地形分析与地理信息系统在水文地貌学中的应用

TOPOGRAPHIC ANALYSIS WITH GEOGRAPHIC INFORMATION SYSTEMS IN HYDROGEOMORPHOLOGY

本文阐述了利用地理信息系统进行大面积及高分辨率的地形分析方面的最新进展，并且讨论了一些由地理信息系统获得地形参数的规律，并提供了作者本人的一些设想．

Topographic factors are important in controlling the earth's surface processes and thus human economic activities. Due to a rapid development of Geographic Information Systems (GIS) and existence of Digital Elevation Models (DEM),topographic analysis with a high spatial resolution for a watershed or a drainage basin becomes possible. Topographic factors have to be taken into account in many numerical models simulating the earth's surface processes. GIS is the best tool to handle DEMs and to produce various topographic parameters for the numerical simulations. Moreover, GIS itself can model the earth's surface processes and the modeling results often have a high statistical signilicance and a high spatial resolution.In hydroclimatic and hydrogeomorphic studies of mountain areas, topographic analysis with GIS can be a necessity. For example, to understand a long-term climatic relationship between the Pacific Ocean and the western North America (WNA), we must understand the air-mass configurations of the historic time (past 150-200 years) and probably tree-ring record hme (past 400-600 years). However, the copmplex topography in WNA has complicated instrumental and tree-ring records. Topographic analysis of DEM data wigh GIS can filter all topographic factors and allows an accurate reconstruction of airmass comfigurations for the past 400-600 years. Another example deals with a quantitative paleoclimatic reconstruction of Great Salt Lake for the Last Glacial Maximum. Dur ing that time, the lake level rose and lake area expanded dramatically, but glacial advances in the Wasatch Mountain were relatively limited. With a full comsideration of topographic influences on the mass-balance and energy-balance for both glacier and lake, through DEM data processing withim GIS modulation, we can model: under What conditions, a rapid areal expansion of the lake did not inhibit a continuous rise of lake level while the glaciers did not advance comsiderably.