目前,地理信息系统(geographic information system,GIS)业界在符号库结构上还没有制定明确的、统一的标准,各GIS商业软件的符号库构建思路和结构各异.充分利用可扩展标记语言(extensible markup language,简称XML)强大的自我描述能力...目前,地理信息系统(geographic information system,GIS)业界在符号库结构上还没有制定明确的、统一的标准,各GIS商业软件的符号库构建思路和结构各异.充分利用可扩展标记语言(extensible markup language,简称XML)强大的自我描述能力、开放性、平台无关性和灵活性特点,建立一种通用的地图符号描述模型.提出异构GIS平台下地图符号共享的解决方案和实现的关键技术,并在中国岩石圈三维结构数据库项目研究中验证了通用地图符号库实用性.展开更多
The East China Sea(ECS) has a high suspended-sediment concentration because of the influence of the Changjiang River,indicated by high turbidity in the water.Considering the islands off the coast and the complex topog...The East China Sea(ECS) has a high suspended-sediment concentration because of the influence of the Changjiang River,indicated by high turbidity in the water.Considering the islands off the coast and the complex topography,and the strong influence of tides and wind,the coast off the ECS is a typical region with strong oceanic mixing processes.The changes in the dynamic processes near the bottom play an important role in the control of water turbidity.The turbulent kinetic energy dissipation rate(ε) is a parameter that shows the strength of ocean mixing.This is estimated based on a structure method using current velocity that is measured by a high-frequency Acoustic Doppler Current Profiler(ADCP) from a seafloor observatory in the ECS.The results indicate strong ocean mixing processes with a mean e value of 5.7×10^(-5) W/kg and distinct tidal variations in the dissipation rate.Conversely,the variation of the water turbidity leads to changes in the water dynamical structure near the bottom.Comparing the dissipation rate with the turbidity near the bottom boundary layer,we find that the high turbidity mimics strong ocean mixing.展开更多
文摘目前,地理信息系统(geographic information system,GIS)业界在符号库结构上还没有制定明确的、统一的标准,各GIS商业软件的符号库构建思路和结构各异.充分利用可扩展标记语言(extensible markup language,简称XML)强大的自我描述能力、开放性、平台无关性和灵活性特点,建立一种通用的地图符号描述模型.提出异构GIS平台下地图符号共享的解决方案和实现的关键技术,并在中国岩石圈三维结构数据库项目研究中验证了通用地图符号库实用性.
基金Supported by the National Natural Science Foundation of China(Nos.41106013,41576005)the Shanghai Committee of Science and Technology(No.06DZ12012)
文摘The East China Sea(ECS) has a high suspended-sediment concentration because of the influence of the Changjiang River,indicated by high turbidity in the water.Considering the islands off the coast and the complex topography,and the strong influence of tides and wind,the coast off the ECS is a typical region with strong oceanic mixing processes.The changes in the dynamic processes near the bottom play an important role in the control of water turbidity.The turbulent kinetic energy dissipation rate(ε) is a parameter that shows the strength of ocean mixing.This is estimated based on a structure method using current velocity that is measured by a high-frequency Acoustic Doppler Current Profiler(ADCP) from a seafloor observatory in the ECS.The results indicate strong ocean mixing processes with a mean e value of 5.7×10^(-5) W/kg and distinct tidal variations in the dissipation rate.Conversely,the variation of the water turbidity leads to changes in the water dynamical structure near the bottom.Comparing the dissipation rate with the turbidity near the bottom boundary layer,we find that the high turbidity mimics strong ocean mixing.
