Abstract:
Based on NCEP (1°×1°) FNL data and various dense observation data, two local heavy rainstorm processes that occurred in summer 2017 (June 29) and autumn 2018 (September 7) were compared and analyzed, intended to provide a reference for the forecast and warning of local heavy rainstorms in different seasons in Kunming in the future. The conclusions are drawn as follows: ① The rain belt of the “06.29” rainstorm process demonstrated a NW—SE direction, while the “09.07” process showed a quasi-north-south direction. The “06.29” rainstorm process was significantly greater than the “09.07” process in terms of intensity, duration and quantity of precipitation, as well as heavy precipitation range. ② The main impact system of the “06.29” process was the low trough shear line, and the water vapor mainly came from the Bay of Bengal, while the main impact system of the “09.07” process was the tropical low pressure in the eastern South China Sea and the near-surface cold front, and the water vapor mainly came from the South China Sea. The system of the “06.29” process was significantly deeper and thicker than that of the “09.07” process and moved slower. ③ The convective environments of the two processes were conducive to the occurrence of short-term heavy precipitation and strong convective weather. The convective environmental conditions of the “06.29” process were obviously stronger than those of the “09.07” process. ④ The average radial velocity of the station with the largest hourly rainfall showed that volume scannings of all the 10 stations simultaneously exhibited velocity convergence and reverse wind region in the “06.29” process, and that volume scannings of 8 stations simultaneously exhibited velocity convergence and reverse wind region in the “09.07” process. ⑤ The radar echo of the “06.29” process evolved into a sheet-like mixed echo and remained for a long time in the northern part of Kunming, the echo moved very slowly, and the backward propagation characteristics were obvious. The radar echo of the “09.07” process evolved into a continuous convective single storm near the cold front, showing a NW—SE direction, forming a mixed echo with a band-like distribution in the NW-SE direction and moving southwestwards. The echo moved fast and the train effect was obvious.