A foundation diagnostic framework reveals more frequent yet spatially shrinking local atmospheric circulations over plateau-basin regions

Abstract. Local atmospheric circulations critically affect hazardous weather and environment forecasting, yet their vertical structures remain unclear. Here, a foundational physical-constrained framework for objectively identifying and quantifying the vertical structures of terrain-driven circulations is developed and applied over the Tibetan Plateau (TP)-Sichuan Basin. Three typical circulation patterns, i.e., one-cell, two-cell, and three-cell circulations are detected for the first time, enabling quantification of their intensity, spatial extent, and central height. Results indicate that free-atmosphere circulations present higher altitudes and weaker intensity than boundary-layer circulations. For two- and three-cell patterns, west circulations adjacent to the TP expand and weaken during daytime but contract and descend at nighttime. From 1980 to 2022, local atmospheric circulations become more frequent while spatial extent shrink, suggesting enhanced localization of frequent convective weather and air pollution. These findings provide a basis for vertical quantification of terrain-driven circulations, supporting operational forecasting of hazardous weather and environment over plateau-basin regions.