Kinetic Energy Spectrum Analysis And Predictability Of Mei-yu Rainstorm

Using WRF mode and high-resolution reanalysis data,the three-stage torrential rain in the continuous precipitation process during the Mei-yu period in 2016 was diagnosed and analyzed.The kinetic energy spectrum characteristics and kinetic energy budget of the actual Mei-yu rainstorm were analyzed by simulation results.By designing the disturbance test,the relationship between initial disturbance growth and precipitation is analyzed,and the error kinetic energy budget spectrum equation is derived and diagnosed.The main conclusions are as follows:(1)The three-stage torrential rain process during continuous rainfall in the Mei-yu period differs in terms of circulation,water vapor source,heat,dynamic conditions and frontal effects.The first torrential rain is a typical Mei-yu rainstorm circulation feature.The abundant water vapor,thermal instability and strong ascending motion,and obvious high and low air jets have the strongest precipitation.(2)The kinetic energy spectrum analysis of the rainstorm process found that in the actual Mei-yu rainstorm,the WRF model can also replicate the mesoscale kinetic energy spectrum characteristics.The mesoscale kinetic energy increases during the rainstorm development stage,and the spectral transition scales of different height layers are different.The increase of kinetic energy starts significantly at the lower end of the mesoscale.The tropospheric vortex kinetic energy is greater than the divergent kinetic energy,and the stratosphere lower layer is opposite.The different precipitation stages and different height kinetic energy sources are different.(3)The analysis of error kinetic energy spectrum shows that the distribution and evolution of the error level kinetic energy spectrum have similar characteristics to the kinetic energy spectrum,but during the rainstorm development period,the error kinetic energy of the larger mesoscale increases more significantly;the tropospheric upper-scale error kinetic energy increases.Mainly due to nonlinear effects,while the lower stratosphere is mainly derived from the barometric pressure term.