Numerical Simulation Of Deep Convection System On Pollutant Gas Transportation

In this paper,Weather Research and Forecasting model coupled with chemistry(WRF-Chem)is used to simulate the vertical transport of pollutant gases in deep convective systems.The effects of different convective systems on the transport effect are studied.Different physical and planetary boundary layer parameterizations are used to simulated different convective systems to study the effects of different parameterization schemes on the vertical transport of pollutants in deep convection.The Weather Research and Forecasting(WRF)model with chemistry has been used to investigate the redistribution of pollutant gases CO in the two deep convections convective systems occurred over the Yangtze River Delta on July 27 and August 24,2014.The onset of the convection and echo intensity simulated by WRF-chem were consistent with the observations when comparing with the radar observed echo properties of the convection.Both the convective available potential energy and vertical wind shear between altitudes of 0 and 6 km are larger in case July 27 than that in case August 24,which lead to more unstable and higher altitude of convective system.The analysis of vertical section of CO concentration and vertical mass fluxes showed that the deep convection of case July 27 can transport CO up to the altitude of 14 km,whereas that of case August 24 can make it up to 16 km.The difference between mean profile of CO concentration and vertical flux divergence suggested that most of the CO were transported to the altitude of ~12 km,which resulted in a higher CO concentration at the middle troposphere for case July 27;while CO were mainly transported to the altitude of ~15 km,which led to the higher CO concentration at the upper troposphere for case August 24.Analysis of vertical flux shows that deep convective transport per hour in the 24 August is 1.3 times greater than that in 27 July.As the deep convection lasts longer in 24 August,the deep convection in 24 August can transport much more CO than that in 27 July.The selection of physical and planetary boundary layer parameterizations has a great influence on the deep convection intensity and structure of the simulation.Different physical parameterizations have a great influence on the echo top height of deep convective system,and the influence on the cloud top height of the deep convective system is relatively small.Different planetary boundary layer parameterizations have relatively little influence on the echo top height of deep convective system,and have no effect on the cloud top height of the deep convective system.The selection of physical and planetary boundary layer parameterizations will also have a great influence on the effect of vertical transport of air in deep convective systems.The choice of physical parameterizations will affect the air mass flux of vertical transport.The choice of planetary boundary layer parameterizations mainly affects the time when the vertical mass flux high value appears.The analysis of the distribution of gases with different solubility in precipitation and non-precipitation regions shows that the concentration of pollutants in the precipitation and non-precipitation regions varies greatly with height.Different parameterization schemes have less influence on insoluble gases and have a greater influence on soluble gases.