陕北黄土高原正负地形研究(英文)

The Loess positive and negative terrains (P-N terrains),which are widely distrib-uted on the Loess Plateau,are discussed for the first time by introducing its characteristic,demarcation as well as extraction method from high-resolution Digital Elevation Models. Us-ing 5 m-resolution DEMs as original test data,P-N terrains of 48 geomorphological units in different parts of Shaanxi Loess Plateau are extracted accurately. Then six indicators for de-picting the geomorphologic landscape and spatial configuration characteristic of P-N terrains are proposed. The spatial distribution rules of these indicators and the relationship between the P-N terrains and Loess relief are discussed for further understanding of Loess landforms. Finally,with the integration of P-N terrains and traditional terrain indices,a series of un-supervised classification methods are applied to make a proper landform classification in northern Shaanxi. Results show that P-N terrains are an effect clue to reveal energy and substance distribution rules on the Loess Plateau. A continuous change of P-N terrains from south to north in Shaanxi Loess Plateau shows an obvious spatial difference of Loess land-forms and the positive terrain area only accounted for 60.5% in this region. The P-N terrains participant landform classification method increases validity of the result,especially in the Loess tableland,Loess tableland-ridge and the Loess low-hill area. This research is significant on the study of Loess landforms with the Digital Terrains Analysis methods.