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Inverse projection method for determination of distribution of real CME latitudes applied to the 1997–1998 SOHO LASCO observations
Author(s) -
Skirgiello Marta
Publication year - 2003
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2003gl017618
Subject(s) - latitude , sky , projection (relational algebra) , geodesy , geographic coordinate system , coronal mass ejection , remote sensing , geology , physics , meteorology , solar wind , computer science , algorithm , plasma , quantum mechanics
Coronograph observations of coronal mass ejections (CMEs) do not provide the real latitude of their origin. The registered apparent latitude is the projection of the CME trajectory on the plane of the sky, and it may considerably differ from their original location. We show in this paper, how the projection effects can be eliminated from CME latitude distribution. The proposed method is based on the assumption that events move radially, their longitudinal distribution is uniform, and they are all detected. This tool has been applied to SOHO LASCO data, for which detection efficiency was near 100%. The obtained distributions of real latitudes have cut off at ∼20° in 1997 (minimum solar activity) and ∼50° in 1998 (rise phase). The events observed at higher latitudes proved to be only apparent projections of events really originated at lower latitudes.