Numerical Simulation Study on Two Rainstorms in Guizhou Province in June,2011

By using the theory of moist potential vorticity(MPV),the characteristics of θ_se and MPV are analyzed in the process of two typical rainstorms(from 08:00am on 17 June 2011 to 20:00pm on 18 June 2011(process Ⅰ) and from 08: 00 am on 22 June 2011 to 20:00pm on 23 June(process Ⅱ) based on precipitation data of 84 meteorological stations and 1473 automatic stations,the ECMWF reanalysis data with 0. 25°×0. 25° spatial resolution and the numerical simulation results of WRF model. The results show that the“Process I”is affected by the cold air,the“process II”is affected by two cold air. The center of the convergence and divergence in the “process Ⅰ”rainstorm process respectively are at 800hPa and 500hPa along 27° N,107° E. The convergence center in the“process Ⅱ”rainstorm process is at 800hPa along 27°N,107°E and the divergence center is at 750hPa along 28°N,107°E. The positive value centers of MPV1 and the negative value centers of MPV2 from as high as 700hPa are almost consistent with the heavy rainfall area(from Xingren to Qinglong to Anshun and from Jinsha to Meitan to Wuchuan) in the “process Ⅰ”rainstorm process,and The two positive value centers of MPV1 and the negative value centers of MPV2 from as high as 700hPa are almost consistent with the heavy rainfall area(Bijie and Liuzhi) in the“process Ⅱ”rainstorm process. The MPV1 value of the two rainstorm weather process is obviously larger than that of MPV2. WRF model to simulate the water vapor convergence center intensity than live on the strong side,simulation of“process I ”convergence zone than live too small,simulation of“process II ”convergence zone than the live is too large. WRF model simulation“process I”of the MPV1 positive area center value is smaller than the live,analog“process II”MPV1 positive area center value is larger than the live,but the positive value of the center and the center of the strong precipitation center. WRF model for the two rainstorm process MPV2 negative center of the simulation are shown to be less accurate. The cold air ratio of WRF model is stronger than that of live,and the center of heavy rain is larger than the actual value. The“process I”simulation of the heavy rain center location than the live south 10 km,“process II”simulation of the heavy rain center location than the live south 7km. Reference for the β-scale heavy rain in Guizhou.