Filament Disappearances During the Period of September 1991 through September 1994

摘要: Continuous full-disk Hα images recorded by the Big Bear Solar Observatory (BBSO) from 1 September 1991 to 19 1994 (the first three years of Yohkoh mission) were digitized and analyzed. The data set consists nearly 10000 images, one every half hour for period when BBSO was observing. Two statistical studies disappearing solar filaments based on this are made: (1) disk latitude distribution all larger with a minimum length 70 arc sec, including time their disappearance. Of 1095 such filaments, 439 disappeared during our continuous observations, 314 night gap, 162 gap (more than 94 hours) 180 rotated beyond west limb. If we plot latitudes as function these it shows uniform in latitude. However, if (200 sec or above), then butterfly trend appears – position tends drift lower activity decreases. (2) detectable large small, 9-months period, January 1994. We find that size 351 collected follows power law index −1.40.