1986年6月26—27日京津冀大暴雨的数值试验研究

NUMERICAL SIMULATION OF THE 26—27 JUNE 1986 HEAVY RAINFALL IN BEIJING-TIANJIN-HEBEI AREA

用移植到 DPS-7机上的美国 PSU/NCAR 中尺度模式 MM4对1986年6月26—27日京津冀地区大暴雨过程进行了数值试验。结果表明:高空对流区附近风速减小和低空急流核加强并通过暴雨区对暴雨起决定性的影响;潜热的反馈作用、下垫面提供的热量和水汽通量对降水有重要影响。大陆以东洋面的水汽供应以及西北涡在这次暴雨过程中的作用不显著。另外,采用显式降水方案后,预报的降水落区、中心位置和量值均有所改进。

By use of the transplanted mesoscale model(MM4)from PSU/NCAR,a strong rainfall eventduring 26—27 June 1986 in Beijin-Tianjin-Hebei area is simulated.The results show that the re-duction in wind speed near the convective region in upper levels and passage through the rainfallcenter of the intensifying LLJ played crucial role in the event.The mergence of meso-low withconvergence region ahead of the LLJ,feedback of latent heat release,and fluxes of heat and mois-ture from the underlying surface were also responsible for the event whereas the northwest lowdid not contribute much to precipitation.