The Cangshan Mountain Precipitation Experiment (CAMPEX): Modulation of Precipitation by Typical Steep Mesoscale Terrain over Southwest China

To address the scarcity of observational data constraining in-depth research on topographic precipitation, the Cangshan Mountain Precipitation Experiment (CAMPEX) was launched by the Chinese Academy of Meteorological Sciences and Yunnan Provincial Meteorological Bureau. Focused on the quasi-north–south-oriented Dali Cangshan Mountain, a region with a pronounced precipitation enhancement effect in Southwest China, CAMPEX aims to elucidate how steep meso-γ-scale terrain modulates large-scale systematic precipitation and locally triggered convection. For this purpose, three core observation zones across the mountain peak and the eastern and western valleys are equipped with X-band and Ka-band radars, microwave radiometers, disdrometers, Doppler wind lidars, and other advanced instruments. The 5-yr experiment has completed 2 intensive observing periods to date (20 June–31 October 2024 and 1 May–31 October 2025), capturing 17 systematic precipitation events and 14 locally triggered convective processes under dominant weather conditions such as shear lines, typhoon remnants, frontal systems, southern branch troughs, and weak synoptic-forcing scenarios. Advances in cross-instrument quality control, multi-radar mosaics, and three-dimensional (3D) wind-field retrieval over complex terrain, have enabled comprehensive monitoring of precipitation evolution, filling previous radar blind zones. The campaign has produced high-resolution datasets including 3D winds, thermodynamic profiles, and cloud microphysics. Another distinct feature of CAMPEX is a hectometer-resolution numerical forecasting system designed particularly for the Cangshan region, operating synchronously with the field campaign. Preliminary analysis confirms the reliability of the acquired data and has provided potential insights into how the Cangshan terrain enhances precipitation of different types. This paper outlines the design and implementation of CAMPEX, and presents the dataset and early scientific findings obtained thus far.