Performance of MIDAS Over East African Longitude Sector: Case Study During 4–14 March 2012 Quiet to Disturbed Geomagnetic Conditions

Abstract

This study investigates the performance of a tomographic algorithm, Multi‐Instrument and Data Analysis System (MIDAS), during an extended period of 4–14 March 2012, containing moderate and strong geomagnetic storms conditions, over an understudied and data scarce Eastern African longitude sector. Nonetheless, a relatively better distribution of Global Navigation Satellite Systems stations exists along a narrow longitude sector between 30°E and 44°E and latitude range of 30°S and 36°N that spans the equatorial, middle‐, and low‐latitude ionosphere. Then results are compared with independent global models such as International Reference Ionosphere 2012 (IRI‐2012) and global ionosphere map (GIM). MIDAS performance was better than that of the IRI‐2012 and GIM models in terms of capturing the diurnal trends as well as the short temporal total electron content (TEC) structures, with least root‐mean‐square errors (RMSEs). Overall, MIDAS results showed better agreement with the observation vertical TEC (VTEC) with computed maximum correlation coefficient (r) of 0.99 and minimum root‐mean‐square error (RMSE) of 2.91 TEC unit (1 TECU = 1,016 el m−2 over all the test stations and the validation days. Conversely, for the IRI‐2012 and GIM TEC estimates, the corresponding maximum computed r values were 0.93 and 0.99, respectively, while the minimum RMSEs were 13.03 TECU and 6.52 TECU, respectively, for all the test stations and the validation days.

3‐D Regional Imaging of Ionosphere Over Africa Through Assimilating Satellite and Ground‐Based Data

“…The IDA4D algorithm has been tested for nowcasting the regional ionosphere over South Korea (Jeong et al, 2022;Mengist, 2019;Mengist et al, 2018Mengist et al, , 2019 and over the US (V. V. Forsythe et al, 2021) by assimilating GPS TEC, COSMIC, and ionosonde NmF2 data. Using GPS-STEC and a tomographic inversion technique, a two-dimensional vertical total electron content image was generated over Africa (Chartier et al, 2014;Giday & Katamzi-Joseph, 2018). The IRI model has been modified over Africa with the use of vertical TEC (Habarulema & Ssessanga, 2016;Pignalberi et al, 2019).…”