| It is the effective way to realize the highly quantitative study on the geographical process that associates main geographical factors such as climate, hydrology, topographic features, soil, vegetation and human activities with geographical process for quantitatively calculation by selecting suitable spatial scales and using mathematic models based on computer.Distributed simulation study of multi-geographical process was carried out in the study area of Lianshui Basin, Xingguo County, Jiangxi province supported by RS and GIS, using the simulation models system developed by USDA. This project is funded by the national natural science fund titled "Integration and Systematization of Mathematic Models for Soil and Water Resources Study in a Basin and Its Application ". The main contents and research results are as follows:(1) The characteristics and the development of Basin models and Basin simulation technology were systematically studied in this dissertation. The application of Basin simulation integrated with RS and GIS technology was fully explained from theory to practice. It was proved by the practice that the integration of basin models, RS and GIS is indispensable for basin simulation technology shifting from the lumped to the distributed system.(2) The method of distributed hydrological modeling based on raster Digital Elevation Models (DEM) was applied to generate basin network, to divide sub-basin and generate basin boundary automatically. Through discretization at most 102 sub-basins and 649 Hydrological response units were produced in the study area and spatial discretization of the basin were successfully realized. A series of technological problems such as the accurate generation of basin network in plate area and error correction of basin boundary were solved in the research process.(3) Parameters for model running including topography, soil, climate and land use were extracted by means of RS, GIS and statistics methods using present data of study area, spatial parameterization process of the basin was successfully realized and soil parameters calculation, temperature, precipitation spatial correction and land use supervised classification were studied in this dissertation.(4) Using GIS database function, the model parameters extracted from the process parameterization were managed in the database. According to the model requirement, the database fields were set up corresponding to the contents of parameters and tables relevant to spatial features were also constructed and the auto-evaluation of discretization unit were solved. According to the grading spatial relationship, discretization unites were routed upwards and the spatial integration of the simulation results were gradually realized.(5) computer simulation of multi-geographical process in Lianshui basin was carried out using data of 10 years and 4 spatial scales and quantitative simulation results were obtained. The simulation accuracy of annual water yield for 4 spatial scales was above 89% and the best simulation accuracy of annual sediment yield was also above 75%. The spatial distribution of the sediment yield in the study area was analyzed using the simulation results.(6) The simulation results under the four spatial discretization scales were analyzed by compare study and the affect factors were also studied. It was found that the changes of the spatial scales have the smallest affect on water yield simulation but enjoy comparative higher affect on sediment yield. With the increase of the spatial discretization units, the simulation accuracy of sediment yield was also improved. It came to a conclusion that the sediment yield in Lianshui basin was with source limitation characteristic and channel transportation process had significant influence on the sediment yield in this dissertation.
|
PDF Full Text Request