Storm Weather Diagnostic Analysis And Numerical Simulation Of Torrential Rain In Weihe River Basin Flood

This paper studied The North of Qinling Mountains rainfall,which was the relationship between the total flood and the Weihe River flood peak flows,and to consider The North of Qinling Mountains that is the important Weihe River flood runoff area,to utilize The North of Qinling Mountains rainfall and the rainfall numerical weather prediction can be expected in the Weihe River downstream flooding,and statistical analyzed the process of flood-inducing heavy rain occurred 53 times in Weihe River basin,and summarized the rule of the flood-inducing heavy rain.According to the characteristics of induced reason,precipitation distribution and so on,the process of flood-inducing heavy rain were divided into four kinds.We analyzed a flood-inducing heavy rain using the synoptic meteorology principle and the moist-specific available energy knowledge,summarized the synoptic meteorology model of heavy rain and discussed the corresponding relations between the kinds of rainstorm and the weather.The process of flood-inducing heavy rain occurred on "05.10" in Weihe River Basin of Shanxi province were studied by means of the conventional observation data,the hydrological data and the NCEP reanalysis data(spatial resolution 1°xl°),from the two aspects:circulation situation and the physical vector fields.The results indicated that the severe storm which influenced by the reciprocity of the 500hPa low altitude slot,subtropical high and mesoscale characteristic and so on, occurred under the advantageous large scale weather conditions.Moreover,the physical vector fields of jet stream in upper and low level such as vorticity and divergency was advantageous to the maintenance stronger vertical velocity,which benefitted to this rainstorm.WRF model through the 2005 flood caused by heavy rain fall Weihe River Basin simulation results show that,with rain to heavy rain,strong rainfall center,as well as heavy rainfall,and so the time of the anastomosis with the basic fact,forecasting spent up to 36-48 hours;mode successfully simulated rainstorm and the main system in different time slots of the evolution of wind changes.The diagnosis of moist potential vorticity(MPV)shows that there are the instability area of MPV<0,and the negative focus of MPV located at the focus of heavy rainfall Above the rainfall area,when heavy rainfall happening.Moreover,MPV1<0,MPV2>0 and | MPV1≥MPV2 | are the favorable environment of heavy rainfall generating,finally,Sensitivity experiments further reveal the amplifying effect of terrain on the heavy rain.Analysis shows that the model can be used on different types of heavy rain for analysis and research,to a future objective of the Weihe River Basin flood forecasting Shaanxi rainstorm forecasting an important technical means and tools.