000005295 001__ 5295
000005295 005__ 20210212155414.0
000005295 0247_ $$2DOI$$ahttps://doi.org/10.1051/swsc/2020070
000005295 037__ $$aSCART-2021-0070
000005295 100__ $$aHinrichs, Johannes
000005295 245__ $$aAnalysis of signal to noise ratio in coronagraph observations of coronal mass ejections
000005295 260__ $$c2021
000005295 520__ $$aWe establish a baseline signal-to-noise ratio (SNR) requirement for the European Space Agency (ESA)-funded Solar Coronagraph for OPErations (SCOPE) instrument in its field of view of 2.5–30 solar radii based on existing observations by the Solar and Heliospheric Observatory (SOHO). Using automatic detection of coronal mass ejections (CMEs), we anaylse the impacts when SNR deviates significantly from our previously established baseline. For our analysis, SNR values are estimated from observations made by the C3 coronagraph on the Solar and Heliospheric Observatory (SOHO) spacecraft for a number of different CMEs. Additionally, we generate a series of artificial coronagraph images, each consisting of a modelled coronal background and a CME, the latter simulated using the graduated cylindrical shell (GCS) model together with the SCRaytrace code available in the Interactive Data Language (IDL) SolarSoft library. Images are created with CME SNR levels between 0.5 and 10 at the outer edge of the field of view (FOV), generated by adding Poisson noise, and velocities between 700 km s−1 and 2800 km s−1. The images are analysed for the detectability of the CME above the noise with the automatic CME detection tool CACTus. We find in the analysed C3 images that CMEs near the outer edge of the field of view are typically 2% of the total brightness and have an SNR between 1 and 4 at their leading edge. An SNR of 4 is defined as the baseline SNR for SCOPE. The automated detection of CMEs in our simulated images by CACTus succeeded well down to SNR = 1 and for CME velocities up to 1400 km s−1. At lower SNR and higher velocity of ≥ 2100 km s−1 the detection started to break down. For SCOPE, the results from the two approaches confirm that the initial design goal of SNR = 4 would, if achieved, deliver a comparable performance to established data used in operations today, with a more compact instrument design, and a margin in SNR before existing automatic detection produces significant false positives.
000005295 594__ $$aSTCE
000005295 6531_ $$aspace weather
000005295 6531_ $$acoronagraph
000005295 6531_ $$ainstrumentation
000005295 6531_ $$asignal-to-noise
000005295 6531_ $$aSCOPE
000005295 700__ $$aDavies, Jackie A.
000005295 700__ $$aWest, Matthew J.
000005295 700__ $$aBothmer, Volker
000005295 700__ $$aBourgoignie, Bram
000005295 700__ $$aEyles, Chris J.
000005295 700__ $$aHuke, Philipp
000005295 700__ $$aJiggens, Piers
000005295 700__ $$aNicula, Bogdan
000005295 700__ $$aTappin, James
000005295 773__ $$c11$$pJournal of Space Weather and Space Climate$$v11$$y2021
000005295 8560_ $$fbogdan.nicula@observatoire.be
000005295 85642 $$ahttps://www.swsc-journal.org/articles/swsc/full_html/2021/01/swsc200025/swsc200025.html
000005295 8564_ $$s4161127$$uhttp://publi2-as.oma.be/record/5295/files/swsc200025.pdf
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000005295 905__ $$apublished in
000005295 980__ $$aREFERD