Longitudinal development of low-latitude ionospheric irregularities during the geomagnetic storms of July 2004
作者单位：National Institute of Information and Communications TechnologyKoganeiJapan Solar-Terrestrial Environment LaboratoryNagoya UniversityNagoyaJapan
会议名称：《中国科学院地质与地球物理研究所第十届(2010年度)学术年会》
会议日期：2011年
学科分类：070801[理学-固体地球物理学] 07[理学] 0708[理学-地球物理学]
基 金：supported by the Natural Science Foundation of China(40774091,40574072,40904038) National Important Basic Research Project(2006CB806306) support from NSF Cooperative Agreement ATM-0432565 through Cornell University. J.S.X. was supported by the NSF of China (40874085)
摘 要：[1]During the period 22-28 July 2004,three geomagnetic storms occurred due to a sequence of coronal mass *** this paper we present and discuss the ionospheric observations from a set of in situ satellites and ground-based GPS total electron content and scintillation receivers,a VHF radar,and two chains of ionosondes(～300°E and～120°E, respectively) that provide the evolutionary characteristics of equatorial and low-latitude ionospheric irregularities versus longitude during these storm *** is found that the irregularities occurred over a wide longitudinal range,extending from around 300°E to 120°E on storm days 25 and 27 July *** 25 July plasma bubbles(PBs) began premidnight in America and postmidnight in Southeast *** 27 July the occurrence of irregularities followed the sunset terminator and was observed sequentially after sunset from American to Southeast Asian *** studies have reported that storm-time low-latitude ionospheric irregularities are mostly confined to a narrower longitude range,90°,after sunset hours and are associated with the prompt penetration of eastward electric fields(PPEFs) into low *** June solstice months the occurrence of range-type spread F or PBs is very low in Southeast Asian and South American *** contrast,the present results indicate that geomagnetic storms triggered the wide longitudinal development of *** the American sector this was probably due to the effects of PPEFs on both storm ***,in the Southeast Asian sector the PBs on the 2 days probably arose from disturbance dynamo electric field(DDEF),PPEF,and gravity wave seeding *** study further shows that under complex storm conditions, besides the long duration or multiple penetrations,the combined effects of PPEFs and DDEFs could result in a wide longitude extent of ionospheric irregularities at times.