform imaging, efficient tracking events.