Morphological Characteristics of Thousand‐Kilometer‐Scale E<sub>s</sub> Structures Over China
Wenjie Sun, Xiukuan Zhao, Lianhuan Hu, Sipeng Yang, Haiyong Xie, Shoumin Chang, Baiqi Ning, Jianyong Li, Libo Liu, Guozhu Li
Abstract
Abstract Sporadic E (E s ) structures have been observed occasionally covering a large horizontal scale of more than 1,000 km over China. Their onset locations and propagation features, and related generation mechanisms still remain unknown. In this study, a statistical analysis of large‐scale E s structures is performed based on the ionospheric total electron content obtained from ground‐based receiver networks, in combination with data from multiple ionosondes in China. The large‐scale strong E s structures mainly occur during summer months, with dominant horizontal azimuth in the east‐west and northwest‐southeast directions and dimensions of 1,000–3,000 km along the elongation. They predominantly drift southwestward at the speed of 30–210 m/s. The main onset region for the large‐scale E s structures over China is identified for the first time, which is around 20°–45°N and 100°–125°E. Based on the morphological features of large‐scale E s structures, and the observation of concurrent cases of traveling ionospheric disturbances, we surmise that gravity waves could play an important role in the generation of large‐scale E s structures.