A precipitation system developed continuously along the western coastline of the Korean Peninsula and created considerable precipitation both along the coast and inland on 26 July 2011. In this study, the causes for t...A precipitation system developed continuously along the western coastline of the Korean Peninsula and created considerable precipitation both along the coast and inland on 26 July 2011. In this study, the causes for this nearshore convective system are investigated from observations and the results of model experiments. Three-dimensional radar fields clearly show that a change of wind at the surface border played an important role in the development of the nearshore convection system. The simulation results, which are very similar to the observations, show that the surface border generated and maintained the convergence zone. The roughness change enhanced the convergence, and the interaction between the deepening cold pool and downward flow maintained the convergence zone. The surface mechanical discontinuity affected by the roughness change between sea and land formed the convergence (gradient of wind stress), which induced momentum transfer to the upper layer. The cold pool created a steep gradient of potential temperature and provided the reason for the propagated convergence zone with the downward flow. The maximum value of the surface change factor, which comprises the influencing factors for the long-lasting convective system, reflects the enhancement of the system at the coast.展开更多
The Global Alliance of Disaster Research Institutes held its 3rd Global Summit of Research Institutes for Disaster Risk Reduction at the Disaster Prevention Research Institute,Kyoto University,Japan,19–21 March,2017....The Global Alliance of Disaster Research Institutes held its 3rd Global Summit of Research Institutes for Disaster Risk Reduction at the Disaster Prevention Research Institute,Kyoto University,Japan,19–21 March,2017.The Global Alliance seeks to contribute to enhancing disaster risk reduction(DRR) and disaster resilience through the collaboration of research organizations around the world.The summit aim was to expand the platform for bridging science and policy making by evaluating the evidence base needed to meet the expected outcomes and actions of the Sendai Framework for Disaster RiskReduction 2015–2030 and its Science and Technology Roadmap.The summit reflected the international nature of collaborative research and action.A pre-conference questionnaire filled out by Global Alliance members identified323 research projects that are indicative of current research.These were categorized to support seven parallel discussion sessions related to the Sendai Framework priorities for action.Four discussion sessions focused on research that aims to deepen the understanding of disaster risks.Three cross-cutting sessions focused on research that is aimed at the priorities for action on governance,resilience,and recovery.Discussion summaries were presentedin plenary sessions in support of outcomes for widely enhancing the science and policy of DRR.展开更多
The removal of snow from a road or railroad results in an uneven surface and thus the formation of snowdrifts. However, the effect of a surface bump on the scale of a snowdrift is not clear. Snowdrift wind tunnel test...The removal of snow from a road or railroad results in an uneven surface and thus the formation of snowdrifts. However, the effect of a surface bump on the scale of a snowdrift is not clear. Snowdrift wind tunnel tests have long been performed to predict the snow cover distribution due to a snowstorm. However, such tests require a large-scale experimental device, have high installation and maintenance costs, and are not easy to perform. The present study thus used a small water tunnel that is easier to implement. The snowdrift pattern for the real phenomenon of a cube model was reproduced using the small water tunnel and the performance of the tunnel thus verified. The snowdrift water tunnel was then used to predict the snowdrift distribution for uneven surfaces. The tunnel well reproduced the snow cover distribution when the sedimentation velocity ratio and Stokes number in the water tunnel test were the same as those for the real phenomenon, again verifying the performance of the water tunnel test.展开更多
基金funded by the Korea Meteorological Institute (Grant No. KMI 2018-05410)
文摘A precipitation system developed continuously along the western coastline of the Korean Peninsula and created considerable precipitation both along the coast and inland on 26 July 2011. In this study, the causes for this nearshore convective system are investigated from observations and the results of model experiments. Three-dimensional radar fields clearly show that a change of wind at the surface border played an important role in the development of the nearshore convection system. The simulation results, which are very similar to the observations, show that the surface border generated and maintained the convergence zone. The roughness change enhanced the convergence, and the interaction between the deepening cold pool and downward flow maintained the convergence zone. The surface mechanical discontinuity affected by the roughness change between sea and land formed the convergence (gradient of wind stress), which induced momentum transfer to the upper layer. The cold pool created a steep gradient of potential temperature and provided the reason for the propagated convergence zone with the downward flow. The maximum value of the surface change factor, which comprises the influencing factors for the long-lasting convective system, reflects the enhancement of the system at the coast.
文摘The Global Alliance of Disaster Research Institutes held its 3rd Global Summit of Research Institutes for Disaster Risk Reduction at the Disaster Prevention Research Institute,Kyoto University,Japan,19–21 March,2017.The Global Alliance seeks to contribute to enhancing disaster risk reduction(DRR) and disaster resilience through the collaboration of research organizations around the world.The summit aim was to expand the platform for bridging science and policy making by evaluating the evidence base needed to meet the expected outcomes and actions of the Sendai Framework for Disaster RiskReduction 2015–2030 and its Science and Technology Roadmap.The summit reflected the international nature of collaborative research and action.A pre-conference questionnaire filled out by Global Alliance members identified323 research projects that are indicative of current research.These were categorized to support seven parallel discussion sessions related to the Sendai Framework priorities for action.Four discussion sessions focused on research that aims to deepen the understanding of disaster risks.Three cross-cutting sessions focused on research that is aimed at the priorities for action on governance,resilience,and recovery.Discussion summaries were presentedin plenary sessions in support of outcomes for widely enhancing the science and policy of DRR.
文摘The removal of snow from a road or railroad results in an uneven surface and thus the formation of snowdrifts. However, the effect of a surface bump on the scale of a snowdrift is not clear. Snowdrift wind tunnel tests have long been performed to predict the snow cover distribution due to a snowstorm. However, such tests require a large-scale experimental device, have high installation and maintenance costs, and are not easy to perform. The present study thus used a small water tunnel that is easier to implement. The snowdrift pattern for the real phenomenon of a cube model was reproduced using the small water tunnel and the performance of the tunnel thus verified. The snowdrift water tunnel was then used to predict the snowdrift distribution for uneven surfaces. The tunnel well reproduced the snow cover distribution when the sedimentation velocity ratio and Stokes number in the water tunnel test were the same as those for the real phenomenon, again verifying the performance of the water tunnel test.
