摘要：In this paper we presented two typical global 6-day planetary wave oscillations occurring in sporadic E layers. By analyzing the f o E s time series observed from several ionosonde stations on the basis of the methods suggested by Haldoupis and Pancheva (2002), we computed estimates for the PW propagation direction, zonal wave number and phase velocity. We obtained results that the 6-day PW, with zonal wave number about 1, propagates westward, which are in agreement with those reported from radar and satellite neutral wind MLT measurements. The results provide experimental evidence for a close relationship between PWs and midlatitude E s . In addition, the study proves the validity of E s observations measured routinely and rather reliably with a dense global network of digital ionosondes used as an alternative means of studying large-scale neutral atmospheric dynamics in the MLT region.
关键词：Sporadic E layers ;planetary waves ;MLT dynamics
