Analysis and Prediction of Local Heavy Rainfall in Mountainous and Urban Area

点击翻译按钮获取中文摘要

In this project, investigators have proposed the severe rainfall prediction system as well as they have analyzed the local heavy rainfall. The analysis of local heavy rainfall has been done by twoapproaches. First, investigators observed several severe reinfall events mainly with radio sonde and rain gage under condition of severe rainfall in Baiu. Second, investigators developed a cumulus cloud model which has terrain following coordinate and detailed microphysics model. Using the model, investigators simulate severe rainfall events. The processes and result of the analysis is as follows ;1) Hydrological and meteorological observations have been done under condition of severe rainfall which came mainly from Baiu fronts at the Kuzuryu river basin in Fukui Prefecture. Observation period is June 20-30,1996 and July 2-10,1997. Observations have been done with radio sonds (two to three hourly), optical and normal rain gage (once par one to ten minutes), car bone X band radar (continuous).2 … More ) Numerical cumulus model which has detailed cloud microphysics have been computed with observation data as initial and verification data. Investigators analyze the effect of topography, wind field, atmospheric and thermodynamic stability and water vapor on cloud microphysical processes which control the cumulus generation and dissipation. As results of the analysis, investigators obtained results that the amount of hail generation is important factor for rainfall amount from cumulus. Moreover, they found that water vapor and vertical wind are important factor for hail generation.3) Investigators proposed that GPS is suitable observation system for water vapor observation. Moreover, they developed a new equation system in order to obtain the water vapor disturbance of cumulus scale using GPS.Investigators found that the equation system made good results using numerical simulation data. They also investigated efficiency of the equation system using observed GPS data. Investigation found that the equation system is effective under good observation condition. They also found that the observation data are affected by many kind of error sources.Finally, the vertical wind field observation by Doppler radar and water vapor observation by GPS are proposed as a effective observation system for severe rainfall prediction. Less