资源环境科技发展态势分析平台

The E‐region equatorial electric field (EEF) modulates distributions in the ionosphere at equatorial and low latitudes via the fountain effect. Using Swarm data during the daytime and geomagnetically quiet periods (Kp ≤ 3), we perform a detailed analysis of the main wave sources of the longitudinal structures of the EEF (LS_EEF) in different seasons by fitting the LS_EEF with longitudinal wavenumber 1–4 patterns (WN1–WN4), and further matching the dominant tides and stationary planetary waves. The results indicate that: (1) Although the LS_EEF exhibit significant seasonal dependence, a prominent one‐peaked structure exists in all seasons (peak: 90°E–120°E; trough: 30°W–70°W). (2) WN1 (WN4) contributes most to the LS_EEF over four seasons (spring to autumn) with fractions of 26%–39% (25%–38%). (3) The main wave sources of the LS_EEF are DW2 (DE3 and DE2; DE3; DW2 and SW4) in spring (summer; autumn; winter) with each contribution exceeding 15%.