关键词: 高原低涡, 西南低涡, 持续性暴雨, 低空急流

Abstract:

Based on NCEP 1°×1° reanalyzed data, the intensive meteorological observation stations data, sounding data and FY-2E satellite cloud images, the persistent and exceptionally severe rainstorm process which occurred in Sichuan Basin from 29 June to 2 July 2013 was analyzed. Results are as follows: (1) The plateau low vortex and Southwest China low vortex were the direct influencing systems of this heavy rainstorm, the advantageous circulation field led the two low vortexes moving eastward and being stable over Sichuan Basin.(2) The setting up and maintaining of southwest jet provided abundant water vapor and unstable energy for rainfall area, and made middle scale system maintain and develop.（3）The intense divergence on up level and common effect of the plateau low vortex and Southwest China low vortex made positive votex maintain on low level and ascending airflow form over the Sichuan Basin, which was the important condition for genesis and development of the heavy rainfall. (4) The sustaining maintaining of low votex over the basin urged mesoscale convective cloud clusters to be stable and developing, and hourly rainfall intensity at Suining station well corresponded to TBB values. (5) The large area precipitation echo passing from Lezhi to Suining formed the “train effect” and  resulted in the heavy rainfall. The mesoscale cyclone occurring on the precipitation echo band was the direct reason of the local heavy rainstorm. And this mesoscale cyclone lasted long time, which showed that connection system didn’t decrease speedily.

Key words: plateau vortex, Southwest China vortex, persistent, severe rainstorms, low level jet