赤道附近局地激发LS-TAD的事例观测

大尺度行进式大气扰动(LS-TAD)通常被认为起源于极区高纬,本文报道了一起激发于低纬赤道地区、在北半球向高纬传播的LS-TAD观测事例.2002年8月10日07:30 UT,CHAMP卫星在30°W磁赤道附近观测到显著的大气密度增强,在随后的2个连续轨道上,该密度增强依次出现在北半球更高纬度上,表现出明显的极向位移,...

A case study of large-scale travelling atmospheric disturbances driven by equatorial local source

Large-Scale Travelling Atmospheric Disturbance(LS-TAD)is generally believed to originate from the high-latitude auroral areas and then propagate equatorward.In this paper,we report a case of LS-TAD which was stimulated in low-latitude equatorial regions and propagated toward higher latitudes in the Northern hemisphere.CHAMP spacecraft encountered a remarkable neutral density enhancement at equatorial region during its flight over South America about 07∶30 UT on 10^th Aug.2002.The density enhancements were detected during the following 3 flyovers at higher latitude in the Northern Hemisphere.Remarkable latitudinal displacement of the density enhancement suggests presence of a LS-TAD.Meanwhile,evidences of Large-Scale Travelling Ionospheric Disturbance(LS-TID),which is generally accompanied by LS-TAD,was recorded by two ground-based GNSS chains.We find no signatures of travelling disturbances in Southern Hemisphere,which are related to the aforementioned LS-TAD/TID.We suggest that the observed LS-TAD was likely to originate from equatorial region,driven by an abrupt increasement of ion vertical drift.