Construction and experiment for sea-level &|land surface system model in the Yangtze Delta Region
长江三角洲地区海面—地面系统模型构建与试验

The S/L (sea-level and land surface) system change plays a very important role in the evolution course of natural and human history in coastal area, so it may be an effective solution to study the environmental evolution and human-land relationship development in the Yangtze delta region by performing a virtual experiment on the platform, which relates to the consolidation of the S/L system integrated study and the construction of a digital and visual S/L system model. From the visual angle of the S/L System, this paper introduces the basic framework about the S/L System model, which is composed of four modules: the sliding bottom boundary calculating, segmentation rate of sedimentation calculating, the ancient land surface elevation calculating and simulated result validating, and throws light on the model's data classification system, as well as the model's basic function aims and on the model realized technology system. Using the DEM and GIS technology, through regulating the variable multi-parameters of sea level changes, sedimentation, crust movements and so on, sorts of maps can be automatically created by the preparatory system model, such as 2D or 3D paleotopographic maps, which are compiled respectively according to the control conditions of the randomly designated time or time intervals. Hence this can be used to dynamically demonstrate the delta plain's paleogeomorphology and sea-land relationship evolution history, besides providing the professionals with a new platform in the delta paleoenvironmental reconstruction and virtual experimental study. Based on the existing data of the Yangtze delta region, a preparatory simulative experiment was done by the model on the sea-land change course in the Yangtze delta region since 10000aBP. The good simulative effect is obvious from the hypsometric paleotopographic map and 3D color shaded-relief map, both the output of the model. This provides a visual scene to analyze and discuss the Yangtze delta evolution, coastline shifting, even the relationship between the ancient civilizations migration and environments.