A Numerical Simulation On The Influence Of An Overshooting Convection On The Humidity In UT/LS

A deep convection process in Lingbi area of Anhui has been simulated by using Weather Research and Forecasting (WRF) mesoscale model coupled with the Morrison’s double-parameters microphysical solution and other three microphysical scheme, the vertical transport of water vapor by deep convection and the influence on humidity of UT/LS (Upper Troposphere and Lower Stratosphere) area has been analyzed in this study. These results are very helpful for us to understand the influence of deep convective vertical transport process on the UT/LS regional atmosphere environment. The results are showing as follows:(1) The simulated characteristics of the storm by WRF model revealed a good agreement to observations in the following aspects, such as the location of convection, the location of precipitation and the height of cloud.(2) The flux density of water vapor transported by deep convection presented a tendency which increased firstly and then decreased, the flux density of water was very sensitivity under15km, however, the tendency was not sensitivity to the different microphysics parameter solutions. The simulation schemes were the fundamental cause of the simulation difference on vertical speed.(3) The results of Morrison scheme were prominent in the aspect of LS moistening which affected by deep convection, the averaged mixing ratio of water vapor in different height at UT/LS area was about hundred times higher in the moistening phases than before, and the moistening period continued more than8hours. The moistening area at least10%higher than before covered at least2.1latitudes and3.3longitudes at18.054km altitude. The results showed that the water vapor transported by deep convection was the primary reason of moistening at the LS and the sublimation of hydrometeor moistened this area weakly. The stratosphere water vapor content is sensitive to cloud microphysical schemes. Specifically, the duration time of overshooting was about4.5to8hours in different schemes and the averaged water vapor mixing ratio was about7times difference among different schemes. The moistening area was at least10%higher than before at18.054km altitude which was sensitive to cloud microphysical parameterization schemes. The maximum was about1.5latitudes and longitudes lager than the minimum.