用数字高程模型进行地表径流模拟中的几个问题

用数字高程模型进行地表径流模拟时，由于网络精度和高程精度的限制，使得在某些局部的模拟结果不理想。针对其中几个关键的技术问题，提出了相应的解决办法。伪负地形填充法可以区别真正的负地形和由于ＤＥＭ误差造成的假象，并对伪负地形行填充。水系图与ＤＥＭ结合的方法可消除径流模拟结果与现有水系不吻合的现象，有效提高径流模拟精度。在地势平坦地区，采取在原ＤＥＭ上加微小修正值的办法，可以得到理想的模拟结果。

Several Problems and Their Solutions in Surface Runoff Modeling

The quality of surface runoff modeling is limited by horizontal and vertical accuracy of digital elevation model. Several critical problems and respective solutions are presented. Method of filling pits based on size can distinguish sink cells due to inland catchment from those due to DEM errors. Method combining DEM with stream network leads to a more accurate drainage network from surface runoff modeling, especially for flat area.Method of modifying existing DEM by adding a small value can produce more realistic drainage pattern rather than parallel flow over flat surface.