Large-Scale Ionospheric Irregularities Detected by Ionosonde and GNSS Receiver Network

Large-scale ionospheric irregularities, which occurred on September 8, 2017, were detected by the ionosonde and the Global Navigation Satellite System (GNSS) receiver network in this letter. The Wuhan ionospheric sounding system (WISS), deployed at Puer (PUR, 22.7 degrees N, 101.05 degrees E), Leshan (LSH, 29.6 degrees N, 103.7 degrees E), and Zhangye (ZHY, 39.4 degrees N, 100.13 degrees E), detected these large-scale ionospheric irregularities. The 2-D maps of the rate of the GNSS total electron content (TEC) index (ROTI) further confirmed that the large-scale ionospheric irregularities can cover a broad area (from the equator to middle latitude, similar to 80 degrees E to similar to 120 degrees E, similar to 20 degrees N to similar to 45 degrees N). The ionospheric variation recorded by the WISS shows that the large-scale ionospheric irregularities were driven by the super eastward electric field, which was formed by the eastward prompt penetration electric field during a storm superimposed on the normal prereversal enhancement during the postsunset hours. Moreover, observations by the WISS show the higher the latitudes at which the ionospheric irregularities/spread F occurred, the shorter the duration time.