Remote sensing of ionospheric plasma bubbles using GPS/GNSS

The equatorial plasma bubble (EPB) is plasma depleted region of the ionosphere which affects the trans-ionospheric communication/ navigation to great extent. In this paper occurrence and characteristic of plasma bubbles over the Hong Kong during deep solar minimum 2007-2009, has been studied using the GPS data from continuously operating reference stations (CORS) network. Generally, plasma bubble occurrence is expected to be maximum during the equinox season but for the deep solar minimum period from 2007 to 2009 unusual seasonal occurrence in plasma bubbles has been observed and found to be a maximum during the June solstice instead of equinox. The diurnal characteristics of plasma bubbles have been studied and their occurrences are found to be more prominent during the nighttime hours. Moreover, the daytime EPBs observations are also noticed but their occurrences are found to be occasional. The observed daytime plasma bubbles are expected to be generated in the post-midnight hour at higher altitude and can survive until the daytime. The latitudinal dimensions of observed plasma bubbles during 2007-2009 are found to be dominant in 200-400 km range.