Scenario Projections for the Ascent–Drift–Descent Radiosonde System Observations

To assess the application potential of the ascent–drift–descent radiosonde system (ADDRS) data over China, and to provide reference for the receiving station deployment, scenario projections for nationwide ADDRS network observations are conducted by using trajectory simulation data from the ADDRS trajectory prediction system. Based on the Beidou Sounding System of China, this study investigates the spatial distribution of descent-phase landing points of the ADDRS. The distances, azimuths, and seasonal variations of landing points relative to sounding stations are analyzed, together with the frequency of cross-border landings near border regions. In addition, the frequency distribution characteristics of landing points are examined, and a priority index for the deployment of additional receiving stations is proposed in conjunction with existing receiving station coverage. The results show that ADDRS landing points can nearly cover all land areas of China. In winter, the drifting distance of landing points relative to the sounding stations increases with latitude, reaching up to 1400 km, with landing points at high-latitude stations being more dispersed. During summer, the drifting distance decreases with latitude, and the landing points for low-latitude stations are more concentrated. The azimuth of landing points follows the prevailing wind direction in the stratosphere, exhibiting an east–west orientation, with distinct seasonal variations. The priority index for receiving station deployment suggests that approximately 443 receiving stations are needed to cover the entire region of China, enabling simultaneous ADDRS operations at all sounding stations nationwide.