新疆地貌空间分布格局分析

以高分辨率遥感影像为本底数据的最新新疆地貌数据,能提高定量化地貌格局分析结果的准确性、客观性和科学性。本文利用地学统计和GIS空间分析方法,基于最新新疆地貌数据,定量化分析了地貌的分布特征、空间格局。结果表明:(1)大地貌单元中,平原地貌约占新疆总面积的1/3;(2)地势分级,中海拔地貌占绝对优势,约占全疆总面积1/2;(3)形态类型中,丘陵地貌在地势起伏中占主导地位,面积最大,主要分布在两大沙漠中,以沙丘形式分布;(4)基本地貌类型,中海拔丘陵最多,占总面积的21.417%;(5)成因类型中,流水、风成和干燥作用占主导地位;(6)受不同形成条件和控制范围的影响,新疆成因类型的分布特征随着海拔和起伏的变化而变化;(7)总体上,新疆地貌的空间格局呈现出两大特征:水平环形特征和垂直地带性特征。

The spatial distribution patterns of digital geomorphology in Xinjiang

Based on the data of digital geomorphology with a scale of 1:1 000 000, this study analyzes spatial distribution of geomorphologic patterns in Xinjiang. The geomorphologic types were artificially visually interpreted from the multi-sources data including the TM/ETM imageries (a resolution of 30 m) around 1990 and 2000, the Shuttle Radar Topography Mission (SRTM) digital elevation model (USGS, 2004) with a horizontal resolution of 90 m, geomorphological maps and geological data etc. The quantitative indexes of the classification system of the digital geomorphology include altitude, relief, genesis, sub-genesis, morphology, micro-morphology, slope-aspect, and lithology, etc. The methodology of geo-statistics and GIS spatial analysis were used in this article. Firstly, the overall features of geomorphology were presented from three levels, i.e., altitude, relief, and basic morphologic types. Secondly, the spatial distribution patterns of different geomorphologic types were analyzed from the features such as altitude, relief, genesis, sub-genesis, morphology and micro-morphology. The results show that: (1) compared to the mountain types, the plain accounts for about 1/3 of the total area in Xinjiang; (2) in terms of absolute altitude, the area of the geomorphologic types of middle altitude (1000~3500 m) makes up about 50%; (3) the hill types (< 200 m) dominates the morphologic types, mainly distributed in the Tarim and Junggar basins, which presents the feature of sand dunes; (4) in the basic morphologic types, the area of the middle-altitude hill types possesses the largest area, being about 21.417%; (5) fluvial, arid and aeolian landforms are the dominant types among all of the genesis types; (6) in general, there are two main characteristics in the spatial pattern of geomorphology in Xinjiang: the horizontal ringed and vertical zonal distributions, from basin center to the highest-relief highest mountain, the genesis geomorphologic types changes from lacustrine landform, aeolian landform, arid landform, fluvial landform, peri-glacial landform, to glacial landform etc. This study provides a scientific basis for a better understanding of the spatial distribution pattern of geomorphology in Xinjiang. It also provides the basic data for the future analysis of the potential arable land resources, prone-to-desertification regions, the distribution of glaciers, and other information, as well as regionalization, sustainable use and development, the restoration of ecological function, etc.