000003019 001__ 3019
000003019 005__ 20170106121048.0
000003019 037__ $$aPOSTER-2017-0001
000003019 100__ $$aLefèvre, Laure
000003019 245__ $$aUncertainties in the Sunspot Number
000003019 260__ $$c2016
000003019 269__ $$c2016-04-04
000003019 520__ $$aThe International Sunspot Number recently underwent an extensive makeover. In this context, a first estimation of the error bars related to this well-known measurement of solar activity was added.  Uncertainties can belong to different categories. Accuracy (differences in absolute calibration and instrument bias) and stability ,(associated with long-term drifts), are taken care of by the k-factors, and are not in the scope of this study. We focus on the effect of random errors, which are usually associated with precision and repeatability, namely how close independent measurements are when made under identical conditions.  These random errors can be inferred from a time series analysis of sunspot number records, we call these time domain errors, and they are mostly related to the precision. A second type of error arises when comparing different observers, and considering their dispersion. Here we study their comparative behaviours to understand where they stem from and how to infer them. Around solar maximum, it seems it is not the Sun that is dominating the uncertainties, but observational errors. At first glance we could say that for high sunspot numbers, the grouping of different active regions between observers might create this bias. As it turns out, the number of spots presents the most similarities with the level of uncertainties: the ability of observers to count all the spots is put to the test during high activity phases.
000003019 594__ $$aSTCE
000003019 700__ $$aDudok de With, Thierry
000003019 700__ $$aClette, Frédéric
000003019 773__ $$tSpace Climate 6 Levi Finland
000003019 8560_ $$flaure.lefevre@observatoire.be
000003019 980__ $$aCPOSTER