Abstract:
Use NCEP 6-hour reanalysis data (1°×1°)and conventional observation data to analyse the water vapor condition of a rainstorm process in northerast Sichuan in May 2~3, 2017.The results show that:(1) Before the rainstorm started, the water vapor content soared, the thickness of wet layer increased, and maintained in the whole process of high humidity; The water vapor in the rainstorm increased gradually with the time from south to North.(2) The total amount of water vapor in the storm area is positive for the whole period, and the large value of water vapor revenue coincides with the beginning time of the two precipitation periods, the meridional water vapor input plays a major role in this process.(3) The main sources of water vapor are the Bay of Bengal and the South China Sea and the water vapor transport is dominated by 850~700hPa, gradually decreasing from south to north, the southern humid layer is thicker and corresponds to the heavy rainfall area.(4) In the first stage of precipitation, water vapor convergence of low-level and divergence of high-level, the convergence between the two stages of precipitation is weakened and then enhanced and continues until the end of the process.