The variability of the snow and ice melt in alpine rivers in northwestern China

The study of snow and ice melt （SIM） is important in water-scarce arid regions for the assessment of water supply and quality. These studies involve unique difficulties, especially in the calibration of hydro-models because there is no direct way to continuously measure the SIM at hydrostations. The recursive digital filter （RDF） and the isotopic hydro-geochemical method （IHM） were coupled to separate the SIM from eight observed series of alpine streamflows in northwestern China. Validation of the calibrated methods suggested a good capture of the SIM characteristics with fair accuracy in both space and time. Applications of the coupled methods in the upper reaches of the Hei River Basin （HRB） suggested a double peak curve of the SIM fraction to streamflow for the multi-component recharged （MCR） rivers, while a single peak curve was suggested for the rainfall-dominant recharged （RDR） rivers. Given inter-annual statistics of the separation, both types of the alpine rivers have experienced an obvious decrease of SIM since 196os. In the past 10 years, the SIM in the two types of rivers has risen to the levels of the 1970s, but has remained lower than the level of the 1960s. The study provided a considerable evidence to quantify the alpine SIMbased on the separation of observed data series at gauge stations. Application of the coupled method could be helpful in the calibration and validation of SIM-related hydro-models in alpine regions.     

RDF/XML在地学数据Web共享中的应用研究

本文基于W3C推荐的资源描述框架（RDF）,利用RDF/XML语法法规范实现了地学多学科元数据的表达和交换;设计了地学多学科元数据扩展和共存方案;以RDF／XML为中间层,构建了地学数据Web共享的基本框架。研究表明RDF／XML在地学数据Web共享中的应用前景十分广阔。     

RDF/XML在口岸GIS中的应用

口岸GIS是口岸管理数字化和现代化的基础设施之一,而数据岛的建设又是基础中的基础。RDF/XML是一个用于网络环境可伸缩的海量数据包装容器,其特点是:RDF可定制各类属性元素;便于各类数据的关联;具有良好的互操作性,便于数据交换和共享。RDF/XML的应用为口岸GIS的智能化开辟了广阔的前景。     

地形数据库增量信息数据建模及其RDF描述

为了保持用户数据库现势性,需将数据库更新过程中产生的增量信息及时发布给用户。而增量信息的建模与描述是实现发布的前提。以中国1∶25万地形数据库的两个版本为例研究了增量信息的数据建模和数据描述的问题。提出了基于超图数据模型的建模和基于资源描述框架（RDF）的增量信息描述方法。该方法能够以统一的方式实现不同增量信息的建模和描述,具可行性和有效性。     

WebGIS数据组织发展研究

本文论述互联网GIS数据组织的发展状况。首先介绍了在WebGIS环境下空间数据的特点及其管理上存在的困难，并分析了目前实现WebGIS数据组织的几种技术及其优缺点，最后说明ontologies和RDF在WebGIS数据组织中的具体应用。