Mapping of 2D sporadic E structure using high density GPS receivers in South East Asia

Abstract

Sporadic E (Es) is a cloud of intensified electron concentration that developed at the ionospheric E layer that might interrupt the pathway of radio communication. Despite the abundance of studies on Es have been carried out, equatorial Es was hardly highlighted. This investigation was executed with the intent of observing the Es events near equatorial South East Asia (SEA) region. Using well-established methods such as ionosonde and Equatorial Atmosphere Radar that set up at Kototabang, Indonesia, the E layer was simultaneously analysed to identify Es. Then, data from dense SEA Global Positioning System (GPS) network for 23rd June 2011 with measured critical frequency of Es (foEs) and virtual height of Es (hEs) provided by ionosonde dataset and Range-Time-Intensity plot were used to plot a detrended GPS Total Electron Contecnt (TEC) maps thus producing a 2-D equatorial Es map. From the TEC maps, the presence of Es frontal structure was identified with 50-500 km length and 10-30 km width and that is composed of smaller scale irregularities. Also, Es structure moves in the North-South direction, perpendicular with elongation azimuth. The findings disclose the morphology and dynamics of equatorial Es and initiate a geographically broad-scale Es observation using GPS TEC.