The atmospheric research station was established in October 2002 at Tongyu (44.42°N, 122.87°E) located in a continental semi‐arid area of northeastern China, where it faces the Horqin desert on the west at an elevation of 184 m above sea level (Figure 1). In fact, Tongyu lies in an interlaced area of cropland (corn or sorghum) and degraded grassland, and a seesaw battlefront between semi‐arid and semi‐humid regions with a mean annual rainfall of 404 mm, which acts as a good indicator of the extent of the arid or humid area due to regional climate change.