水文观测数据是进行流域水文科学及相关科学研究的基础。在回顾国内外水文信息系统及水文数据共享现状的基础上,通过系统收集和整理黑河流域水文观测数据,利用协同促进水文科学发展大学联盟水文信息系统(Consortium of Universities for the Advancement of Hydrologic Sci-ence,Inc.-Hydrologic Information System,CUAHSI-HIS)提供的水文服务器(HydroServer)组件进行了黑河流域水文数据共享发布平台的设计与实现。系统主要采用了观测数据库模型、Web-GIS地图缓存技术和Web Service技术,建立了一个具有水文观测数据检索与浏览、在线服务与分析功能的水文信息共享发布系统。
Manas River,the largest inland river to the north of the Tianshan Mountains,provides important water resources for human production and living.The seasonal snow cover and snowmelt play essential roles in the regulation of spring runoff in the Manas River Basin(MRB).Snow cover is one of the most significant input parameters for obtaining accurate simulations and predictions of spring runoff.Therefore,it is especially important to extract snow-covered area correctly in the MRB.In this study,we qualitatively and quantitatively analyzed the uncertainties of snow cover extraction caused by the terrain factors and land cover types using TM and DEM data,along with the Per(the ratio of the difference between snow-covered area extracted by the Normalized Difference Snow Index(NDSI) method and visual interpretation method to the actual snow-covered area) and roughness.The results indicated that the difference of snow-covered area extracted by the two methods was primarily reflected in the snow boundary and shadowy areas.The value of Per varied significantly in different elevation zones.That is,the value generally presented a normal distribution with the increase of elevation.The peak value of Per occurred in the elevation zone of 3,700–4,200 m.Aspects caused the uncertainties of snow cover extraction with the order of sunny slope>semi-shady and semi-sunny slope>shady slope,due to the differences in solar radiation received by each aspect.Regarding the influences of various land cover types on snow cover extraction in the study area,bare rock was more influential on snow cover extraction than grassland.Moreover,shrub had the weakest impact on snow cover extraction.
