Spatiotemporal Variation Characteristics of hE in the Tibetan Plateau and Its Surrounding Areas

Abstract The Qinghai‐Tibet Plateau, located on the “Roof of the World,” features complex terrain with the world's largest elevation gradient and is often referred to as the “Third Pole.” It serves as a natural laboratory for investigating coupling mechanisms among different atmospheric layers. Utilizing ionospheric E‐layer height (hE) data from the Qinghai‐Tibet Plateau and its surrounding regions spanning a full solar activity cycle from 2013 to 2023, this study systematically examines the diurnal, seasonal, and solar‐cycle variations of hE as well as regional differences in the area. The results reveal that hE in this region is generally controlled by solar radiation, exhibiting a gradual increase with latitude. However, two stations—Chongqing and Lanzhou—show distinct anomalies: the mean hE at Chongqing is 3–5 km higher than that of stations at similar latitudes, while the mean hE at Lanzhou is 1–3 km lower. The anomalous hE variations in the Qinghai‐Tibet Plateau and its surrounding areas may be attributed to the fact that, in addition to solar radiation control, the region's complex topographic structure influences the direction and velocity of lower‐atmosphere motions. This, in turn modulates the E‐layer height and electron density distribution through the excitation of atmospheric gravity waves and planetary waves. Within this cross‐layer atmospheric coupling process, the unique topography of the Qinghai‐Tibet Plateau plays a key role. Investigating the variation characteristics of E‐layer height over the Qinghai‐Tibet Plateau and its surrounding regions is of great significance for revealing the mechanisms of vertical atmospheric coupling and for developing multi‐sphere atmospheric coupling models.