Solar Cycle Variation of Interplanetary Coronal Mass Ejection Latitudes

With the use of interplanetary coronal mass ejections (ICMEs) compiled by Richardson and Cane from 1996 to 2007 and the associated coronal mass ejections (CMEs) observed by the Large Angle and Spectrometric Coronagraph (LASCO) onboard the Solar and Heliospheric Observatory (SOHO), we investigate the solar cycle variation of real ICME-associated CME latitudes during solar cycle 23 using Song et al.'s method. The results show the following: Although most of ICME-associated CMEs are distributed at low latitudes, there is a significant fraction of ICME-associated CMEs occurring at high latitudes. The latitudinal evolution of ICME-associated CMEs do not follow Sporer's sunspot law at low latitudes (thus, no 'butterfly diagram'); how-ever, at high latitudes, there may be a poleward motion and an equator-ward motion from the rise to the maximum to the declining phases.