Coronal Hole Detection and Open Magnetic Flux

Many scientists use coronal hole (CH) detections to infer open magnetic flux. Detection techniques differ in the areas that they assign as open, and may obtain different values for We characterize uncertainties of these methods, by applying six detection methods deduce area flux a near-disk center CH observed on 9/19/2010, single method five EUV filtergrams this CH. Open was calculated using maps. The standard deviation (interpreted uncertainty) estimate about 26%. However, including variability data sources, uncertainty almost doubles 45%. two all CHs time period. find is greatly underestimated compared inferred from in-situ measurements (by 2.2-4 times). also test our simulated emission images thermodynamic MHD model solar corona. overestimate CH, but average error only 7%. full-Sun corona underestimate flux, factors well below what needed account missing observations. Under-detection holes likely contributes recognized deficit unlikely resolve it.