To represent well the characteristics of temporal and spatial distributions, chart of 3-dekad moving total precipitation is proposed in this paper first. Then this kind of chart is expanded in terms of Chebyshev polyn...To represent well the characteristics of temporal and spatial distributions, chart of 3-dekad moving total precipitation is proposed in this paper first. Then this kind of chart is expanded in terms of Chebyshev polynomial at irregular grids, and the quantitative representation of precipitation is got. Finally the Chebyshev coefficients are forecasted by using the forecasting method of vector similarity in phase space proposed by Zhou (1992). Using above mentioned procedures temporal and spatial distributions of precipitation over the Huanghe-- Huaihe-- H aihe Plain in China are forecasted.展开更多
In this paper,the effects of surface roughness on tornado-like vortices are studied in the laboratory for simulating tornado vortex at the Disaster Prevention Research Institute,Kyoto University,Japan. In the experime...In this paper,the effects of surface roughness on tornado-like vortices are studied in the laboratory for simulating tornado vortex at the Disaster Prevention Research Institute,Kyoto University,Japan. In the experiments,the distribution of the horizontal wind speed and direction at five different heights were measured with a hot-wire anemometer and a mini-vane.The characteristics of wind speed and direc- tion distribution for the tornado vortex on the various rough surfaces were first revealed with the simulative method in laboratory.By changing the swirl ratio(S=tanθ/2a)of simulation device,it is found that,the size of tornado-like vortex core will become almost identical,as the swirl ratio S exceeds a certain value (S>1.5). The experimental results can be used not only to explain the observed facts in the atmosphere but also to provide the experimental bases for some theoretical studies.展开更多
文摘To represent well the characteristics of temporal and spatial distributions, chart of 3-dekad moving total precipitation is proposed in this paper first. Then this kind of chart is expanded in terms of Chebyshev polynomial at irregular grids, and the quantitative representation of precipitation is got. Finally the Chebyshev coefficients are forecasted by using the forecasting method of vector similarity in phase space proposed by Zhou (1992). Using above mentioned procedures temporal and spatial distributions of precipitation over the Huanghe-- Huaihe-- H aihe Plain in China are forecasted.
文摘In this paper,the effects of surface roughness on tornado-like vortices are studied in the laboratory for simulating tornado vortex at the Disaster Prevention Research Institute,Kyoto University,Japan. In the experiments,the distribution of the horizontal wind speed and direction at five different heights were measured with a hot-wire anemometer and a mini-vane.The characteristics of wind speed and direc- tion distribution for the tornado vortex on the various rough surfaces were first revealed with the simulative method in laboratory.By changing the swirl ratio(S=tanθ/2a)of simulation device,it is found that,the size of tornado-like vortex core will become almost identical,as the swirl ratio S exceeds a certain value (S>1.5). The experimental results can be used not only to explain the observed facts in the atmosphere but also to provide the experimental bases for some theoretical studies.
