Digital ecological model and case study on China water condition

Digital Ecological Model (DEM) is a platform developed with Java. It consis ts of six components: DEMGIS, DEMTSA, DEMSTA, DEMMOD, DEMVIEW, and DEMAPPLE T. DEMGIS features major functions of geographic information system (GIS), such as building digital elevation model, managing gee-referenced database, translating vector data into raster data, and generating geographic graphs with different projections. DEMTSA is used to interpolate the scattered cl imatic data into raster data, by means of trend surface analysis (TSA) meth od and interpolation method. As a plug-in for GIS, DEMSTA provides some wid ely used statistic methods. DEMMOD is a platform for building process-based landscape model. It provides a visual interface - Visual Programming Inter face of Digital Ecological Model (DEMVPI) for ecologists to 'write' and rec ord the models in an interpretation language - Ecological Description Langu age of Digital Ecological Model (DEMEDL). Ecological Model Interpreter of D igital Ecological Model (DEMEMI) is responsible for compiling the programs written in DEMEDL, running the model and displaying the results. DEMVIEW is a tool for viewing and editing some geographic graphs. DEMAPPLET can link a Java applet with gee-referenced database and display the simulation resul ts on the Internet. All the codes of DEM were compiled into Java applicatio n programs, and some of the programs are available on the Internet as Java applets. As a case study, amended Penman's method was used to calculate the potential evapotranspiration and aridity index of China, under present sit uation and three prescribed climate scenarios, which include raising mean t emperature by 1.5, 3.0 and 4.5 degreesC, and raising precipitation by 10%, to assess the potential impacts of global climate change on China water con dition. (C) 2001 Elsevier Science B.V. All rights reserved.