A numerical simulation on the relation between water vapor content variation in upper troposphere and strong convection weather in high latitude areas

Weather Research Forecast(WRF) model is used for studies of dynamic causes and thermal mechanisms of the rainstorm in the southwest of Heilongjiang. The vertical transport of water vapor by a severe convective process has been investigated using the WRF model with different cloud micro-physical schemes. The major conclusions are as follows:severe convections make local vapor in upper troposphere increase over 10 times,which shows that severe convections have a significant effect on both the vapor vertical transportation and the vapor content change in the upper troposphere. When the convective cloud arises,the trend of the water vapor flux density over the whole troposphere is not sensitive to cloud microphysical schemes. The strength of water vapor flux and the total water vapor flux integrated over a period of 24 h are sensitive to cloud microphysical schemes,which is correlated to the vertical updraft in the cloud. The largest difference in the maximum total water vapor can reach 27. 9% among different schemes. Both the humidifying effect in the upper troposphere and the duration are sensitive to cloud microphysical schemes. The cumulus transport leads to humidification of the upper troposphere,which lasts from 16 to 20 h. The maximum differences in the upper troposphere water vapor mixing ratio can reach15. 8%. The averaging of 24 h may reduce the sensitivity of upper troposphere humidity,but the maximum still can reach 8. 3%. The uncertainty induced by different microphysical schemes cannot be neglected within time scale of the rainstorm.