Study On Sensitivity Of Physical Disturbance Parameters In High Resolution Numerical Model

It is a key problem for improving the quality of physical disturbances in highresolution convective Scale Ensemble Prediction to accurately select the physical parameters that are sensitive to prediction errors in cloud microphysical scheme and to deeply understand the physical mechanism and function of the physical parameters.In this paper,based on the high-resolution mesoscale numerical weather forecast model WRF(weather research forecast),on the basis of the prediction performance analysis of microphysical parameterization scheme,the sensitivity of microphysical parameters is selectively tested and analyzed.Firstly,the multi microphysical parameterization scheme is selected,and the best microphysical parameterization scheme,wsm5 scheme,is selected based on the performance analysis of a rainstorm process forecast in Jianghuai.Through the sensitivity test of microphysical parameters in wsm5 scheme,the effects of different microphysical parameters on the quality of rainstorm forecast,the variation of simulated hydrate content and the physical conditions of rainstorm are discussed The micro physical parameters of the physical disturbance scheme which is suitable for the high-resolution convective scale ensemble prediction are pointed out,which provides a reference for the selection of the disturbance parameters in the physical disturbance scheme of the high-resolution ensemble prediction.The main conclusions are as follows:(1)Different microphysical schemes can cause obvious vertical velocity difference,which will affect the simulation performance of precipitation process.The precipitation magnitude simulated by wsm5,wsm6 and Goddard schemes is more consistent with the actual situation.The precipitation area simulated by Lin scheme is effective,but the precipitation is less.The content of rainwater and cloud water simulated by wsm5 is higher,and the quality of precipitation and area is better.(2)Under the high-resolution forecast model,the numerical simulation quality of Jianghuai rainstorm has strong sensitivity to the rain falling speed coefficient,snow falling speed coefficient and raindrop intercept parameter in wsm5 scheme,and has significant influence on the intensity and falling area of rainstorm.(3)In the scheme of cloud microphysical parameterization,the content of hydrate is one of the most sensitive physical quantities to the quality of rainstorm forecast.Under different schemes,the simulated hydrate content is obviously different,and different physical parameters have different effects on different hydrates.For example,the rain falling velocity coefficient and the raindrop intercept parameter affect the liquid particles in the lower atmosphere,while the snow falling velocity coefficient affects the ice particles in the upper atmosphere.Due to the influence of physical parameters on the content of water products in different degrees,the water vapor conditions in the whole atmosphere will change,and at the same time,the convergence and rise of water vapor in the strong convection area will be affected.