Realistic modeling and rendering of dynamic tornado scene is recognized as a challenging task for researchers of computer graphics. In this paper a new physically based method for simulating and animating tornado scen...Realistic modeling and rendering of dynamic tornado scene is recognized as a challenging task for researchers of computer graphics. In this paper a new physically based method for simulating and animating tornado scene is presented. We first propose a Two-Fluid model based on the physical theory of tornado, then we simulate the flow of tornado and its interaction with surrounding objects such as debris, etc. Taking the scattering and absorption of light by the participating media into account, the illumination effects of the tornado scene can be generated realistically. With the support of graphics hardware, various kinds of dynamic tornado scenes can be rendered at interactive rates.展开更多
Though drought is a recurrent phenomenon in the Jinghe watershed, very little attention has been paid to drought mitigation and preparedness. This article presents a method for the spatial assessment of agricultural d...Though drought is a recurrent phenomenon in the Jinghe watershed, very little attention has been paid to drought mitigation and preparedness. This article presents a method for the spatial assessment of agricultural drought risk in the Jinghe watershed of western China at a 1-km grid scale. A conceptual framework, which emphasizes the combined roles of hazard and vulnerability in defining risk, is used. The Z index method in a GIS environment is used to map the spatial extent of drought hazards. The key social and physical factors that define agricultural drought in the context of the Jinghe watershed are indentified and corresponding thematic maps are prepared. Risk is calculated by the integration of hazard and vulnerability. Results show that the risk gradient follows a north-south and west-east tendency and that agricultural droughts pose the highest risk to northern and northwestern sections of the Jinghe watershed.展开更多
基金Project supported by the National Basic Research Program (973) of China (No. 2002CB312101) and the National Natural Science Foundation of China (No. 60475013)
文摘Realistic modeling and rendering of dynamic tornado scene is recognized as a challenging task for researchers of computer graphics. In this paper a new physically based method for simulating and animating tornado scene is presented. We first propose a Two-Fluid model based on the physical theory of tornado, then we simulate the flow of tornado and its interaction with surrounding objects such as debris, etc. Taking the scattering and absorption of light by the participating media into account, the illumination effects of the tornado scene can be generated realistically. With the support of graphics hardware, various kinds of dynamic tornado scenes can be rendered at interactive rates.
基金National Key Technology R&D Program (No. 2008BAK50B05)National Key Project for basic research (973) (No.2009CB421106)the Knowledge Innovation Program of CAS (No. KZCX2-EW-306)
文摘Though drought is a recurrent phenomenon in the Jinghe watershed, very little attention has been paid to drought mitigation and preparedness. This article presents a method for the spatial assessment of agricultural drought risk in the Jinghe watershed of western China at a 1-km grid scale. A conceptual framework, which emphasizes the combined roles of hazard and vulnerability in defining risk, is used. The Z index method in a GIS environment is used to map the spatial extent of drought hazards. The key social and physical factors that define agricultural drought in the context of the Jinghe watershed are indentified and corresponding thematic maps are prepared. Risk is calculated by the integration of hazard and vulnerability. Results show that the risk gradient follows a north-south and west-east tendency and that agricultural droughts pose the highest risk to northern and northwestern sections of the Jinghe watershed.
