Mesoscale Numerical Simulation Study of Blizzard Process in Ningxia

A numerical simulation was made on the blizzard process within Ningxia in April 11, 2012 using mesoscale numerical model WRF and global grid point data. The simulation result showed that the WRF model could simulated the distribution of the heavy snowfall better. The result of the diagnostic analysis further showed that the formation of the 700 hPa southwest jet and 850 hPa northeast jet provided an adequate moisture conditions for the occurrence of the heavy snowfall.During the heavy snowfall process, due to a strong low level convergence that leading to a stronger ascending motion, the amount of water vapor convergence below 500 hPa increased significantly, the low layer was filled with moisture, the negative zone of the vertical velocity maintained and strengthened, the water vapor condensation in the vertical direction causing by these was the mechanism of the formation of the heavy snowfall. It provided a favorable condition for the occurrence of the blizzard.