Automatic identification and observations of blanketing sporadic E events in the equatorial region over Jicamarca

Abstract

In equatorial regions, equatorial electrojet (EEJ) echoes often overlap with blanketing sporadic E (Esb) echoes. Also, Esb events could be classified as rare events over the Jicamarca Radio Observatory (JRO). For that reason, Esb identification is a big challenge for current software. Until now, the conventional method identifies Esb echoes visually. In this work, an innovative approach for automatic identification and observation of Esb events is presented. We developed an algorithm and implemented the first software to identify Esb events using image processing techniques and machine learning algorithms getting a sensitivity of 89%. We proposed a new criterion to identify Esb events taken into account the normal tendency of the F-layer minimum frequency due mainly to absorbance of the D region. We report the results of the first statistical study of Esb occurrence over JRO (11.95° S, 76.87° W and dip angle ~1°) using the Digital Portable Sounder (DPS) - 4 Digisonde data from 2001 to 2018. We found Esb occurs mainly during the December solstice and also during minimum solar years. We observe the occurrence of Esb with a main peak at 1600 LT and a second peak around 0800 - 0900 LT. Furthermore, we obtained the ΔH between Jicamarca and Piura to measure the intensity of EEJ and counter electrojet (CEJ) and its behavior in time when Esb occurs. Finally, we discuss possible conditions that favor the formation of Esb.