【摘要】 预先利用CTSU海啸数值模型模拟出可能存在的各种假想海啸源。运用海啸数值计算模型,分别就5个不同震级(6.5、7.0、7.5、8.0、8.5)、6个不同震源深度(0、20、40、60、80、100 km)的1 400多个假想海啸源进行海啸数值模拟,模拟的时间步长为1 min,空间网格以2′为间隔,模拟区域为104°~132°N、0°~32°E。按照引发海啸的级别不同,将数模计算结果存贮于数据库之中,并在应用时基于GIS网格建立快速内插索引,自动输出预警信息,并在GIS界面中提供可视化表达。系统采用模板文件来定义预警分析的范围和内容。在海啸预警分析时,系统主要使用以下4个模板:(1)海啸源网格模板,该模板定义了整个预警场中可能存在的海啸源地理位置和相关属性;(2)海啸预警网格框架模板,此模板定义了整个海啸预警分析场中最后需要汇总的岸线网格位置;(3)海啸预警岸段网格模板,该模板用来定义预警网格归于哪一个岸段;(4)海啸预警城市网格模板,这个模板可以定义用户最为关心的重点城市的海啸预警信息。系统采用GIS界面,预警分析操作十分简单,系统运算也非常快,输入地震的精确位置、地震强度以及震源深度3个参数后,系统将自动执行一系列运算,在1~2 min内便可计算出所有海啸预警信息,并自动将预警信息在GIS界面中显示出来。最终以web网页的形式向公众发布海啸预警信息,达到了快速海啸预警分析的目的。网页开发采用Ajax技术,同时借助Google Maps API函数实现了预警信息的显示与维护。网络客户端仅需要1个浏览器,就可以实现有关信息的查询。系统在海量数据存贮、快速查询和分析等方面较好地解决了相关的技术难点,它对提高海啸防灾减灾科学决策能力具有重要意义。更多还原

【Abstract】 Tsunami refers to the wave produced by dramatic fluctuations in the ocean,which is mainly caused by undersea earthquakes.When the tsunami wave spread to shallow coastal areas,its tremendous energy often leads to severe loss of life and property.The Pacific rim is the tsunami-prone areas in the world,and the eastern area of China is just located in this area of the Northwest Pacific coast,which greatly risks the tsunami disaster.Building tsunami warning information system is an integral part of the tsunami disaster mitigation effort in the Chinese coastal zone.This paper provides the framework design of tsunami warning information system based on GIS,and the integration of numerical simulation model and database.First,China Tsunami Simulation Utility(CTSU) is introduced.It is a numerical model developed by the Static Ocean Environment Forecast Center of China.Various tsunami sources that may exist in the ocean are supposed,based on which tsunami warming information is simulated with the CTSU tsunami numerical model.The numerical simulation uses more than 1 400 hypothetical tsunami sources,and each tsunami source has 30 cases of five different seismic magnitudes(6.5,7.0,7.5,8.0,8.5) and six different focus depth(0,20,40,60,80,100 km).The simulation’s time step is 1 min,the model spatial grid is divided by the interval of 2′,and the simulation region ranges from 104°~132° E and 0°~32°N.Second,the primary warning information database is constructed in Oracle,and all the simulation results produced by CTSU are put into the database table in accordance with the querying information,which includes different magnitudes of tsunamis and the global index for rapid interpolation in the application of this system.The warning information is output automatically and expressed visually in the GIS interface.The system uses four template files to define the scope and content of warning analysis.(1) Tsunami Source Grid Template,which defines the geographic location and associated attributes of tsunami sources that may exist in the whole warning field.(2) Tsunami Warning Grid Frame Template,which defines grid position of shoreline,which is needed to aggregate tsunami warning information at last in the whole warning analysis field.(3) Tsunami Warning Coast Segment Grid Template,which is used to define which coast segment the warning grid must be attributed to.(4) Tsunami Warning City Grid Template,which is used to defines the warning information of key cities that users are most concerned with.The system runs very fast and its operation is simple.By entering the exact tsunami source information,which includes location of the earthquake,seismic intensity and focus depth,it will automatically perform a series of calculations and display all the tsunami warning information in the GIS interface within 1~2 min.Third,the web publication of the tsunami warning information is quickly released to the general public in the form of web pages.The web development uses Ajax technology and greatly supported by the Google Maps API function for warning information display and maintenance.Only one browser is needed for the customer to consult relevant tsunami warning information.This paper provides some resolutions for related technical difficulties,such as the mass data storage,fast query and rapid analysis,and the operation of this system has great significance in improving scientific decision-making capacity of tsunami disaster mitigation.更多还原