Abstract:Based on conventional observation data and Suizhou S-band dual-polarization weather radar observation data, the short-time heavy rainfall events are classified into strong synoptic-scale system forcing type (strong forcing type) and weak synoptic-scale system forcing type (weak forcing type) according to the weather circulation patterns. The distribution characteristics and dual-polarization radar echo characteristics of the two are comparatively analyzed. The results show that the strong forcing type of short-time heavy rainfall occurs more frequently at more stations, covering wider areas and lasting longer. July has the highest frequency of this type of heavy rainfall, followed by June and then August. Dahong Mountain and Tongbai Mountain are the areas where the strong forcing type of heavy rainfall most frequently. The daily variation characteristics of such rainfall show a three-peak pattern, with the highest occurrence from 05:00 BT to 08:00 BT, then from 22:00 BT to 01:00 BT the next day, and at around 15:00 BT in order. In terms of the weak forcing type of short-time heavy rainfall, its occurrence frequency is basically the same in July and August, with the least in June. The distribution of its high-frequency areas is scattered, but mountainous areas are still the high-frequency areas. Its daily variation follows a unimodal distribution, with the peak occurring at 15:00 BT. Both types of short-time heavy rainfall have the characteristics of higher rainfall intensity, the corresponding stronger echo intensity, higher concentration of liquid particles, higher echo top, and larger diameters of liquid particles. At the same rainfall intensity level, the two types of heavy rainfall do not show significant differences in composite reflectivity, horizontal reflectivity at 1 km height, and echo top height, and they all have low centroid characteristics, with the strong forcing type having more obvious low centroid characteristics. However, the interval and average values of the 1 km differential reflectivity and specific differential phase for the strong forcing type are significantly smaller than those for the weak forcing type, while the interval and average values of the 1 km correlation coefficient are slightly larger than those for the weak forcing type.